study of folded plate structure

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Lehigh University Lehigh Preserve eses and Dissertations 1963 Study of folded plate structure Pierre Chevin Lehigh University Follow this and additional works at: hps://preserve.lehigh.edu/etd Part of the Civil Engineering Commons is esis is brought to you for free and open access by Lehigh Preserve. It has been accepted for inclusion in eses and Dissertations by an authorized administrator of Lehigh Preserve. For more information, please contact [email protected]. Recommended Citation Chevin, Pierre, "Study of folded plate structure" (1963). eses and Dissertations. 3147. hps://preserve.lehigh.edu/etd/3147

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Page 1: Study of folded plate structure

Lehigh UniversityLehigh Preserve

Theses and Dissertations

1963

Study of folded plate structurePierre ChevinLehigh University

Follow this and additional works at: https://preserve.lehigh.edu/etd

Part of the Civil Engineering Commons

This Thesis is brought to you for free and open access by Lehigh Preserve. It has been accepted for inclusion in Theses and Dissertations by anauthorized administrator of Lehigh Preserve. For more information, please contact [email protected].

Recommended CitationChevin, Pierre, "Study of folded plate structure" (1963). Theses and Dissertations. 3147.https://preserve.lehigh.edu/etd/3147

Page 2: Study of folded plate structure

r,· . . .

•·~ I'

StDDY OF A FOLDED PU.TE SD.UCTUIE

by

Pierre Chevin ! -

• . ,,iJ ...

A Thesis

Presented to the Grad~te Faculty

of Lehigh University

in Candidacy for the Degree of

Master of Science

Lehigh University

1963

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This thesis is accepted and approved in partial

·fulfillment of the requirements for the degree.of Master of

Science in Civil Engineering.

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(date)

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:.,

w. J . Depa ment

Professor in Charge

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Page 4: Study of folded plate structure

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"', mz:aaa t t &J!AJL, : : aiiiiiiii.._;;;;.;; .. ;; · · ·. .• : =· · · · · 1 .·.·. .. ·.. . . • . . .· .. :. 4 . ... , . 1 • • .....•. , . . . . .... .krJW.Q_-..C.BD(di6;i6 Mi _,,..... -....-_..._,.. ____ ,_ ,, _____ ......... _....,,._,_,_.,__..,...,~-~ .... ~-----· ti!!. !~; •• ,na1.,

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A C K ~, .Q. fl L E, D. G M E N T §

This thesis is an attempt to verify experimentally the theory

relative to the Folded Plate Structures. All the tests were performed

at Lehigh University in the Models Laboratory of Fritz Engineering

Laboratory from September 1961 to May 1962.

The author is indebted to Professor Eney, Bead of the

Department of Civil Engineering, and Fritz Engineering Laboratory, who

was Thesis Supervisor and to Professor Le-Wu Lu, whose guidance was

greatly appreciated.

' Thanks go to I. J. Taylor, Instruments Associate who helped ,

with instrumentation and strain gage application necessary for the test.

Sincere appreciation must b~ .. exten4ed to Mr. E. Zanoni, who ,f -- . . .,,h . ,).

worked on the same model in 1960 and 1961 and whose experience was very

helpful.

Mrs. D. Fielding typed the manuscript and her sympathy and '\,

comprehension are gratefully acknowledged . .

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TABLE OF CONTENTS·

ABSTRACT

.1. INTRODUCTION

A. GENERAL ASSUMPTIONS

B. DEFINITIONS

2. DESCRIPTION OF THE STRUCTURE

,.

3. ANALYSIS OF STRUCTURE

... ,_ \ ...

Page, (

1

2

:4:

s:

A. OUTLINE OF METHOD ·7

B. COMBINATION OF ELEMENTARY LOADINGS 9·

C. COMPLETE ANALYSIS FOR THE ELEMENTARY LOADINGS 16

D. ·RIDGE STRESSES WHEN THE MODEL IS SUPPORTED BY 33

INTERMEDIATE COLUMNS AT MIDPOINT

E~ RIDGE STRESSES DUE TO THE TIES

·4. DESCRIPTION OF THE HlDEL

40

47

-A. MATERIAI,

B. THE M:>DEL I TS ELF

C. SUPPORTS

., r

. . ;- .

5. . TESTS ON THE K>DEL

·,: . ·::.•

A. PRELIMCNARY TESTS

B. ACTUAL TESTS OF THE LOADED K>DEL . ~-

C. THE ADOPTED SOLUT"ION

D. STRAINS AT RIDGES, FROM THE STRAINS AT

SR-4 LOCATIONS

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Page 6: Study of folded plate structure

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T A B L E O F C O N T E N T S {continued

6. DISCUSSION OF THE RESULTS AND CONCLUSIONS

A. DISCUSSION

B. CONCLUSIONS

7. SUGGESTIONS FOR FURTHER TESTING

A. EFFECT OF DIAPHRAGMS

B. PROPOSED TEST '

Page

62

62

64

66

66

66

C. STRESSES DUE TO A DIFFERENTIAL SETTLEMENT 67 '

OF THE SUPPORTS

D. MEASURE OF DEFLECTIONS

8. APPENDIX

RIDGE STRESSES FOR THE ELEMENTARY LOADINGS

ACTUAL RIDGE STRAINS (TESTS DATA)

6:7

6-S.

69 ·- 7'6

77 - 88

FINAL STRESSES (THEORETICAL AND EXPERIMENTAL) 89: - 100

REFERENCES lQl . '

VITA i 102.:

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Page 7: Study of folded plate structure

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LIST OF_TABL'ES

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Table j

1 ACTUAL LOADING VERSUS ELEMENTARY LOADINGS

2 PLATE LOADS

3 MOMENTS DUE ro PLATE LOADS

4 NON-CORRECTED STRESSES FOR l'lm ELEMENTARY

LOADINGS

5 DEVLECTION OF PLATES

MOMENTS AT RIDGE 4

:j .,~~

RIDGE" LOADS EQUIVAJ,ENT 'lU THE POINTS

{".. DISPLACEMENT

8 STRESS CORRECTION COEFFICIENTS

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LIST OF FIGUR-ES

THE STRUCTURE

THE KJDEL ) .

, ....

POINTS SUPPORTS

COLUMN SUPPORT ~

'IYPICAL TIE

THE ''LOADING TREE"

ATTACHMENT OF THE LOADING TREE

STRAIN READING EQUIPMgNT '(.

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Page

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50

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ABSTRACT

David Yitzhaki developed a simplified theory for the

analysis of the Folded Plate .Structures.

~theory.

\

The purpose of this thesis is to verify the validity of his

A simple structure was chosen and analyzed for several cases ~, \~.

of loading under different conditions of supports. In this manner

the stresses at the joints of the structure were determined.

A model was then built in plexiglas and the strains were

measured at the joints. After determination of the Modulus of

Elasticity of the material the stresses were computed.

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Finally the theoretical and experimental results were compared.

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Page 10: Study of folded plate structure

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I 1-. ~ N T_R O D 1! C T I O N

.... (

The use of the folded plate structures has considerably in-

creased in the past decade mainly for the simplicity of their con-..,

struction. This type of structure is particularly well adapted to the

large buildiJi,gs, where a vast free space is needed since no columns are

1'f necessary tor supporting the roof. ..

·-The main obstacle to a wider use has been the complex-ity of

the theoretical analysis of the prismatic structures. In 1958 Yitzhaki

prepared a simplified method which can be used by any designing engineer.

(Ref. No. 1). This approach will be followed here for determining '), ... ) . .,

theoretically the stresses induced in the ridges of a folded plate roof. '

The object of this study is to verify experimentally the

assumptions connnonly used in the analysis of folded plate structures.

These general assumptions have been defined in detail by Boward

Simpson (Ref. No. 2). They are as follows: / .

A. GENERAL ASSUMPTIONS

"1. The material is homogeneou~ ,_ uncracked, ~n(.f •

elastic. ~

2. Longitudinal edge joints are fully· monolithic

and continuous; there is no rel.ative rotation

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Page 11: Study of folded plate structure

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or translation of two adjoining plates at their

common boundary.

.3. The principles of sup'erposition hold; that is,

the structure may be analyzed separately for

the effects of its redundants and various

external loadings and the results added.

4. Individual plates possess negligible torsional

resistance. Torsional stresses du·e to twisting

of the plates can be ignored.

-5. The function of the supporting diaphragms or

bents is to supply the end reactions for the

plate action and for the longitudinal slab

action. They are assumed incapable of providing

restraint against rotation of the ends of the

plates in their O'Wll. planes, but may provide some

end res tr'ain t for longitudinal slab bending.

..

The following additional assumptions can be made if

each plate is relatively long compared with its width -

( length-to-width ratio of, say, three or more):

6. Longitudinal strain due to plate action varies

linearly across the width of e~ch plate ('~lane

sections remain plane"). '!he rate of change of

strain with respect to width ordinarily will

differ from plate to plate, however, from which

- it can be inferred that there will be some

'\··.

· relative displacement of the joints of a cross-section.

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Page 12: Study of folded plate structure

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7. Longitudinal slab action can be neglected; that

is slab bending carries loads applied to the

surface of a plate to the longitudinal edges

only, as in a one-way slab system."

)

These assumptions will be more clearly understood, if a few ,

terms are more fully ~plained.

B. DEFINITIONS

··;-

"The individual planar elements com.prising the

structure will be termed ''plates."

The "length" of a plate is its dimension between

the diaphragms or ribs; its ''width" is the perpendicular

-· distance .between its two longitudinal edges.

In conformance with the terminology introduced by

Winter and Pei,(3) '~lab'' action will be used to refer

~-

to bending ··of the individual plates out of· their planes,

and ''plate" action to bending in their planes. (The

latter has been termed "disk effect" by Craemer ( 4) ,

and 1\nembrane" action by Ashdown. (S)"

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Page 13: Study of folded plate structure

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,,,-:ii . . . ,, . ---·----- ........................ ·---·- ----··--·-- --- . . - - -,· .. ··- ·.·- --- -·----·-- ·.-- ..... · ... __ .. ~\-'w:--····----.. _ .. ·-- :_ -,--- '" ..... - .. -- - - .. .._ .. : . -

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i . 2. D E S C R I P T I Q N O F T H E S TR UC T UR E

I

of a fic'tftious structure has been built because a ,,~

'1-e model

struct~~ ~£ these L.-,'

proportions is not used in an actual building. Gener-

ally the buildings are flatter. The dimensions of the model were deter­

mined in such a way that the theoretical analysis is as simple as possible.

The structure (Fig. 1) is composed of five identical plates;

(length L, width d, and thickness tare the same for the five elements). '

The angle between two adjacent plates is constant around the structure.

L = 36 in.

·d: • 5 in.

t ~ 0 .125 in.

A·= d x t = 0.625 in. 2

t d2 l s •

12 = 0.521 in.3

t d3 I= 12 = 1.302 in. 4

.. (

The model is closed at its ex1tremi ties by a diaphragm, the

thickness of which is t (theoretically the thickness of the diaphragms

is without importance since the diaphragms are assumed (Assumption No. 5)

to behave as simple supports:

..

The six ridges are referred as O, 2, 4, 6,·a, 10

The five plates are referred as 1, 3, 5, 7, 9

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Page 14: Study of folded plate structure

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Fig. 1 : THE STRUCTURE

= 36 in. = 5 in. = 0.125 in.

2 - d X t - o.625 in - - • 3 d2/12 0.521 = t· X - in. -= t X d3/12 - 1.302 in4. -

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Page 15: Study of folded plate structure

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:3 • A N A L Y S . l S O F S T R U C T U R E

A. OUTLINE OF METHOD

'nte purpose of this analysis· is to determine the stresses at·tbe ·

Joints of the structures (including the free edges).

\

4 6

2 s ,.

0 10 ·O··

For any type of loading:

1. Consider first the joints 2, 4, 6, and 8 as being fixed

and determine the reactions of each support, the t:'"i

"'

structures being continuous:

0 10 = free = end of ·c.ant·ileve:rs·

· 2, 4, 6, 8 = fixed

The only loading to be analyzed are vertical ones.

Under these conditions 2 and 8 serve as hinges.

0 10 free

2 8 hinges

4 6 ,j .

fixed

I

2. Resolve thes·e reactions into forces· acting in the ~planes of··, ,

of the plates.

J. Consider each plate as a beam carrying the plate forces.

Determine moments. · For each plate write the equations .. ··-··~

., ·- ....

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,.

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Page 16: Study of folded plate structure

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of equilibrium. By consideration of compatibil.~ty ',.

define the stresses existing at the edges.. These

are the initial stresses (or stresses without

corrections).

4. Allow the joints to deflect. Determine the

displacements at the joints corresponding to

5.

the state of stresses e.atablished before. The

procedure is as follows: Define -

a. The deflection of each plate in its plane

b. The deflection of each joint (by using

the Williot-Mohr diagram)

c. The relative displacement of two con-

secutive joints .'lo

Determine the moments induced by these

displacements at each joint. These moments

will induce· lateral bending in each plate.

According to the assumptions made, there should

be no lateral bending, only a longitudinal one.

The correction will be obtained by "suppressing"

this bending,._

:"6. Determine the forces acting at the ridges which

will prevent these bendings from :occ·urring. This

is the secondary loading (also called normal

loading) •

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Page 17: Study of folded plate structure

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7.

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From there on, repeat the procedure used before,

starting at step 1 in order to det·ermine the

stresses acting at the ridges, due to the secondary

loading which are the correction stresses.

The final stresses are simply the respective

s1mnnations of initial and correction stresses.

B. COMBINATION OF El.gENTARY LOADINGS

The model will be tested for various types .. of loading. For each

of these cases a theoretical solution has to be provided in order to

check the validity of the theory. Instead of developing a complete

solution as outlined on page 7 for each type of condition, it is much

simpler to derive the solutions for a limited number of elementary i \

.... loadings, which will be combined with the appropriate coefficients 1.n ,

order to match the real loading situation.

The method of Yi tzhaki (Ref. 1), based on the combination of

symmetrical and antisymmetrical loadings, is used here. -...

1. Elementary loadings for cases of external vertical

loads, uniformly distributed along the length of

the structure.

As the load is to be converted into ridge-loads, only

ridge loading cases need be analyzed:

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Page 18: Study of folded plate structure

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b.

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Sy, ... netric.a.1 r.i.dge- '11.ne loads , 100 100

100 1 I ~-~

U S 0 U S I

USO= Uniform Symmetrical Outside 'Line Load

US I= Uniform Symmetrical lnaide Line Load ··--

ridge line loads ~

100 -.100 100 100 i t

UAO U A I

U AO= Uniform Antisynunetrical Outside Line Load

U A I= Uniform Antisynunetrical Inside Line Load

Any case of vertical, uniformly distributed load may be obtained

by the combination of these four elementary loadings.

2. Elementary Loadings for center line reactions

The model will be tested for different conditions of

supports.

a. Simply supported

b. reposing on two middle columns

c. With ties placed at the top of the vertical

walls

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Page 19: Study of folded plate structure

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···, :/··--~ ..

f

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1000

' . ·"•'

2.1 Reactions due to central columns·

I C S

1000 1000

f CA

1000 1000

C S = Col.ti.inns , symmetrical

c·. A = Columns, Antisynnnetrical :·:2i .• 2: E:ff~ct, ·au;e to the tie

1000 T S

TS = Tie, symmetrical

Q

.,

1 . 1000

t 1000

'

No antisynnnetrical case is needed since the force carried by the

·ti~ is constant from one end to the other.

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~~' · .:-.;---.; ..... ~u1.~:......_ __ ,_,"'....._~.g_·~ . ..,-~~ ... ~;,. .. ;~w::-:uuir~,:·1:;;;g~ ,...,....,~-·.- .::.:.i....~"ff..R:,.:",~--.___... • ._ .... ~--~~ • ..i.......:....,.r•':;,t.,...1, 'o.;:J~i.:"·~-~~~.=:"'"•;,...,,..ro_. .............. ~:~~~ !",;,,; .. ....=~ .... _ ..... :-,:·,1:-. .. ,.·-.. --.._.........., _ •',,. '•"•._. ..._ .,-,,, i.• · .- , .. ,oo • .-.. ~----I -~--.. --,._ __ ,_ ,,

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Page 20: Study of folded plate structure

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. • • .. • '-{" .. """~',I, ' "

p • ,. , i •• L" t·,,

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3. Combination co.efficients:· for the loads actually

applied to the s true ture.

100 100 100·

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:(:l:). (3)

( l) = Cen·terft·ne loa.dl,1'g_· !:.'I.

(2.)\ Rid'ge 4 line loading

(-3...) C.e..nter line:_-Plate 3 line·· loading

Analysis of _c-as_e (1): . ·• .-

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Page 21: Study of folded plate structure

. /

i.

.. - +--i

... ,. ,,,, ....

:•. r , ..

p 3 5

M = S · B P = 0. 3 75 P

t 1 I' }~ 0. SP O. 5P 0.106065P 0.106065P 0.106065P 0.106065P

p

l 1 t -~

0.106065P O.f06065P 0.!06065P 0.106065f

l

In terms of the elementary· loadiTI:gs ..

(1) = (-0.106065 (USO) + 0.60606S(t1Sl)}r~o . ·- ...

..

:·~'a.J.::y$:.:Ls: .o:f case (2} :.: . .-. •·.. . . •' - . ·-:: ... '

p

l O.SP O.SP ~ t

-- +

(Z) .·;;: (0. 5 (lJS:t) + 0, 5 {UAI)) iriO . . . . . -- ·- .. . ··, :. ·: .. ··

• ,•' :MO •

.Analys:i.s of case (3):

O.SP 0.5P 0.5P 0. 5P

-- +

•• {.i·

-13 ·-··",

Page 22: Study of folded plate structure

.. -14 l. •• ,, _ ... ..t. ... ,- .............. . .. . . . ,,, .. -.

' '' , .. ,... , .... , • '•''1>""~ ..• . . ......... "':'" •. ,.' ·~·. .. ,,,., . ,,,.,,,.. .... . ....... :

., ...... ' .- .. [ . . . . • ··.· -.·-:··-·. >-·~ -.. --:. -.. ·--·.--~- .. ·. .. . . . ·-··· ·--· w.---· - -------.-- __________ ,,l_ ---·-·-···--'·-::·----.. ---·--=- - ....... __ ··-·--- . -- ... ---· ~ .- . . . ....._ ... - -- ~-~ -.--

Syrmnetrical factors: .. -;

-0. SP O.SP M = 0 .125 P

I l ~l. )~ t t t t ., ..

0.25P 0.025P

' t t 0.225P 0.275P 0.225P

O.SP 0.SP

~ t . . M:;:: O.r7314P

< t t t 0 .25P 0.0417P 0.10059P 0.10059P 0.0417~:

t t

0.2083P 0~06P 0.3506P- 0.2083P "'

(3) = (0.225 (US()) + 0.2}.5 {t1ST) +. Q.2083 (UAO) + 0.3506 (UAI)) l~O ·. '

. ' . . .

\

.. . ...

·,... ·:. ·\ . ·•

< .. ~

: "·-,-.,. .

, -·- _.._ , • ' · • •. • -- -.jt.' • .:.--- ' - - : , ' ·.: • · •• _ '_.,.,:....,.:. ..... ·;_!.!;_~.,.....,.,. _ _._~.., . .,.- ..... ·~~- -..::-""...;.____-.. =·-- ·- , :. ............... _,"C.'C't-;-· .._ .... _____ .._ ___ ...... · ... • ··.-.- 1 ~".' • .,, -=~-· ---...=,··_,. ___ -~----,, .. ~-.,;a;.~=-11..:··~ ... .:.::.-- ... ...,,_~~J;:-..:l..~~-:1--·--':,.~·~1.-=::-...:;;.=u..~.~-.;,..;;~;;.;..-,.;.;;.,·.•-~-·:~.· .. ·• -~~:_ ____ ._.. _ _. _ ___...__.;. •. ,...,._..,.__.1. .... ......::....---.-::...;...;....:~1~~_.____:..s...::~~_.;...-~,..;..!"-:"'""~;,..J~..-W:.--·•~ .. _ ~ ---------------------v- - - -~~ ___ ....__ ----.- ------ ----- ~---r ,. --- ...- - -- ,,.~- .,-------- ........,,. - • ' · .... ,t 'O . . . . ""'·'

Page 23: Study of folded plate structure

Ii I l

i I ! ~ t @ fi ~ t •! Ci E I

I I I I J ill

I I

.q,

<.9

, , ..

• .

TABLE 1 · ACTUAL LOADING VERSUS. ELEMENTARY LOADINGS

u s 0 u s I u A 0 UA I

'

·fl) ; ' .. '·: - 0 .106065 + 0. 606065 0 0

(2) 0 + 0.5 0 + 0.5 '.

(3) + 0.225 + 0.275 + 0.2083 + 0. 3506

,1J'

All these values are for the l of the Structure. Stresses must

be ,computed for the 1/4 points. This will be done by multiplying the

individual cases by the proper ·coef!icients. Stresses are directly pro-~,., "( ' l

portional to the moments:

A

I ! ' ! ' t ' ' ~ ~ . ~ ~ i • ~ ~ ~ '6

I ·Uniform load.

At ' ?" ~ I ~~"" At 1/4 .·. . M = 3/4 110 points · ·

B

' Concentrated load A 0

At <i M Mo --

At 1/4 M 1/2 M0

--points ,.

C I· i J. * i l J l + t i Sinusoidal distribution 4 0 I

(correction laad) /'I;

At ~ M - Mc -1 At 1/4 M - \[2' Mc -

po·ints

11)

for A·

.•·

rrl/4 points= 3/4 ao + 1/t/T <1c

d.1/4 points= l/2 ~o + l/v'f' ac ·: for B

-15

"'·;._-.,•--'•·····-~--~•1,- ,, . ., .. .,_.,,_, ____ .... __ .......__, -·----•·n~-.•--------------...-,-·__.,,,_,_..,_ ______ .. ,,, ,-, .. .-..-- ·-··t. •, • · . .,._._ .... .,,... .. - · -· ·--:t·· ... .__,...,. •-·-" --- ~ .· -:....:...--..... _,..· -,..,.'. _;, ....... '•-. · '• :•-+• · .. • • -•· -· ·-- --- ,_-' .. _,., '"".: _ .• • · _---i,,..-,_~---• :~·•_ •. ·~· .. --i.,~ .. _-~; .. _.,.... _ '"~~--u,,.. ., ........ ~ -..- ,..._,.,_ .............. .-... -..;,-,t,~ ... , .a-~·-·>--- __ ._.,. ... ,. .. ,,.,., .. , .. ,,,,. .. . ... ~.... . ... - " . . . ' -. . ..

f ··4 I ~l ·,:Ii

..; . ,,:, . ' ,.,.. . ·.,. ·'-

Page 24: Study of folded plate structure

,.- .. ,;

., . - - ~·- _... . . .. - - - :., __ - - . - '

C. - COMPLETE ANALYSIS FOR ·rHE ELEMENTARY LOADINGS

!ABLE 2 PLATE LOADS 1. Plate forces

Plate :/11 Plate fl3 Plate/JS Plate 17 Plate 19 100 100

5 7

i

1 9 us .Q

100 100 ·

~ ' US I

U A I

. ,

C S

CA

t1000 + 1000 f 100 tlOO ·

J 100 r .\·

N S

241. 421 ' t '

NA

;r.

100 ~

_,

100 ~

_/

0

141.421/

1000 f

1000 t 0:

100 J, 141. 421/ .

0 0

:_Q . :. -0 .

o 14L421 \

o .

;Q :o

a 141.421 '\

100 ! 341. 421/ 482. 84:t-° 341.421,

100 i

0

100 f

0

10.00 t

tooo i

100 i

100 t

'\,--16

'4,

_ .__.__ _ _., _ ____ _ -·- _ , _ ·-,. _ .. .._., .... __ . _ ... , .. " .... - ... ·. -:..;.~.._.. --.-.... . _.,J ··~ - .. b . ~· •• -~~{' --.. ... _,"":"_'_'="'" 1 IS .,_.,~,- -:-',,....-· .... •.:..~~•: ... ---.,-~ •• - ........ .,.. ...... _._. .... ---~•·-:_ ··-··~--·, _ _.__.,·_._:,.. .. -~-.-..... ~ .......... -:---·....., --::-: .. _, ._•1111"1'~~,-.-n:;t,....:_r .... ,""'.',~, ..:..-.~~Hr: ,,_ , m.-.,i,~,~..a·~~,ff ....... "l,:;i,~.;.-....;:,:,..,c,·.,:-.n -~- _ ,. . ~ ,,

Page 25: Study of folded plate structure

•' \ '

I f

~17 ···-··~ ___ .. __ ., ..... ,1 .... ~- ·-·· ....... ~... . .

-~ .. ···-~-~-. .-,.~·-··.-""' .. -•.. -.. ~- .. ; - ... -.-~·-_ . . -· . .--.·-···: .- -·' ·, ·.... .... . '

TABLE 2 PLATE LOADS (continued):·

Plate /11 Plate 113 Plate 115 Plate ./17 Plate 1$

0 141.421/ . 0 141.421, 0

T~S

."1·

\_

.,

Page 26: Study of folded plate structure

' ;

.. ,. ..... -...1. ..... ·.

--·······---········-·-··-·--·.~. ~--·--·--· .-··-·-·-·--,,-.-- _ ....• _..-,-._--· ' . ' ------·- 4 0 - ·--- - ,_ 0 ._ ..... ~ 40 ... -- -·

...

\

-

2.. Moments in Plates Due to Plate Loads

The plates are considered as simply supported beams

bending in their plates.

(~) USO, USI, UAO and UAI are uniform loadings.

(~) NS and NA are ''Normal loading" (this is defined, p. 1~)

(r) CS, CA, TS are concentrated loadings.

(a,)

...

J

,. ·--:•

i

= f X (L - :~) 2

(() . Met

M

(+) if p (4-)

' . ·,

(~)

PL =-4

PX --- 2

,- .

j \'' •

-~-: .: .. 1 , ..

.2 = 90

9 .8.7

= 90 12

i ~ s n -9 .87 L f

._,

-()·

-18 · -·

J

Page 27: Study of folded plate structure

-.~. ,_.,., "1 ~ '.:._·-;_,, ' ', • ",--, •, ., ' ' 1' : ,• > - , , • ' •

I ·- -19 .. j -·· ,,.

....• ,,, .,

r··· .. TABLE 3 MOMENTS-DUE TO PLATE LOADS

K10 M30 M50 M70 Mgo

us 0 + 16,200 <

16,200 -

us"-- ·+ 22(~ .. 910 + 22,910

+ 16,200 U A O + 16,200

U·A I ·+ 22 :9·:io - 32,400 + 22,910 ' ..

C s - 9,000 + 9,000

CA. ... 9,000 - 9,000

:T· $ - 12,728 + 12,728 ,,:

.N S + 13,130 - 18,570 + 18,570 - 13,130

NA + 13,130 - 44,829 + 63,397 - 44,829 + l_J, :130 '; ..

'

.a,,

. ., ..

Page 28: Study of folded plate structure

,. 'Pt . ,,,

fl

~. .., ....

,;;

"'·

. ..... _ ...... "'- .

:if ' .

3. State of Equilibrium of the Structur·e .. ct '

10---------------------i

,,: ·w~ -

..

9 . } Mgo 8 '"'-----:==----t

Ta a--~zd"'===---~

' ) M70 7 6----:=::----; >

T6 6

,,

5

>

T4 <

3

>b

4 .-----!:==------J

, ) M30 2 ...__--===----,

Tz < 2 ----!===:..--...J

1 I

' MlO

0

\, y J

Tz ) Tz 'd. .. _,

2··

·a ... 76: •..

(l_f():

·a· -·· ... · 78

0:1_2:

. Exa~p:'~e .. : n·etermina tion of the stresses Plane Projection of ..

the Folded Plate "'

Mso T6 T4 T6 + T4 - d Structure + ..

~54 - -= s z A s 2 ' ' ~

M30 T4 - lltwi T4 + Tz. d + -:C134 - -I z A s 2

By ·compatibility a = er = cr 3:4 54 40

The fore.es .T's are the solut~n of a system of 'simulitaneous equa..ti'ons :

!_ = 4 Tz + r4 25 · ·

~ = Tz + 4_f4 + T6.

A (M50 + M70) - T4 + 4 T6 + TS - -25 ~

(M70 + M90) A - T6 + Ts --25

q -

-20 . . -·-··-·---·, ....... ~ .

I

(

Page 29: Study of folded plate structure

---------------~------:-,-~--:-------------------------------------...... ----., . . I I • '

. .,

.... . ........ ~- .. ···••·. . . :::-. .:. ..

,. t;

\. "~ ... ,~

~ --

............ ....... ~ .... ~.· -·~ . ... -.,,.,.,,., .... •'• ..

I}·.·.

': "-'-' :- •' -~- •' -4. Non-corrected Ridge Stresses

A 2S

A'

M10 + M30 .. ,-.·r, 4 1 0 0 T2

M30 + M50 1 4 1 0 T4 = -

M50 + M70 0 l 4 1. T6 ..

M70 + Mgo 0 :0 1 ,4 Ts

T2 , T4 , r6 , T8 may be expressed in functions of M10 ,

K30 , M50 , M7o , 'and Mg O wlii-c h are known.

I By replacing into the expressions of a, Ts by their

' values in function of Mo 8 , the stresses can be written

as functions of the known moments only.

(160

0100

...

+ 306

- 194

.... ·+ :52. . -

- 14:

. ·+ 4 ..

... 2

- 82

+ 164

- J-5·6

,+··-. - - 6

+ 22

·- 4~4

• .L:54

+· li/+-

2.2:

Where ·A 1 = 348. 33 A

1 - = A' 0.0045933

-..

..;.-.

- . 6·

+ ti.

'• 164

+ 82

+ .2

-,' .4

..... ::52

+ 194

- 306

-21 ·-· . '" -.... ,, ........ .

' ..

Mgo

Page 30: Study of folded plate structure

' , ·-·.-../

\ '

,:·

·'I!" ~

• ~------:~ --,"r"-. ~•"I""~,--~,-,, :::;-;o;,::.,_·;_:,.,.r-·,... ·~.::...~-~ ...... ..,_ •• ,,., ~ ' ,, \ • .,, <•r-~ I•• ' ~-

-22 ••••• io ......... ___ ................... .

' t

. ,: - .,· - . . ~ - .... . '-... • -·- .• . J, . ............ ---1;.· ··--------· ..

This can _be' simplified since ·the particular loadings are

all either symmetrical or antisymmetrical.

.~

.• •· .

000

,A'

000

A' 0 20

040

,, •

For

+ 304

= - 190

+ 38

syounetrical

t6

+ 152

- 114

cases:

f I

MIO = -Mgo

~o = -M 70

M50 - 0 -

0 00 = 0 100

0'20 = 0 so

cr 40 = 0 60

For antis,ymmetrical cases: M10 = Mg0

+ 308 - 88

- 198 + 176

+ 66 -· 198

+ ·22 ' - ·44

+ .154

M10

M30

M50

j/-

000'. ;: -·0100

(1'20· = -(180

Page 31: Study of folded plate structure

.-·,:-----•. . J. . . '

•. .#,-f I._~ /C">"'< • -23

,,. •lt,-4, .. ,• ... · .., ....... ,~

,',•. ...... '"'1 ............. ·•••· .• • "'••-• ---• -· •• -··· + + + - 0 + •-• ••-••• ••••••0 .. +Lo.4 o-.1-L ......... -•+•• .. --'•••Oo+O•+ ··-··-·· ..................... +04---'0 0 ··-

_ ·---••u+ ·' "- _ --,,,.u· - • • •

r

TABLE 4 NON-CORRECTED STRESSES FOR THE ELEMENTARY LOADINGS

Solving for the different cases: ...

~ <S

aoo + 22,621 36,759 -u s 0 0'20 - 14,138

+ 16,966 cr 40 + 2,828

0 ;, ~.

er 00 - 7,998 23,944 +

I :U· .,$. I er 20 + 15,996 27,993 -! ·,

C140 - 11,997 l )

0 /

.. u A 0 croo + ·22 ,919 37,653 -

a 20 - 14,734 ·+ 19,645 0 40 + 4,911

9,822 -"t ..

12,535 0 00 -~

+ 3 7,604 u A I 0 20 + 25,069

- 68,824 :. ;.:-.

0 40 - 43,755 + 87,510

cr · .. 1.2 ;56 7 ' -o.o: + 20,421

:c-s-:: er · + 7,854 ;..; ·-2'0: 9,425 -

0'4:0-. - 1,571 0

12, 732 ~U-"!"

0 00 -+ 20,917 •

CA a- . + 8,185 20 -· ,10 .9:13 2,728 .. · . ' ....

Gt;iO + .5.,-4.56

croo + 4,443 :13. 330 -·

8,887 ... ' ' - TS cr20 -J

+ 1-5 ,5S2 Ji

r

6,665 '

0"40 + ' 0

{

~ I'

:~ ' '

24,817 i

000 + t

49,241 · ~ -~

t NS 0 20 - 24,424 ·:.. ... .-f

~

+ 36,440 0'40 + 12,016

0 •

",

j 000 + 43,103 ' -104,098

.~. ' ~

0 20 - 60,995 •..

+150,592 -~-' 0"40 + 89,597 -17,9 ,194 ~

,.

:-

,,..-,,. .

Page 32: Study of folded plate structure

- '. ·.~·· ·.·: .. ~ .... ,,,,.......,.. . -~-.,,... ........ . .... .,.

...... ,t

These ridge stresses are not the-.final ones. The joints

deflect under the load, inducing moments, the reactions to which,

at the joints, act like additional ridge loads.

These ridge loads are not uniform but vary as the deflected

shape of the joint since they are proportional to the deflection.

It is assumed that these loads vary like a sine curve along the

joints, which is a very clo~e approximation of .the deflection

curve.

~o ''Norma 1 11· load

! ~ = io sin

2 goL :-1rx:: M :s\:i:n

... -- 9 .·87 :L·.

. n.i - Mc1 • - sin ·1.

M

L

:~

-24 -- -- : . •.• ... -

\ ...

ii .

..

Page 33: Study of folded plate structure

I

' I . I

I I

•. J

I I I

I l

I I I I

. ! I

I I

I

' I

! i i.

t r l I t

t f'. R ! .:,. f !·'

--·~ ....... .., ....

!

A

ii

,-~--·' - r--,' •' • --· ' .•• ,-~ ,,, ''"""-~· ' ~

,,.,.(,

-25

0-, 7. ·~.

5. Deflections of Joints

a. Displacement of individual plates.

p L4 Met, L2 1 J • ~ I j i • l

76.8 E I 9.6 E I

! p L3 Met 12 -=' -0 -

48 E I 12 E I

L4 s 90 M(a. L2 i ' i i + • -?>n b - =

97 .4 E I 9 .8 7 E I

2 I a Mq, -- h

Acr A a 2 I 2 I Llcr 1\ - = - h h

)

8 IAcr 12 1 ~a L2 with' a· E s Thus - = X X --

' .. ' - h ·:E I E K h

For uniform loadings .8·'·· = 12 ". Ao

h 9.6

d cr 12 h 12

For concentrated load _g·f.' =

.,

A a . 12 h 9.87

For normal loadings $' --

,:

.- .~ ' ·-.. 1,. '4·--·· -· . - - . -- -

Page 34: Study of folded plate structure

• ... .. ,.

..

-26 --..,.,........... . .. ' .- ...... ;, .

- -::- -'.----------.---... ·----·-·· --.----- ··--·------ ---··· ..... ······ ·-·· ···--· --··-----) -·-.- . --· ... _ .. ·--- -------·-···. -------- - ·-· ·--(

Ridge (K + 2)

. - - . --.. ·--···-·-· . .

!:'

SIGN CONVENTIONSP

~• (2K +

Jidge . !'(K + 1)

l-J A' (2K + 3).(2K. +, .iJ i'is positive if the deflection

occurs from the ridge 2K tow­

ards the ridge 2 (K + 1)

~ 2(K + 1)

Ridge 2K

' ' ', / ' ' . '

- - - - -- - .... -- - ~

A' (2K + 3) (2K +· l!J): .A' is positive if directed towards

outside of structure A 1 (2K+ 3)

A '{2K + 3) (2K + 1)

Initial plate position

-----w Final plate position

A '(2K + 3) (2K + 1) = (2I( + 1). 2- (2K + 3)

A' (2K + 3) (2K + 5) = (2It + 3)- (2K + 5) 2

~' (2K + 3), = (2K + 3) "(2K + 1)

, ..... ::. . .. ~~.- ..

- (2K + 3) (2K + 5)

A' (2K + 3) 1is positive if the

rotation is in the clockwise

directiom

A1 = ELi

·i I

Page 35: Study of folded plate structure

' ' I

• • • • • ' ,• • .:.. • I• • • • - • ~ ~ -•-

' . .... • _.,:. ___ .......... _, '-# ·-

TABLE 5 DEFLECTION OF PLATES

According to these conventions E fl.

has been computed for each case. _

" ·us o

U: A:O

u A I

:c-s·

-·CA

TS ..

. '

NA

PLATE

1

3

5-.. :

1

:3

.S-

1 3-

=s-

1

3

5

1

3::

l

3 ..

5:

"

3

.5:

].

-3.

5-:

1

3

5

8'

- 992.5

+ 458.1

0

+ 647 .8

- 755.8

0

- 1d16. 6

+ 530.4

- 265.-2

+ 1015.3

- 1858.3

+ 2362.8

+ 441 • 1

- 203 • 6,

0.

+ 4.:5'1 .8 '~ 235. 7

+ 117 • 8

·- 28 7. 9·

+ 335.9 -0

-.- I2.9-3 .... ·i +- 9·56,:. 9:

Cl

-~- 2733. 6

·+ 3954. 5 •.• .....6-1

- 4705.6

X 103

~-

,·.

.~

.. ~ ...

- __ ·A_· -f_: = L,l

A' X

0

-- 2320 _Q:,

·o· :. '- ·_:

+.· :24:28'

·o-

o - 2873. 5

+ 2030.6

+ 8488. 5

- 9981. 6

0

C + 7036

()

·o +:, :12.76 ... --9.

- :9.·0·2 .• 2

0-

:J07<). 0

.0

0

:3,..742·-. ·.5

·o,

0.

..... 18,429.6

+ .. 20,596.2

103

-<:,

!

: ..

·---~--~- -"Of,:,.__.,'.!._ .· _;:_·-:.,,,r.-1...: .... ~-,..._ 'f.., "~----' '.._., .. .-~- ~-,,~~"11<•-f: ··- ~ :c-____ _.,..,_ ....... .,~-.... ,. ;_'A.-'-' ........ "; ;,.hrt,..··· •. ,,., ••.• ·-· .. - .4_,...,.. \i"'t •-:::---~.. -. ~ .. ·.~·:.,,,._ ~-"!'r •·::.: -,l·~-.f -e.-+-,:•-: ;.• --.-._ ~-...... ~~~ , ... ;;,.·:.- ,_--.:. :;.._:-.~~~ . .,"!!,,~ ...,.._..,.--;1...--...,.-p.;-fL, .. ..-..-__,:- ... ,~,u,,,¢.a.-~,..,=--'--.-,~,...,,,,_'(..:,,, ... 7,...,_ ~"~ : .. ::--Ai·..,.,. ,j.·:--- ,,,..;·-.._.-.f.1:..i-.,uc~-•...:!~,.;...,u.t.:."1~,T·:..-::-,~•.._,11......,,1;;:.~.-;.:ii. ... ~ool.• .. •-·-.,- , ·1 .. ... ......... . . •, .. .... . •'•. . . . ..

,'.

(';

' :

Page 36: Study of folded plate structure

1• •• , ............ _ ••.•. ._, < ,,,,.. -~ • ........... --:.· ..... •,.,·, .. •' ,·, ,, ·- .; ...... .• . .

6. Induced Moments . ~:

.,··

{

---

- ·• . -~.

Fix~a End Moment M4

-

rr, .... J .. t~l1:_.:.,.... .... ! ._ •. _ ,.·:..- ..:---y·· .. , .•..• -..· . .,.,i.:,-- J-, 1: ,J""-·-·· .. ~ .. :.-~-,":.-, • .._:._ ... _ .... .,_ .... -- ..... - • ..t•--~ ... __ ........ ,-,_, __ ,.;,: _ .,,_, .. _ ..... ...... 1..J.

·- . No ~r·estrai·n:t ________ _

.. 4. 6

5:

.5.11 .. • ,. 5/V2 II

. . : . . . .

·._lrt· ca·· ·s-e__ o-il= · :1. symme.try'

In cas.:~ o·f anti-symmetry

....

:li:o

8

: . __ ... _,' · .. _- .. _·:_ ._ -:·.-. - -....

rr

Und_t{t- ·~l¢t-t-f c-a.l Lo.:ads•

. . I M43 = .J <l2° E .43

M45 ·= 6 -1 E.15 d2

Rz = ff -5

= {[+ 1.. 5 2.5

~ .... _ .. , ,., .. ,,\~--.,.,,.,., ... _ ... ____ ,

• • , •., •,!'•, I'•·,.,•.·•" "'· - ·", •. ,· ',,~ •'·.

-28

.......

.,,.

Page 37: Study of folded plate structure

I

• I

.(

' .,. ' \

. 'l

, ...... ~>-·-"·

1, .•.. t .. 1-.., .•• • ,.

. . ' .............. •'

.'(,..

> I • .. ,:.<

I.

Distributed Moment M4

.; . ~ ..

. ~- .

) I

In case of syuli1let:ry

3/5'2/5 I

I

2/51 3/ 5 I

·M·· ··3· 4 . .. . · .•

I-n cas.e. of· .an·ti.s.ynnnetry

,

1/.} i

= 3/2K__, ~ M I M

451 .43

., 2'/ 3. ,j

1·-

..... : ... .., .• -... ;. 1(

l-.,

-29 l \ . l (

l ....... --............. -... -• ..... ~ ,, ·.-:~

'--· .

. ,,

..... - ... , .. ~ ... <;. ,..,. -?--"' ,..., ~,.,.., ,.· ,, -, -·J ,;..,··, .... ,. ,,-~ ...,-,. ,--~,io .'~rllt.• ,,,r,-~----r-.. 1. -~

,.. . . <' --;--r:!:'.- l ~-~ ---' •.;;. ..• ..,..- • •-~~.,,_......,,1-.. ___ ;-_ ;_...-6:.,.,.,,_, ~•· .. ,.......;- _,..,,.;,,;·..-~ ,_.l,f.,.,., ,-~_,..._;_-~ta-•-..,"",'-...,,~,.-•~-~-·--=..:.-•·'~•-••"""'-... ~- ~ ... ~.,. .. ~,.u.,..,...._., ,µ.j,,', •. .,..._.lo,c;.1,y.•.-Q:;.;.t.t.••·"'·~:-,"'-•ir.f!'T"-... ..... ___ : "".· "--'_ ~-·-r.;:cz,,··x:n,

• - _, - , ...... • ~' ..... ,,, • -'-.l~"". ''. - .. .,., .• • ' ..

Page 38: Study of folded plate structure

__ ,..l . . •· ....

t\

=·it '

"

...

..................... ____ .... _ ....... --.

. ':'. ~(

...... ,, .... . . ...... ,1,, ..•.

. '- ""Ill· ~ ,.,

. ..... : .. ·•

From the Table 5 the values of rn 4 are computed:

US 0

US I

UAO

UAI

cs

CA

TS

NS

NA

I ' .

TABLE 6 MOMENTS AT RIDG~ 4

m4 Fixed End

- 45.3096

+ 47 .4188

- 56.1194 + 79.2055

165. 7706

-389.3420

+ 20.2330

+ 24. 938

- 35.191

+ 2.1 .• 0 6-5()'.

- 73:._091

-359. 93008

+804.48751

·!

m't Distributed·

- 18. 1238

+ 18. 96752

- 63. 8144

+240. 294

+ 8. 0932

+ 28. 3556

+ 8. 42915

- 29. 2364

--sos: ... 1.fsg:

;.:-

/

. ,

. . .

·'

..

..

;~··

( --·-..-··- .......... •-,--·--·' ... _ . --· -- ~, , •• , , .... _.-.., ... ,,,.,"- -·•, ... •-..::r ••••• .. • · ·-·..a•- ·--~---· .,._....,~_..,L,.....---..--.--,,..-.+..-.,,,.,,, _.._ ,, t...-.a~ .. ,r--v•,·"- ·• -···

-:)

j ·~1

;

' j

·'

Page 39: Study of folded plate structure

I l ' I

,, ,, 1 ' ,.

,1 z·

,1

........ ., ' .. ' ' . .. . . . •' . . • j

.... ,.

.• ~~-t"·~··=-;-;,-;>·r~.-.. ;,~1 .. - _- ... , · - •.... , -, ..

/ .. , .. ,, ... " . . ... •' ·,~ '. • '•.- I ,A ...... : ... , •.

- . . . ... ,_. ,., •• '·-· • k- ...... ~..... .,,,

• ,, • J • ,.;..:., .... ~~- ... ,. . ~ . : ,.J

7. ·.Secondary. Load-ings

Loading

US 0

.-1_~ ...

U S I

tl AO

U A I

C S

.c A

TS

NS

NA

They are the reactions to the moments induced at the

joints 4 and 8.

Symmetrical Case: Rz = Rs

R4 = R6

R2 = - R4 = M4

( v;-) = M4

(0.282~~;8).

R2 = - Ra ~

R4 = - R6

R2 = K4 ( vi) 5 =~ (0.28428)

-.

R4 = M4 ( {i ~ . .1.) = M . (2 + '\12.) 5 5 4 - 5

·~.

R4 = M4 (0. 6828428)

TABLE 7 RIDGE LOADS EQUIVALENT ro THE POINTS DISPLACEMENT

' R 2 + 5.12618

5.3648

+ 18.0494

90! 6 7. 9654

2. 2891

- 8.0202

2.3841

+ 8.26930

+ 143.717

' Rt+ - 5.12618

+ 5. 3648

-· 43. 5752

+· 1'64. 0830 ~

+ 2.2891

+ 19. 3624

+ 2.3841

- 8.2693

- 346.963

~s = 100 + 8.2693 = 108.2693

~NA -:~ , .. 100 + 143. 717 • 243 • 717

' R6

-· 5.1-2618

+ 5. 3648

+ 43.5752

- 164.0830

+ 2. 2891

- 19.3624

+ 2.3841

8.26930

. + 348.963

' Ra + 5.12618

. - 5.3648

... 18.0494

+. 6 7. 9654

- 2.2891

-+ 8.0202

~ 2.3841

+ 8.26930

- 143.717

-31

I

I II

~ V ~ I t~"' , ~ - !

< ~ - ": • •• ~~, .. r•., ... ..__:__..,..,._ "- ~·"1· •"""·t1•t::Wl~c~·,,;..--.... ,t. ... ,~r1.. .. ~~·-·"·'-'. ·--- ·-·- 1.._ ..... -., ~ ~ - ....... ..-.._.._._..~~- .;:11·,w,1---..-' -·~- •t.'11- ··~-. ,........,....,;.,.. ... ....;.~·1&----ii ••• ~~ ...... ,.~ ..... --... ··--·.:.. ............ -.,~ .... ':Ir_;, ~-·~~ .... ~-· ,, .......... ". ,.,_,_...,..r, •. ·- _ ......... , ..... .,..._! ... w,.,. • -.-:q.-..,····•'Lt'IF".:r -·a.-~,_ ... ._._ .. -... ;, ..... ·!'\,.,,-.;,;.,.... .... ,~J".• - ·...-, .. :;...... .......... -A.'."""t,"!i'•~•·-~ .... r.·-...,~.~"!"~ -....4 ____ - -~-----· - - ··- - - ~-· !~ - '.

Page 40: Study of folded plate structure

-. V-

I

l ' i ' Ii

~ $ ~ ! .~;

~ r I• i' ~ f ), I ~: .. r

t )j ~

f ~

i i i, ;!

~ f. f,;

~

t ~-fe

I

·-

-....

The initial normal loadings (NS and NA) and their respective

-corrective loadings have- ,the same shape and are in the same ratio.

As a result the computed stresSes crNS and crNA are due to:

A =(R ... R')NS or NA

R is the actual ridge load.

The cod:-ection to be added to the deflections fo.r· the·

other cases will then be: R + L Ci (loi.dinCJ i)

TABLE 8 STRESS CORRECTION COEFFICI:tniTS

Correction Coe·fficients for:

... '

+ 5.12618 tr S 0 108.2693

·u ·s I 5.3648

108.293 •.

18.0494 UA 0 243.717

UA I - 6 7. 9654 243.717

C s 2.2889103 108.2693

1.02017 -C A 243.717

T S - 2.38412 108.2693

::: + :O= •. 04 7 346 NS

=0.049550 NS - ·--

·+· 0.0 740588 - NA -V

-~ :.- 0. 2 788 701 NA

+ 0.21140898 NS --

-- 0. 03290 771 NA - -

0.0220277 NS - --·· l'·

TA None -·Always Synnnetrical

---

..... .. , ~

Cuso

Cus1

CUAO

CUAl

Ccs

CCA

CTS

-32 · . ······-a,),.lo-. ••; .,

Page 41: Study of folded plate structure

"

,..

... ,-

'.'

..

"

I' ~ · I (. rl •• ,.,_ ....... , ........ ""~" .......... #•' ·:. . • " .. ~ -·· ...• "''~ ............ .,. ........ ,.

' •.• •.•,1111:.1.,._..._., .• .., ••• , •-.-:·:~, 411•,C' !' ,........__ · ..... _:_~.-~QI'~~.~'· ,t : ; . \ ~

.,. ... , ,...,. ...• "'....... .. . . ~

. ··•' ..

D. RIDGE STRESSES WHEN ·rHE H)DEL IS SUPPORTE1) BY INTERMEDIATE

COLUMNS AT MIDPOINT

The joints stresses have been computed for the simply supported

model in the three ·cases of loading (Table rot\ !?age 69).

The joints stresses for the theoretical syunnetric and anti­

syunnetric reactions :. only (of 1000 units) are also known (Table 4 ) .

The joints stresses of the model on columns will be determined

by using the principle of ,ruperposi:tion.

Assumptions

a. Define the reactions in each case.

b.

c.

Define the joints stresses due to these

forces.

Add these stresses to the stresses of I

(

the joints when the model is simply

supported for the corresponding case

of loading.

Deflections at centerline of ridges O and 10 are zer,oe

The reactions of the columns are considered as external

forces acting on the sttjlcture •

".

. .

-=-· .:

...... --· '·-•~ -,1,_,-,..·.-a. ....... :.·-'"'-. -·~··.~ •. :. : .... _ • ..,_ __ .J ,.,.,. • .. - • !. - ,.:: - .. :_ .:..·--; . -~·- ;_ -- .-

". -- •,.·.. •• ,o, ..,_ ·,.>" -~ ·.-•• :-,~o.pc. " c • i. -.;,, ·."c.-, • .=.,..,-.~·~···•""'"~'-'--~~=-·· : . ..;.;.~-~·•"·•·•·•..,w···- ~-,~-"~"-'····~<'-· CN.·,• •=~~•""'---~~-,,.,.. ~ --~···------. ,.-,·m~w c. - , . ..,;,_,. ' .• ~ • -·~,-~,......,,..;;_.u~~·~-~··'· .. ·' • .

. ·-·· -- ........ ~ --····· . . ........ -.... --·· ' .. ,

"'

I -

Page 42: Study of folded plate structure

- I ,I

--~-

-~-

1. Reactions due to\ the columns

1 9

If the structure is simply supported deflections ·of the model at the

c.enterline for the free edges O and 10 are:

and

.tt:'

· b. 0

= deflection of plate 1 = 6. 1

-8. .· = deflection of plate 9 = ~ · ··10 9

~ ~

C 0 = Kg (synunetrical load) + KA (antisymmetrical load)

c10 = K8

(synunetrical load) - KA (antisynnnetrical load)

.c0 = Ks x 1000: +).CA x 1000

ClO =K s X 1000 - K x A 1000

I

then the corresponding deflections are • •

60 = Kg (deflection of plate 1 due to 1000) or K$~1 S -

(deflection of ~

1000) or KA~l A + KA plate 1 due to

:i6. ·10 = Kg (deflection of plate 1 due to 1000) or Kg69 S

;),

1000) or KA6g A + KA (deflection of plate 1 due to

.,

•O

-34

·'. .. -- ''!, .. •• - .... •(· .• . .. ~ ... ·i--; - ····-z-·· ... ' ·~:1.'!: ..... !, .,.. -~ ·: - . +-.. - :· • ~--·-,- .... , __ ---·· ._. - ...... ;.,..•" •i,,- .... ±~ .... ..,.._,__, __ •••• - •• ~ •• -, •••• ~-·· •;. ' .i...• • ... , ,; • I. ' ·-;, ;,!'

.1

Page 43: Study of folded plate structure

I \

, .... , .

' . .- .. ,._: ....... --.~---.·-·.~-: .. ··• .,:~:.- .. --· ... - .· _.-.. ··.:-, .... · ...... -··.··.·- ... -~· ........ -~---- -·-. :------~~~-

L i'" '· .

By compatibility: I'

fl. 1 +Ao = o ~ 9 +A10, -= ._o,_,

A 9 = &g A 9' :s + KA A9 A

A = K · 9 S A 1 S - KA A 1 A

• ' !:i 1 A = - fl. 9 A

Ks = A-1 +~. 9

2 ~1 s _ ~ 1 - A 9 - 2A 1 A

t

Are the solutfot;ts of the system "bf equations.-

The reactions are then:_

~ 1 · + & 9:· . ·~- 1 --·- A. 9 + ·· ..... · .... --

-

• _ .2 .. 8 1 S·

81 + ~ 9

2 81 S -

:2 -~-.- A .· .. 1

~l - ~ 9

2 ~ l A

·1000

1000:

•..

The computations will be ma.de using the elementary loadings

(tr'S I, U ~ O, etc.).

The deflections A 1 and A 9 in each case will be obtained by

combining the "elementary deflections" (Table 5 ) . ..

--~·-

··. -35 41

- --~ . ..:.,··;.; ·----- -.. :·, .. ~ .... ·-·-··-·--·-··---· -

' · " •. ·' . ~ · . ·- . ",. · ~ ··-tr~ f": -"i".,;,:'-',, ......... : .. ... •. ,:_ .. ·,- _1. ,,.,-11 ··- ... ·-""•"- ..... .._ -"'=''''.!~--t;1•'1-.... ~J-' .. _., .... _. ,r __ •,:,.<J·"'" , .·- • 1.-, 1 ,.,, _, &.-ui- ,1.-,::i • .-. -· , ~ ,-l.; ""~-··.;;,..-,a..;.•• ~ ... ...i._ •• -· -~..,- ·-·--- ~ .i.....1:.-...;_•1:....· r-• .:.l-l·-~1....1.1~-''~--~-- _.1.- ·--..;.•-~'-{J., ;..-._,m~.-·.:,_..ll.~:...; . .&JT_J.U.:C..L --···- ~~- •• -,..;.,. •• , .i;,t.a .. t 'IS~.--- ~- .,.r;:a'. •-· •. -;. -f ·1 ,,..,__ ~s·1.•,, _ __.~, ·• ' -~,.:.;._. ·--v • • - ,1,,.. ...,- ,.

p· '

1-,,' '•.· •. ·.,.

Page 44: Study of folded plate structure

..

··-····- -····· --· ... ···-- ·-- -- ·--. ·- . ··------ ~-···-------·.--.... -,.--, ... _ ..... ,_ .. _.. ... -....................... ,,.,,.--.~--·-- ..... ~ ...... , ---, .. , .. .,., ... -,.-~,------~--··"-~-~-----·-·-------~--·- -- .. ····---~---~----·-·-····-~------ .... ., ......... -................ , ......... ·--

-· '~ ., . ~~

. " .,,, ,,

- ., . .; .. -·- ~- .;.~ .... -..

Middle Co ltunns

-,_:

Deflection due to load

~ L = - 0.106065 x USO

+ 0.606065 x USI

Loading (1)

~::

t \()

+ (( 0.047346 X 0.106065 ) + ( 0.04955 x 0.606065 )) NS

By sy11w1etry,

\

~ 1 = 6. 9 = + 105. 269

\

t ·.1 •

+ 392. 609

- 45.326

. ·&.,l = ~ 9 =+ 452.552

..

Deflection due to reactions

~ c = - 0.0211409 x KS x NS

+ 1 xKSxCS

By symmetry,

6. cO =~ clO =· + KS x 441.100

+ KS x 27 .337

Llco =flclO •+KS x 468.437 \,

·,

By compatibility•

+ 452.552 = KS X 468.437-

solving _for KS KS = - 0.966089

. ~-··· I

. ........ ··_· -;.;J6. . ~-

Page 45: Study of folded plate structure

·~ 1

~-

. ' .... . . . ~ .

.. •· -~- -·- ·- ·----· -- ... -;-"7""····.-. .~~--= .. · -··.~--: ___ . __ :_:_ ______ .._, _____ ·-----· -· -· .. ..... ~- -...... -·-· .._ .. - ..... •··-- ... - _,_ - -·~. -·=c--.,,;.. .··,._~·- · ... · 1,,, ~-- •.•• . -. . .

.....

}li.ddle Colt1111ns

\.":._;_ /

Deflection due to load

6_ L = + 0.5 x (US!) + 0.5 x ( UAI ) + 0.5 x ( 0.04950 ) X ( NS ) + 0.5 x ( 0.27887) x (NA)

A 1 = + 323.90 + 507.65 - 32.04 - 381.16

A 1 = + 418.35

Deflection due to reactions

Ac=+KSx(CS) +KAx ( cA)

._i.- + KS x (' - 0.021141 ) x ( NS ) + KA x ( + 0.039077) x (NA.)

~ CO = KS + 441.1 KA+ 451.8 KS + 41.0 KA - 68.3

L\ CO = KS ( 482.1 ) + KA ( 383.5 )

By compatibility, 1,

- 418.35·= 482.1 KS+ 383.5 KA . - 165.37 = 482.1 KS - 383.5 KA

solving for KS and KA .! '

r··

Loading (2)

·"·

8. 9 = + 323.90 - 507.65 - 32.04 + 381.16

8 1 = + 165.37

f

~ ClO =KS+ 441.1 KA - 451~8 KS + 41.0 KA + 68.3

~ ClO =KS ( 482. 1 ) - KA ( 383.5)

KS = - 0.60777 KA = - 0.32983

·--~ . '·

·-37

"

Page 46: Study of folded plate structure

• J

,,

i

. .. ,.. ·=·~·-···=· --~-~=====·--= . .---=-=· ===~~--~~--"~--... ·~------~-'" ~~~-----!!!llll!l!l!!!lll!!'!l!!"!!!I ______________ _ .,=, ..... ;:· . .,., .... · .. , .. , . ..__.. . . . . .

.. ' 'lit I •

-38 .. . . . . ~. -- ........ .. ••• d •••••• _ ....... ,..

'',' _,,;

·,..,;... ... . .,,.-.,~.::,l••·••"''"~...,..,.,,.:,,,1:h••·• ,·:. 4 I ,••1 •'°',~-~.,._.....-.. ~-, ~ - -- ---- - -·· .--- ·•·-- ·--. -··----~---------··-- -· ... -- ·.·--·--··-- -

.,

... \

'

Middle-Columna I

I 9

t + t0

Deflection due to load

.. A. L a USO X 0.2125 USI x 0.2875

NS X 002125 X ( - 0.047346 ) NS X 092875 x ( + 0.049550)

UAO x Oo 1875 UAI x O. 3125 NA x 0.1875 x ( - 0.074059) NA x 0.3125 x ( + 0.278870)

,•· .. ,-...

b. 1 = - 210.906 + 186.242 + 13.099 - 18.421 - 190.612 + 317.2tl ~ 37 .959 - 238.225

ll 1 = - 103.583

h-. . ..

L0a41ng (3) .

-~-

A 9 = - 210,~06 + 186.'f42 + 13.099 - 18.421 + 190.612 - 317 .281

9

- 37.959 + 238.225

n 9 = + 43.611

Deflection due to reactions

CO and ClO are same,'ifor the case (2) By compatibility,

103.583 = 482.1 KS+ 383.5 KA. - 43.611 = 482.0 KS - 383.5 KA.

" • ,t

solving for KA and KS

- .:: - ,· .:. - ·.::.

... .. . .... ~ .. --- -

'"

: ... !

KS•.- 0.062198 KA. = 0.1919087

.,

Page 47: Study of folded plate structure

~ ~ • , ,, •. , · : ,1; __ , • • 11 . • ~ , ·• • ·,, • • ·,c • · , , . . ... ' "\ . '·. '

.. ·~~-·,,

-~·

'·'

...

'I '.--·-f>

. .. .

~• .... -

2. Stresses due to the columns . \

Stresses and loads are proportional. The stresses

are simply the algebraic summation of the stresses due

to CS and CA (Table 4, page 23) multiplied by the

proper coefficients.

3. Final Stresses

These are the summation of the stresses determined

.above and of the stresses of the simply supported

structure (pp. 69 and 70).

The final stresses are .. ·tab.ttlat.e·d· ·on pp. 71 :arl'd: .72: .•

-~

. .. '.

'r

-39 'P,.--·-- --- --~---- ------.--- -' '

l

. I

Page 48: Study of folded plate structure

'.

-40 1.---·•"'••r-w-•-.,~·- -~. .. ...... -• •IIP.-,l'to • .•• , •a-.-......,•. f• ---- ....... ~ ...... . --·-··•·· - - .... - ........ ..., _______ ... ~----~-- -·-·------~--- ·- --· ··- ---· ··-•- _____ ..._ r ---- -· --·--- -·--------·- -----·- .. ..... ..,....... ···-· - - - •- -11-...1 - .. -~.: '••~HJUJQl'"I,._.,.,,_,.. ___ ~~ --~ ...,.,,,.

---------------- ---- - - -- ---· .. ··-· -- -.,-- ·-- ---·--- --~-----.. - - ·- ., - . - . -- ·-- ---- ·-- --- - - - . -

E. RIDGE STRESSES DUE TO THE I TIES

As with the columns, the ties are considered as external loads,

and the final stresses will be determined by using the principle of

superposition .

The stresses due to a tie exerting a reaction of 1000 at the

centerline of ridges 2. and 8 are tabulated (Table 4 ) .

The actual ties are located as shown in Fig~i J..

36 --

'~. 5 9 - t ~.s - - ~

--------

u

..

Assumptions_

'the length of the ties remain constant. The ties behave as pa. ·2-=:,-..

simple supports and resist the horizontal components of the plate forces .. ,

in plates 3 and 7.

\

The loa<;lings studied here are all uniformly distributed loads, I \

that is, r3 and F7 remain constant along the length.

Since the ties are not at the centerline, a correlation must be \

established between the effects of forces applied at the middle cross-

sectfon and the effect of the •ctual ties. The stresses are prop-6rtional,

Q.· <;j ~ .~~ '•'·;:;.·· •.• ,. -•-.!;--~.-:.;_· ., .• --.;:•,u-'-"t,;, .. -.:-•. .r;.:.-:-r.~r..,-,.·••_..-.:_ -·-:=-:\.,.:,,.....:,_ .... .,:.,·~.:..•,";. ... - ~-•- .- . ....__·,_µ\.~ ·.-;;,• ,• -.... ~~-f-~ .- .... ~~~-.... ~n, ,•,• -~~-~~-- .~·..:;.;.:..:, i.~i,.,_,.._,.:,:;·~-;~·.,,. ...... ~"'fj-'1.T,J ... l'T,•-,·~r,:,.,;:li:"S.• ~ ..__.__,.._~NT:~"•,.,..........,..."'r.a.-:cru,'<..,'U.~AG•~•·:-::i&D.W1 ,.I._.S.._..P ..... ~,~.•~.._..,,,,_..._._,...,._ • .-.1'!'"_,._ ..... ,..~.t,..,.......,,~~=f~,..,..._"'_'~ •

·, -r

i

Page 49: Study of folded plate structure

um

. -

...... ' ., •• ,,, •• ,,. r.>"- ......... , -( - . ,. ...... ... . .... ·····

to the moment due to the load at the considered section. This correlation

will he established with the moments. (

... ,a 18 ,~.s 9

T T

M = TL -4

M - TL - -4 M <t = 13. 5 T

M = 9 T Ml/4 = 4.5 T Ml/4 = 13.5 TX 4 .x3~3s == 9 T

Actual Mq, = 13.5/9 M in the case of a single G:, t:ie.

., Actual M1;4 = M

The coefficients 1~· 5 and 1 will be used for defining the

stresses at the centerline and at the 1/4 points.

The following computation will be ma.de in function of the case

where the tie is applied at the centerline which has been investigated.

·:~·,

Page 50: Study of folded plate structure

Relations of compatibility ;.

...... ;

2

,.

If the structure is simply supported, the ridge No. 2 deflects

horizontally of l12. and the ridge No.· 8 of 4s·

These horizontal d·eflections are nothing but the deflections of

the, plates No. 3 and No. 9 multiplied by cos 45°.

b Z = ,63 (cos 45°)

Let us call _a H = ( Ll3 - tJ 7) (cos 459.).

The tie does not prevent an absolute lateral displacement but

si.nce its elongation is zero, it prevents any relative deflection of #

ridges No~·2 and No. 8. Replace the tie by 2 synunetrical forces

applied to the structure. These forces create synunetrical lateral

deflecti.ons:"

Llt+A8 =6T

If the model with a tie is loaded at the cros,s--:s.ectloq q·( t:Jie:­

tie AT+ ~H = 0, by compatibility~

or T = K x 1000

( A3

.. .

-42

'• ·• u . ·. . . .. . .. · .. ....,,

~--···· •.·~ ·.~__... ~,-~_ ... ~ .. ,;1...,.,l'll~-~,i,.-"!"~ .... c..-:---.--- ': -·· ··'.' . - ·---. _.,.·--~ "'~·~-.----;--··· .. - ... ~---:~ . • ...... . • ~ , ... ..,.~1-e':':...-:r·,,1:!::· _. _- ' t-- --:!-:-.::......:.. .. '" • :.;•J•• • .:,...,-._;,.,..'.""-: ·~.,.:.. ~·:.i,1, __ • ,._;..., __.:. ,-:...:_'.-.:..r-:.!' t-.. - I • ..:.,. ::;...,,-. • •• •~ ••' ..... .,, __ ,-~-~l..i.~-'~:,,r;,::...t....-r~.,·t!~:i.:.a.~.l;MJ("-~t..i.~~~-·~.,o..--...,;..&..:..i.ig .. i,.-,!'l=~~-~-•~.:-:..<•,.._~~._,._.>,lf;'•....._. .....:.-aJ,,-~~ ... ----":'-- ·,:--·--·· ••

. ..,, . .

. \

Page 51: Study of folded plate structure

...... ~,-.......

-43

--- . ------ ------- --~ -----------------~-¥-~~--~---,.

The solution is very simple. The loading has been decomposed

into elementary loadings. An antisynunetrical load will give Li3 - 47 • O,

by definition. All is needed is to consider the deflections of plates

3 and 7 due to the symmetrical elementary loadings which are the only

relative deflections of ridges 2 and 8 .

.A3 S = .OT S

t ~ 3 S = K ~ 3 ( 1000) = 0

K = -

I'

Z.LlJs A 31000

-~--

f. '

-.

·-··,~~·-. ·-··--··-· .. ---·- -.--·-- -~·-..... · ... -· .. '··-~.---~--~~- -· _ ...... ---·_ .... '. --·:.,.;;.,,,-·_ .. · ... -·.--~-----~i:ui~-'.?,L .... ~. ·-~ .. -... ~-"·_-· .. 0:.-· •. ··._..·- .. ~ · __ ·_····k": -·.- ._ .. -

.,._

I·:

,.; .. ~-... "; ..... , ... •., , , .,,;; :...,;.:..,._~- 1i ·.-"': ....... :.:~-· :.

.p ·' .

. . . . -~····-,.,._ .... -,1~,~-.......... , ... _ ...

. .. --··.e ...• ,.. .. , ... , ., .. ·--11•_, . ..,..-, •. _ .. :,·:,.: ... - ..

Page 52: Study of folded plate structure

..

,r

:i ,, ~

l, .,

........,. __ .___ • -·-· -··---- ..... ~4--· -

-44

___ ..• .:.:.... __ ~ ----·-------·---~-----

Ties

.-.

. :: .... :; .-·,

Loading (1) _,

.....

. _ .........

a.

Deflection due to load

= - 0.106065 x USO+ 0.606065 x USI >;...

+ ( 0.004346 x 0.1U606S + 0.04955 x 0.606065)NS

83 =6_7 = + 48.59 - 458.06 + 33. 54

A 3 = ll. 7 = -. 3 7 5 • 9 3

Deflection due to reactions

....

AT = + K ( TS - 0. 0211401 x NS )

A 3 =!::,. 7 = K x 473.56

By compatibility:

375.93 = K X 473.56

Solving for K:

· K = 0. 79284

:"':.,, .·

K'= 13.5 x K = 1.2000 9

·-·· ' • , .••• ' ·• •. •-•·-··-·. 4 • ·• •. •··· .• ,~ _...,~....,, .•• ,0_. .... , .. ,,_• _•, • - ••. , •• ,.-__,, •• • R•"" • _ '-:- ~' -. . • ..... ~,..:~~,J'"I ..,, ,L\.:..;,,i,.,_,1,1 . .:..;\l,.C,1.a~,fo"- ·'"·' • .••. c • ;.•. :1,.:.. •·•

• •. ,. - •.• 1, .... .

Page 53: Study of folded plate structure

,r.

. I

·- , , ..... , . , . ' .......

'

.. "9 .

_, ; .: .. ;.· __ :.., ... - .. · ~ ~--- ··----·--- ---~- _, ___________ ---·------- .. ··--·-· -- ----- -· -.,;., - ...... -. -

Ties

_._ .. ~--------

Deflection due to load

AL = + 0.5 (USI) + 0.5 (0.04955) (NS)

A3 =fl7 ~ - 377.90 + 23. 68

A 3 =A 7 =r - 354. 22

. ,,. ..

Loading (2)

\

The deflection due to reactions is ·the same as for

the previous case

.,

ll.3 =6.7 = K x 473.56

By compatibility

354.22 = K x 473:.5·6:

Solving for K

K = + 0. 748 ------n

I ,',

13.5 X 0.748 = + 1.122 9

, .

-45

- ---· - -- - - .. .

Page 54: Study of folded plate structure

. I}

FR

Ties

¥. -- - ______ ...__ ____ ,. __ ~·- ":_ .. __ , __ ·-- I .;

.... .,..~-··· ., ......... ., ... . .,,, ... ..,..... . ,.~ • • .. • - •" I ' • ,I' • ',• ... ,-.. ,., •.at• I. ,_ .. • • ••• ••::. , ...... ,. "',._.'I . . . . . . ......... .

:. .. ~.-....... . _ :.

Deflection due to load

AL=+ 0.2125(US0 - 0.047346 x NS) + 0.2875(US1 + 0.049550 x NS)

A3 =A7 = + 97.35 - 217.29 - 9.63 + 13.63

A3 =A7 = - 123.94

Loading (3)

The deflection due to reactions is the same as

..•

·fior the previous case

By compatibility

123.94 = K X 473.56 ) .

Solving for K:

·, .. ·.

K = 0.2617

K'~ 13.5 x K = 0.3925 9 '

-46 ... t ••

Page 55: Study of folded plate structure

. ~ ... .. ......... ... ..,,...: .,.., ., . . ..... .. ' . ,., ... , ••••• " •• > • ....

---------- ________...._. __ -...- ------~-------. _ __..._ ________________________________________ ...... _ _....

I ! I

I t

·'·~1 ._, __ ---·-· ·--~ - ......... , .. --··----- ...... ~ .... _'I\" ....... .... :...J" .. • •.

. ()

4. :n· __ E S C R I P T I O N O F T H E M O D E L

A. MATERIAL

Methy1 methacrylate (plexiglas) has been selected as the model

material. Plexiglas presents some disadvantages: the most si\gnificant

is that the physical properties might be slightly different in the

same sheet and between different sheets. Also one must benextremely .

careful when placing the strain gages and when reading them. The

problem of bonding the gages has been solved by using the Eastman 10

Cement, a special agent manufactured by Eastman Chemical Products, Inc.

The procedure for reading the SR-4 gages will be explained in ,detail

later.

Plexiglas has been c·hosen because of its very low modulus of

.~las:.t:i:ci·ty - approximately !/30th of E for steel. This allows a large

deformation for a relative.ly small load and makes the testing_ very

simple.

B. THE MODEL ITSELF

It is composed o·f five- identical plates, a diaphragm cut in

the same sheet as the plate with the structure closed at each end. ,

The bottom of the model is open. The model is represented in Fig.2.

The details of the construction are shown also.

1·" .

. '• . ~ . . . .. --·- -··-~---·~----·· ... --.... ~--- .... - ....... _ ...... -... ', ~-

I '

.ft:.

Page 56: Study of folded plate structure

.-

t,

r

n tj '1 [,

11 .11 I\

T j: :•

t r [! fl

11

t '' ,,

il ~;

_,

ll

fi I ,,

j tr

i~ . ii

I ~

' !· 1· ,. '

J. I·

~.

!

L !

i· ,. ~ ~ j

i

J . rl

i\ j'

~-

-~

-~

·.· _..__,_

:~

Di.a.J)hl:'agml

- --._;,

CONNECTION

, ,,.,

PLATE -

__ ,,. ;

.. ·;; .. .,. ..

.. .. -,

.,,. ./ _,,,._

,

DIAPHRAGM

., ,,,

.. .,, .,··

....... . : ,,. .,.

Fig.

-~-· ,,,

·"' .;, :

2

/ .,, .

. .,.- .

.;:, . ,,_

:.,, _,, .. . ., .

/.

THE MODEL

/. .,...._ ,,,_ ..

--~ /.

-, . .,

: ..... ,.,

-~-

·/

.-,.~

;,.,_.1

/· ~~···

~ ;-'~ .... -: :...,,·~:·- - -- -·,_ . ,., , .,. :, , ., -~ . , ,, ,, ,., . ,,-,., .

,/-..... I

..-: ·' '" I

. .,._ . ;,:·

;,,.

I _I ... lJ: ·.,· . .I:,·· ·I. I . ·1J JJ·· 1 . ..

. ·,-~ ~ - ~. ..... - -- - .-.:~. ,;._ ... ..-_ - - -

.

TYPICAL JOINT

\ ; r l

I {

I I

j t·· I .< ;

l

I I

. I I

- I

.. •

I

I i

i ,

I . .i:,,. co

Page 57: Study of folded plate structure

~Jl~~l!'E!"'-.Y,O•~~, - - • ., • l '1,---,i •J...,"..'•"'-.. t- ;. ;.A'"'"-;;o1,.l.:._,:•~f-tL,d1,,""~•=-', _,•,.:'t'""'-"',,' .. : .. ~,,•('...,',•.' ....... .,.,.1-.--l;:~ .... -':_.~-•~;;t,~', :..-- '"".,-'!,,.,,,

.... --,--""!"--., . . ~ . ... . ' ..

-49 - ---~------------··-----·~~--------------- ·------------ -- ·-·---------·

.. ~ - - .. -- - . - . :- ""': -

· This model has been built for Lehigh University by a pro­

fessional model maker. The total cost is around $80.00, most of the

cost being due to the labor expended.

C. SUPPOR'l'S

1. Model Simply Supported - Four aluminum balls provide

point supports, one at eaci/Corner. /.

' been made in the diaphragm in order

place.

Smal 1 notches have

to keep the balls in

In the s·imply supported case, two supports at one end

provide a free rotation of the structure but prevent any

displacement. The supports at the other end are free to

displace in a horizontal plane. Ball bearings allow

' these supports to behave\as rollers (Fig.~).

2. Model on Middle Colunms - The columns should prevent

any vertical (upward as well as downward)

displacements. At the centerline, 1/8 of

' and hor~ontal

an inch 'way

from the free edge a small hole was drilled in each side

panel. A small brass rod fixed at its ends passes through

the hole and acts as a hil}.ged support (se~ Fig.4)•

The four corner supports are mounted on rollers as mentioned

previously. (

3. Ties - A brass rod (diameter = 1/16 in.) acta as a tie,

which is not supposed to elongate or contract. Holes were

V

Page 58: Study of folded plate structure

i I

i I

I I

I ' ! I

I l

-- - ________..J .. -

. '

' ... _ .. __ ··--~-~~---- -··-. ·~----· ·. ~--- ..... •"'- ~---•L-......___•-•• --~.--,-~.---.. ----,.-•~~-·-•

.. .,.

I

. - 50 -~ -.~ .. ' ,,_;_~ . - :.~· .a.._....:., .. \ •,, ..... \. ~ - . .. .

·-· t . -------·------------------------ ·-----------~-_: ___________ .... __ .. ______ _ -----"-----•-----------

I , - .

"

'

( ) I I

If' .

.

.'

'.

Simple support roller action

~-----+ ----

Fig. 3

·. . . ••

,

Ir washer rod

,,

• •

; POINTS SUPPORTS

-.

·•

Simple support no roller action

1~811 of st ucture

.... t •

,, ·~''\ • I I I . , ' ,.

'

,,,:

_ _..,. ____ .~.:---i" ·_: : ... - - - - - - - - - -- ...... ---...;· .. -~, .---'

COLUMN SUPPORT

-~~-· ,.;:,,,_-_~_-: .. ~,:,...;,, :'--- ~".: .. :'•'-.,;.,;,,,,._•~-·-·· ··-·.~·,.;·:· .. -;---·:•·: .;..'..~j~-... ···~.

t,

..

Page 59: Study of folded plate structure

..• . .... . ,. : ' ....... . ··: -

;,

·., ~( ..

l

..

,,. . ................. ,,,,..,, ....... ' " .. .. ·, .... . . . ..... . ••.,, .,

made at the top of the edge panels. The ties are passed

through these holes and four nuts, one on each side of

each wall, prevent any relative motion of these panels

(Fig. 5) •

Fig. 5 : TYPICAL TIE

:.~ .

•'9•

...

I ,, ,.,..

.... ., ,:;.. :,:

,~ ... . . =..:-..:..:.;.::,x:.~~:....._..;:;..._ .... _:... __ _:~.--· ._......--- -~-v'.'=-.:.~::--:--.::--~ ... -- -··- ~::-:r= - -C'.'%'l!· .• -"· •• .c._-.n;J.'.::.::.....:.,:r..,:.i:.~=C-::0~ .... ~....:,~=:::..'C.: _.;.J.....;...s... c..;.: -:--..• ;,,..~ ::;.~~.::... .. ---~~i;i;.: ;:.:::.-;:c:..?o - .:..;-·.:..r-~Jo;:;-_r:~~.u.~.:,-:,.-~_.;:: • .;~~-::~~-~~ -~ .... ·.1-···•.,..:.,.~ ..... - ... >J_:.,,. . ,··?-..

,_....~·

• .. ' - -.-, .... u,,1.·,,,." • 'I:-.'

·It/,

-51 '· .1... ..

···-. ., ..... ,._,_ .... ·-····~-"' ..

...... . '-'

Page 60: Study of folded plate structure

l I

~ . -

.... .• ~ L .... • .......... I,... -~.-,.. .•.W ... .... ~ ....... ""

t

·\.

--- ----- --- - - - ·---·-···--

5. T E S T S O N T H E M O D E L

A. PRELIMINARY TESTS

E. Zanoni(l) ran. a few tests in 1962 in order to establish the

physical properties of the plexiglas and to verify that the SR-4 gages

were behaving satisfactorily.

1. Test of a tensile coupon for determining

the Modulus of Elasticity of the plexiglas,

. the Po'isson 's ratio, and the creep.

2.. Test of an I shaped beam in flexure for

determining the Modulus of Elasticity

and the creep.

3. Test of the I beam as a column for

determining the Modulus of Elasticity

and the creep.

These tests have showed an excellent behavior of the strain \._.._..-,

gages. The Modulus of Elasticity was in the range between 450,000 and

" 480,000 psi; the Poisson's ratio around 0.37.

From ~11 these tests only the test on the tensile coupon was

repeated in order to check the value of the Modulus of Elasticity. ,In

one year it had increased to 500,000 psi. This value will be used for

the computation of the stresses. (See rr go t• lot).

-- ~s2 . 'J.~ •. ,. !'

..

Page 61: Study of folded plate structure

. ~ ....

------~~, ·- ~ .. ---·---~ . ' . - ' ...,.._, .... ...,.,...._. ' -lf!'l'UI,---:-.... ,_...__._,,._. __ ·--··,,_,. __ ,.__.. _ .... ~~ , _. _- ~"': ,i •:, ;~}; ~ • ...- 'S ·• I,. -:1. . .·· ,,. "'- 1 .- • .

..

.• w.. ~ ...

'···. -53 . .. ' .... . ... . . .. ,...... . " ......

The rate of creep had not changed. The variation of elongation .

of the plexiglas under load varied in function of time as an exponential.

The amount of creep was very small after 3 or 4 minutes. (For safety,

an interval of 10 minutes between application of load and reading of the

SR-4 gage.)

B. ACTUAL ,TES !§(oF THE LOADED !l>DEL .,

The joint stresses were measured at the centerline points and at

the quarter-line points of the model for the different cases of loads,

supports, and ties which have been theoretically investigated.

1. Loading System - A uniformly distributed line load

is needed for each case. This is obtained by using

what Scordelis ( 7) calls a "loading tree" (Fig. 6 ) •

·~. " .

In this _case the system divides one single load,

applied at ,the centerline, into 16 e}ual loads equally

spaced along the length of the model. Considering

the stiffeners of each plate, this is a sufficient

approximation of a true uniformly distributed load.

The tree is attached to fhe structure by means of

nylon loops passed into holes drilled in the plexiglas I

and retained by aknot (see Fig. 7) .,- The nylon line can

resist a tensile force of 20 lbs. In the three cases

. of-loading the holes have been drilled vertically in the

model.

2. Magnitude of t~e Loads - Readings are taken for three

values of the single load applied at the centerline and

·-

Page 62: Study of folded plate structure

l l 1 ~ ;;._ I(

i }.

~ ; i: 'l

l

-'

.\

I I

I I

\ . Fig. 6 ·: THE "LOADING TREE"

'··

longitudinal cross-section of :s-t-ruc:t·ur:e '· !

. " ;· (

' ' {

r. I

equivalent uri.i.forni line··-load: t. p = ·p1:·36 I

I r I

l. .I-- I 1 ' ~ I I .. ~ I I·

:• ~ : . -·~"' ~"' '~ ~ ~ ~ ~ ~ ~ ~ ~" r--,.. ""' "r-,.... ~ I'--.. "" I"'-. "' I"-. "'-... I'-... ................... r---.. ~ .........

r-.. "'-... "' ~ ~"" ~ ........ i' ....

;V· . 'I> '-J ~ Kl k, ..

~ 1....-- ~ 1..-, V '· -.v ... . .

V V. '

V : . . . .. . - . ' . . -

•'

. . . . . f: l' -.. . .. '· 1 :/ :

: ·- .. . . . - -· . ' . . . . - . v .- -. . . . -· . . .-..

V - . :...

v - ..

- . --· ... .. V .... -- -/ . - ... - .

.... . " . · ... · . ·-' .

. . ~ .. . . .. - - ..

. .

··-·

" - ....... -. . . . . . . .. .. . ....

I I

,

r--.J (..... ~ j[..... f..J [.....

.. ..... ... ·1 .1 : '

.. . - -

-~ . . . .. . .. . . - . - -

... • ;

. . . .

;

' .. - . . . -

"

. . . - .. -· .., ..

..

p ·~: T-ota.l. LO'a·d

... ~

hi v V

/

./

/

L,,"

I/

L,,"

V

·~ - - . .. . . --· .. • -·-·

"

r l

\ /: I !,• ,·.

[.

I I I

!: '· i ;·

! : \

I I I

I I

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,.

r I

• ' '

.

-· } .

" 1 '

I > ,

!

I ·,u, +:"'

.,

Page 63: Study of folded plate structure

~ ~.._. ... --, ' . ' '

. -- ' -- . --- . -··-- .. • • • ·. ' .. 'I

-55 ' ...•.

.. - ' .....

.~- ~--··· -- . --- --------·-·- ~ ' .. ' ··-~-----:-----·-·r-•----·.-----~• ··- --·-·· •. ·.,._·-· •• .:...,. --------._.. . .,:.,.'-:. .. _..: ,...:..:..:...:.:. ...

,\

-.

-·- ...----- -- -·~ -, ·"-' -~ ,

Loadings :

(3) (2) (1)

Location of loops,in lines along the structure

.. ~. '.

' ' . ' :

_,

.,.

knot Fig. 7 : ATTACHMENT OF

·tHE LOADING TREE

I ·.·· .I

nylon line ( 20 lbs. test)

- ·- .. _:. ··-

..... ,. . "..j,:......;.· -· • ' - ·=- C=:.;,.::...:..~e.:..: 7· .... . -- ·- ···,;"J;,--,- ....... --,r- ·- ---..:-~~-.. -:e---·. - ·- -·-··--·-=-..:-:·~-f ..,,e,. ".

Page 64: Study of folded plate structure

,C •• I '• •.,,

---- - .. ~---------·· ---- -

)

"

.. ',';•

... - --~-. -. -;·-~ -:-·-:-'" -~··· ·. -·. •' -. - ·-- - r- - - - --· - --."'- - -- - ~---- . -· -.-··"' - - --· ---~ :-- . tJ .. ~.: - ; - - -- ...... - - - - ·--- ----------·

distributed by the "treet': \

O, 20, and 40 lbs. The

computations -of the strains are made for the uniform

load

3.

_P _ 20 100 L - 36 = 180 lb.fin.

Locations of the SR-4 Gages ~Fig.1)

I I I

8~

' II

Io f I

-~-

The two sections are identical and so are the strain \_ .. fl

ga-ge locations. There are 2 gages at each point in order to

check the bending of the plates.

.;.

Locations 1 to 10 refer to the centerline, locations 11 :·to

to 20 to the q~rter-line. All together there are 40 SR-4

gages.

4. Reading of the Strain Gages - The material of the model

(plexiglas) poses a few problems relative to the readings ···, ..

of the SR-4 gages.

(a) Plexiglas creeps.

(b) A temperature compensating gage must be

provided.

(c) Plexiglas is a poor heat conductor. As a

result ~the heat input, due to the warming up

:~,

J4. • ,• • "' 0 •M ...... 0 -·-·~· ~- -. oO •• ... -.-~... :- ,, • ~

l .,p

-56

. . =:-·.:r==,,:" .. ""-'~c;_,.=_.-_._. z-.c..,-_·.-=nt-:cs=_;_-;,..-.-.•,c;.·"-";:;oco~..::-,., ::·~'--'-',, .c,sc-1'__.:..;~, .. , ~,·.·:=. c=-:.c.o;ce.:_;~~-ccc-.;c.:•,w·c.. ··,>·f.• · ,., .•~, .....,., =~":!\ ,.,:,-,~·• ·.,,r=-,;-;-·.,·.T"<'.""' '"'""~'''·=·c:1,.:-~-:--;_-:,~ .. :-.==.-a..:.,_ c...:.. :,;,.,• ·.;:;.,,....=.t..'"='' ="'1•·-'· "°''....fi;.;·n',c Cl~•l "-*·-<o..,., ... ~, :.,·.w.·.a,.=c--,..._:;r;:,===::....-r.-• .i~~ ,.:. ···- :.., '''·';'

"

-

Page 65: Study of folded plate structure

·-- -· --- --·------~. ·-··~. - '.-.· .. - .. - ... ·,··,- - ... · •,· . - _, ___ . ___ .' ___ ._:.·~ ...•• :· ••.• -- ·._·_·,4 .. ··_-· .. ·-. ·-•. · .. ·- -··~·+.--_-· '. -_ .... ·- --··- .:------· ·--. -~---. - .---~--:-.·- .. · ... -· -~:. --. ·-.. ·---:-------. --:. -:--~-~-~ ... -----

"I'

.··

of the gage itself, is not immediately

dissipa,ted as is ~he case for, ~etals,

but contributes to an additional deformation

of the model and of course modifies the

readings. This ''heat illput effect" is

shown in evidence by the fact that when a

gage is modified by the loading, after the

creep has occurred (10 minutes) the indicator

does not remain at a fixed position, but

varies slightly with time, always showing a

positive .. increment (elongation) whether the

gage is under tension or compres~ion. This

last point indicates clearly that this

elongation cannot be attributed to creep.

Obviously this phenomenon is valid for the

temperature compensating gages. -~·

C. THE ADOPTED SOLUTION

1. Instrumentation -

(a) A strain gage indicator, l:S _us·:~d .. ~

(b) A clock is needed.

(c) The 'measuring gage" plugs are connected to

a shift-box relayed to the 40 gages of the

model.

(d) . The "compensating gage" plugs are connected to

another shift-box relayed to 2 identical

'

./

' '

-57

- --· ._:::.-:::::::'7:"...:.. 1·.:.~-,-- ~rr---;;- ~,. . ,r.'Tl~~~';"7, -~r-·..:....-:;r,:L-..,.~ ... ,lr __ .::-~":""..;...-:-r .1.·:_ ·.-:::.;..·1 ... 'L;-:::t.--.·::rr-:::l'.~..::-..r·: -_•:-:-r-:---:_~ ,. • ::..C-:r---r.:.:"':~~1...:.."::"~-.: -::.::.- -:..:.:..'"':.r-=:+=,."::: ·;..·_-::.::::.:·~ :_--:==-=;-::. -·.:.:...·:1:-:-l"::""'-.:.:r::"C--.:i1~~- ~-- _1•-,"'!:.--=;~. ·-.~..::'!'...'."!/t:..:~'lf'"..::"'"~--=.1.1...:::."!..-.r-.;..,......-:--::··~..:--..-.-:..:.t..;.c.--;,~r..J;..-.:•,;:,..::. .: ... :~ . .1:.:.-:....1:.1 .. ~ ·.:...-:--_;.:~--":!::...:~t<.::..:..i.;-,.:.~;;.-'.:.:::.::_...;:;:::_.W,'z_:-:. .. ~~u..'.:x--~ ... tt...~.i~r.l..:...._=-.-~~,.::-_:-__:_::,;,.::::..:.:_ __ _ --:::. .. ;.

---···' _.,.' (•

. I

Page 66: Study of folded plate structure

.. -,. :,:·:'

Ii J I A-f:il1 L•L• -., • •••• ;;;.: 8 w•:s• r•••- :: :,; -.!rrZ!i=!:::::;: tl MWt•:tlJAP ,Q l;

-:-.M .... 1----- -- - -·- -- -~ - --- - M __ .._ - --·~ -- --· • • -- • ••-.:- -

it compensating gages (I) and (2).

2 • Procedure - ( Fag . 8 )

(a) After applying the load, allow 10 minutes for

the creep.

'(b) The box Bl is switched on measuring gage 1,

the box B2, on compensating gage 1.

(c) Balance the indicator. Keep it in balance

f,' for 30 seconds .

( d) At "30 seconds " switch Bl to 2 and B2 to 2.

(e) Record reading of gage 1 (The indicator has·

not been changed).

(f) Balance indicator for gage 2.

(g) At 30 se·conds switch Bl to 3 and :82 to 1 ... • e t-:c. •·• ~­

In this manner each gage is warmed up for·· 30

seconds and tafttn off afterwards. The heat input is the f

same for the measuring gages and the compensating gages.

Th~- ab,lute reading contains the effec.t of heat, but

this is cancelled when the difference of reading is

calculated. (It is as·sumed that 30 seconds is enough

for the cooling of the compensating gages.)

Under these conditions, one full ·test for a defined

, loading and given boundary conditions will Dequire 30

minutes; 10 minutes for creep, 20.minutes for reading

and recording the 40 gages .

: ' .

t

-58 ', I . . . 1

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.·,~·

·- -,, ,=,:o;:.:,,,.=.,=..-=c:-.-c.·=-··c-c-,-;:·-~.~:·=1!-.... ·=·-:.,=:•. ·: ... ;· . .-:f~ .. ,, ......... ~ .,.. ..-,,··=-s·,.-.. ' '-::---.-~. . .. "'" •c-,,,,·,;;,· .. , ,.-.-. "'· :;.:.-:,,:~;.;~:~.,"'"''· ,:-::,:...==="'·'' .::c"::'.C.:::r-==c . .:!!..._",·""·""":, .. ~t:, .. :;::i...e-::r ="-:.:-..;;.\C.'.::. ,. u.,,:C .. c·,:c.: .... c....-::,: ~:·.,·,=~~-'--~-=,=~,==--"·':f-'-'-" ·=-'-·""·-·="'"-"'-c-'c.,:,:;c.=·"'..:==-~-;.:-~=· =--=· .. .- -==-..:..,c..., .. : . ; . ·r· .

I l ,)

Page 67: Study of folded plate structure

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' . • <.•f .-·, •• • II•• ' ,, .Jt. I ' • ,.r•_, .. _,1o1t,9\,"', I ,.. • ..... ··' ~ '~

1 •,.•~J._·;, •• • •' . ~ ., . (. , . •· --------....,,.......~-----~- ~--·-----"- -· ··-- ·-·-----~-·~

-

··);:(g-~ 8 i STRAIN READING EgUIPMENT

to the 40 AS SR-4 gages of the model

l

j, ••

1 2

r

· ..• :

switch box' B2

A5 SR-4 compensating gages

switch box Bl

measuring gage

compensating gage

clbck

strain indicator

. . ~ ·- ·.;._' •• · . .: .. :~---.-~-.·.~~_:, _ _:._:_ •• _ ....... :.....u.1-~ .... ~~-• .I.~ll,_J!_,.;,."-·o.L.·.,_;,_____...L,.~~_.::.,;.' ' .. ::: ..... : _:.J';:':-= .• ··<" -r:-:~.:-.~:=-'"'.-.,::r:-._;,,_.._ ~..._._...,..,:t-.!C..! ... :::._.'!.....;.\-~--- ,_:_.------'--=-~'~.'..!l, •.• •. ·-~.,r-r:.:,~ ,~1~·~11.':~L!l.'..t.L C:_.'., . ._ .. -J1,,~·-.. ~ :.t.>--G. ~~~ ~"::!!J:.:. .-~tn-~~1'1:Y.11.,<lu.r~ •• \'. ·~J • .;J,-"\..'-"'•'e'IU.J;:l.." .. T"l'Jo!~J.:;;:a:Li...'1,',;"l'l,;;.:'_.-.:; ...... ~ .... ,.u::r.~·.,·_:in;c":-.':.11.)..' ~-.~~J.r:.1d.:'L.l!:l.:...."l.,J/1-----=.. ;c:.a.:.,,~~-- ... '\:C'"..t.....:_~ .. .J.'.., . .:!.\.l ;,;.::..::.:ll.'.lt...x.r··.:r..:::::..·:-:-_-;-, ..:...·:_-~·____..r;:_ ;_ : ... -:. .:._::. ... _;;.i:... ~..:!"!" 111_'!:..,,-·.:.·.· -~\ L~,•-... •.;.: --.. ...._

. • ....... ,,.,. ·-·-,, ..... ·•, ··,·: ··., ~ ,,.:.,-,, •;.,.-.t>·- -., ••. ,., ·,· -,_•'"•"1: .-;;,.•·, •. ,•, :.,r.,•, ., , .•. ,.,

I -

Page 68: Study of folded plate structure

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)/

"/·'

I

. ' . . -· ' . ·. . '. . ' ' ' ·- .. :··:~:""--:.~· .. :"~·:···-.•·· ~-"' -. .

·,. -:r:•

· · 4 t ·"

l

A

.. ,. /'

,..._

I ~ .u

-

u

Twelve different cases. The average results of these tests.·

for Cl and 1/4 points are recorded pps. 77 to 88.

\ D. S!RA:INS AT RIDGES, FROM THE STRAINS AT SR-4 LOCATIONS

I

A linear variation across the width of each plate has been

assumed (assumption No. 6, p. :>)

5

-~ .. -- .. ;.

*4 5R4

b -

.._ ..... o.s

I C l C. -

-60

Page 69: Study of folded plate structure

.. . , .. ., . ' ·•··. •·,'

- -·' ~ -··· .

---· ----. ··- -·- -- - ----... - ·. --··,·- . ~- -· - ... ~~ --- . ------- ·--'. .. --··-- -----... ---·· --

B ' B --

Let us consider the plates 3 and 5: . ,..

a' b' b" c 1 are known.

A" B' B" C' must be determined.

From figure on pag_e 60 .

+ B" 2

b" - Cf

4

a" - b'

a.nd

a" - b' = 5 - 0.5 - 0.5

-------=slope of the strain line 4

·A" = a" +

B' :·;:: :.b·' +

B." - b": + -

c• f - c + ...

a" - b" 4

b • - a" 4

.b·'' C ' 4

C ' - b" 4

(+ 0:~ 5).·

(+ 0:.:5):

..

( 0 , •. 5.)

.( 0 •. 5:)

These joint strains and the corresponding joint stresses have

been computed; they are tabulated (pp. 89 to 100).

-61·

.. ;_.

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Page 70: Study of folded plate structure

l ·

-62 .. .. .. ... . '· .... ~ .... _.,~ ~·· '..... "" "' 1; . ••• • .6'

, .. -. --- ........... _,,,. _______ _ ' • I - - • - - •-- - ,.,. • -· - • • '• • . ., ..... ; . ---- - ---------- - --- ---- --~=&.---- .., _ __:_ ~--;-·-·---- ---- --· ... _____ ,:__ _______ --- -~ - -- -- ----- ·- ------- --------- ------ --~ - . ·- -- ----·-·- - . -- - -·· --· --

6. D I S C U S S I O N O F T H E R E S -U L T S

AND CONCLUSIONS

A. DISCUSSION

1. Preliminary Tes ts

The determination of the Modulus of Elasticity, using a small 1/\

'

tensile coupon, might not be quite accurate. E. Zanoni suggested that

b:"~fore building the model, the Modulus of Elasticity should be defined

for each plate. Each plate would have a length of 56 in. (instead

of 36 in.) and would be used itself as a tensile coupon. Afterwards

it. would be cut at the exact length. If the values of E vary from

one plate to another, these different values would be used for con­

verting the strains into stresses .. This would give more accurate

values.

Yet this would not take into account the effect of the joints

since the gluing might affect the value of the Modulus of Elasticity .

.....

,---'--:

Page 71: Study of folded plate structure

,,,. ... ' .... , ~. . . . ' .. ,',. } '.!"''··· ..... ,..,

·J

2'. Comparison of ,the Experimental and Theoretical Stresses

(See Tables on pp. 89 to 100)

\

(a) Model simply supported

ct points

1/4 point.a

(b) Mode·t,. on mi;.ddl.e,. colunms

ct polnt~=

-l/4 ,pp:i.:nts·.,

(c) Model simply supported with ties

CL points

·t/4 'po . .±nts'.

(d) Model on middle columns with ties

(i points

1/4 _po-int~

Loading~(!)

excellent correlation

excellent correlation

good correlation at ridge 4 and: ·6

Load!ng (2)

good correlation

good ·correlation

go:od correlation

good good correlation correlation at ridge 4 and 6: at ridge 4 and 6

no correlation even signs are different

no correlation

no correlation

-

p·oor correlation signs respected

poor correlation

poor correlation

poor correlation

Loading (3)

good correlation

good correlation

good correlation at r-idge 4 and 6.

good correlation at ridge·4 and .6

satisfactory correlation

similar variation of stresses

satisfactory correlation

satisfa~tory correlation

-63

'" '

Page 72: Study of folded plate structure

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. .,,. . .,, . •. "' . ··.:- , .... "'"' . .. ,,.. .. , ·.. '\ ,.. . :·.· .. ·- .... ~ ... .,. .. _. , . .-~ ......... ~ .....

.... . . . .. ' '•·

' .

..,. " -- . .. .. ... ~ . ..... ,, .. -•-•'if ..... ~..-~-··.'.~.·:···~--~~- ····',"'!""••• ' ". ,..... : ''." ... , '·~ .. ..

B. CONCLUSIONS

1. The results are quite satisfactory as long as uniformly distributed

loads are appli~d to the structur~.

In these cases the experimental stresses are very close to the

stresses computed theoretically.

2. The results at the quarter points are good.

This would indicate that the effect of the diaphragm is not

e·o .be considered at these points.

3. However, in the cases of concentrated loads the theory does not

seem to be valid.

The distribution of the stresses has to be investigated for ....

these cases. The moments in the plates are likely not as they are

considered in the present form of the theory. A knowledge of the )

actual plate deflections would be appreciable in order to modify

the analysis. ...

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·-~ ·.

·1

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Page 73: Study of folded plate structure

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C<r,,_,..._,;.,. • • . . .'"··' . ,• ... • I •.· ' "'• •

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,t ...... , .... -~ ........... ' ....... ---------- --- --·- - .. - - -- - ------- --·- ... ·---- ---· -- - -:-- - .. -- ... -

- --· ·-- _.. - ·- ... --- --·-- ·- ·-· ·,­,·. - -------·-,·--- _;_;._ - ....... ~ ... ! ___ .;::. ::: ••. -:~.: .. ,:... ~:_; '.:- . .,.

I ' ,'

3. Possible Causes of Errors

Unsatisfactory results in the case of ''model on ·middle

supports" might be explained by the fact that the beams (steel 1 in.

x 1 in.) supporting the model under each of its free edges are not

·sufficiently rigid relatively· to the rigidity of the model. If this

is the case, a certain amount of deflection is allowed at the middle

supports. The theory assumes zero deflections at these points. Since·,

the model does not behave as a be·aD.J, -t;·lle i.rtvestigation of the effects

of partial deflection:s on the joint s,t:re:ss:es is rather involved and

will not be made here. However, before proceeding to further testing,

"thJs .investigation should be ma.de. Stiffer beams should eventually

b·e used.

In a general manner, the. s:trains obtat.rted :in ·t.,hes e tests

-~re of small magnitude, usuall}r less than 100 micro ''/". The accuracy

+ . of the reading is of the or.der o._f - 5 micro ''/''. When the strains y ·-

are below 20 rnic.ro '-•/:''.,- thi.s gives a high percentage of inexact! tude.

In the: f1Jture, higher loads should be applied. The total load

·here was 40 lb_s -., A load of 80 1 bs . ·c.~uJd. be used without danger to

the model.

-·~ . ,

. .....

:·•.

--c:,.:_-,·· ----•·-----.... ,~-,_,.,_·;·..:=.-,.:-c,.J'--"::,-".:._i'-=-->..:.-"'...-=---c...._=-...==..,.,~'--'-'•...___"--===•,--, -·,c-a.r-ad!:.a.:::'.....,.:.:""-=.:::..e-~-:-='"'.:._;~-__,,,.---=-=j;:---,:::,~-;:,_•=~--".•~L~°":4a.;.C:..:""-'-;t:U.a."~...:;.:"=·=-""'----t='~~~· __::·'--f\.:_ ... ·~w'-·.,~_-.:..,.;;::,_~~-~.·~_ ....... :JUA.:21..:.i.01·-~~-lo~~ ....... lt.U;p.,,.~>1"11~~~U~~-.-;.·,·._1.·.:; ..• - ". = ,,

Page 74: Study of folded plate structure

• • •.. .· ,<.

. -

....

-66 . . .. (I. • .· ' ,,..-:&;' • . '. ,, ...

••• •••• '·' ..................... ,. ... ......,_ ... ..£ .. ·'4\i.' ...... -, •..• r'.4i:•,.i • ,"4~•· ............ , •• i ,.- 1•.-,1 ~ • >'•'••••••,• •. • •' ',·~" • I •

---------·---

.,

7. S U G G E S T I O N S F O R F U R T H E R T E S T I N G

A. EFFECT OF DIAPHRAGMS

I The assumptions at the base of this theoretical behavior of a

folded plate structure neglects the effect of the diagrams. A diagram

is considered as a simple support which does not induce any restraint.

M:>st likely this is not true. When the structure is· .loaded, the

diaphragm deforms ind:u~t·ng res train ts .

B. PROPOSED TES1~-

· Place ·strain :ga·ges a,roltt)d: ·the edges of the diaphragm (foil

g_a:g_·'=!-~ would: gl:ve .mos-t acc:.u·rate results because ·of their small si.ze.) ..

·p1ace closely spaced fo-1.1. ga:·g¢:$·· to.w:~rds ·the encl$.· Pit. t.:he

·P.a.ne·ls .•

.. :Load the structure and take readtlJ.gs. Towards the ends the

:cfe:fo.rmat:ion, if the diaphragms have no e'ffect, should be negl-igible. ·

If the readings are not· zeros, place a stiffer diaphragm

(by gluing). Load the structure and take the readings.

(

By repeating this procedure it would 'b\ possible to determine

the effect of the diaphragms on the stresses at the ends of the

structure and eventually to modify the assumptions, regarding the ~

diaphragms in consequence.

i

.I

Page 75: Study of folded plate structure

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.~ ' ..

,,.

. .. •., ...... ............. , .. . .. ,... • Y'I'• ~ ,. " ',. .... •• .• •• • ...-• ..... "I' • • '"' , ••

.( .. ,_ -

C. STRESSES DUE 'ID A DIFFERENTIAL SETTLEMENT OF THE SUPPORTS

., The model could be either simply supported or reposing on

intermediate columns.

The difference in settlement co.ul.d be provided by usi.n_~:.

screws at the supports, which could ·b~ ,c:idJ.usted at different tevels· ..

D. MEASURE OF DEFLECTIONS

It is assumed that a plate deflects only in its· plane:-., ·Fo:r

the, external panels, which are free edges, this is obvious.ly· not: t-ru-'e \

:and it is mos-t li:kely no--t true for the other panels, es'1?¢:·c1.·a1l,y :in

·the c·ase of non;..s:yrtnnettical loading.

A. knowle4·ge of the exact defle.c.t:fot1s, wou·td help in defining

these deformation·s i.n a theoretical w.'a,y· and.: :on .this basis a correction

for stress e_s: could ·be· .proyldecf ..

,• ":

~-

(. }

'

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rl • •. -r

..

Page 76: Study of folded plate structure

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8. APPENDIX

:-,.,..

••

•I ·, .-•

I'

;:_ . .-- : .. ~ ·-.. - ----··-·n·.

·····-·-,l.... - -- -·-

Page 77: Study of folded plate structure

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·C EiiTER LI lJ.E ..IJI.D(f E 3TR~S ES {J"~~r·:L_) t :ODJ~L f3·I l ::J>L:Y :SJTP:P:OlTTED

Loadi.ng· .. Elem:. loadi.ngs. ·c) .4 6 8 lo - 2 3~·9 1 .·4·99 - 2·42

( l) USO US:[ NS

- 4 847 ~ 9 695 - 7 221. SYl-ll·IETRICltL 870 - 856 .421

_. 6 ·376 1_0 ;338 - 7 092 - 7 092 p

:us:1 -· 3 999 7 998 - 5 998 -. 5 998 . (·2)

U:~l ..... 6 267 12 534 -21 877 21 877 ·:trs 615 - 605 2C?8' 2Q8 , . ,;

l'lA. 6 010 - 8 505 12. 4·93 -12 493 ,, . ' .

~ 3611-:1 11 4·22 --15 08.4 3 .68lt-

lJSO .5: ·0°0 - 181 :636 636 . . ') : ..

USI 2: 199 3°9 ·3 299 3 299 . ' ~ . ·- . :,I · ... - -UAO 1.- 774 .. .3 06:9 1 023 1 023 -· -' UAI 4. 3qt-"" ·e3 789 -15 340 15 3ltO ('3) :--· ., )

NS - 264 260 - 128 - 128 liS 338 ~i 161~ 164 -lTA 665 l 382 1 382 ~: -!TA 4· 214 5 ()64 8 760 ... ' 8 760 - ,

6 893: 1 842 .- a 566 4 312 ... , .,

.

10 338 .. 6 376

7 998 -12 534 - 605

8 505

3 361+

- ~ ·1s1 399

~ 069 789 -260

~~f --5 964

448

- ~. 999 6 267

615' - 6 010

- 3 227

5 090 2 199 -

~0 4 774 4 395

- 264 338

-665

4214

- 963

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7= ?90 - 4 774

- l 000 --·~ 998 - 4 4-9$ .~ 4·4qg 5 998 ~ 3 000. ... 4: 700 9 400 -16' 407 :16 407 - 9 400 4 700

·435 - 1~28 211 211 - 428 435 4 250 - 6 014 8 834 ~- '8: 8311~ 6 014 - 4 250

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8 817 - 2 3·86 - 1 649 3 2'?9 - 2

3 580 - 2 302 - 3 206 6 592 -11 /

- 187 184· -239 - 235

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477 474 - 2 767 505 11

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Page 86: Study of folded plate structure

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MODEL SIMPLY SUPPORTED

'.OU.TSIDE GAGES 1 INSIDE GAGES

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1. ,;;. :2.

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75

159

145

40

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140

135

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17.50

- 45 .00

- 63 75 •

- 152. 50

- 148. 75

- 25 .oo ·- 13. 75. '.~ so:·t>.O: . t .. ~ 55 00 ·. . .. - 68 ._·75.

lJ.-~':25

-o .• oo ,- 72.50

- 71.25

27.50

33.75 '

s.·oo· 125 ... ..

·.-. ll .·25 ...... ·

Note : Strains are in micro '' / 11 for a loa·d.-. p·· ,=· 20 lb·s··.

·'·

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. ..

Page 88: Study of folded plate structure

I

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CENTER LINE LOADING

MODEL ON MIDDLE COLUMNS

,..

OUTSIDE GAGES INSIDE GAGES

TEST f/1 TEST /12

l -. 9:5: .. 75· - 40 - 20

.2 · 9.5: :_$.0: ·9.0: ao· 3 its.: :.95: 70 :5:0· 4 ..... '.6$: .. .-65 -· :s.s .... 6.'5 5 - 85 -· ·a~, ~ -8·5. lllllit :6Q.'

:6. - 6'5· - 60: -· 6'5 .-.; ,o,

7 -: .. 50 -: 55, ·- :60 -: 40· .

:S: 75 85 ·6:0 " ·'

:65

9: 70 90 ·70 -ao.: 10 ·- l.-.60 - 165 l.0.0 85

11 ._ ... 45 - 10· ' .: _: ~ ·~:5:. - :)'().

12 :ao.:: 80:: :.65 55

13 :so :6'5. :.7Q: ·:65: ......

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.15. - 70 - :·50 - 50 .--·· ., s·o 16 - 60 -~ 55· - .5:0 -~:. 45.

17' ' .1·:. - 5.d - ·-40 - 3'0:: - :~·o 1.8- :65 6:5 5$: '60

19 1.0: 7.:5: so: :p'.5:

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- 47 50 •

·86·, .• ·~2~

.82:. 50:

-~ .·62' .• ,o: - 78 .. 75

·--~ 6s<.·oo . ' '

=- 51. 25

71 ... z~ 7:7.:5.0

~- lQ, •. 00

- 3 7'. 5()

65 .oo 70 .00

43 75 - •

- 55 .00

- 52 .• 50 " :3_7 50 - . '

'61 • 25

65 .oo 28 • 75

Note : Strains are in micro 11/ 11 fo.:r :a load P = 20 lb:$

.• · ( ; ·. ~

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Page 89: Study of folded plate structure

.;;. ·, /. . • •• _!_, • . •·•·••• . •.• .... . .... ' ,. .. .,, .... ,

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- RIDGE /JJ. LINE LOADING

MODEL ON MIDDLE COLUMNS

OUTSIDE GAGES · INSIDE GAGES

TEST 111 TEST /12 TEST /fol

- 105 - ioo ·a:s:· 1:25: ..

65 65 . .. - -- .· 70 ·75:

'7():· :55 4;5:. .40:

·- ·1.40 - 140. ~ .. 125 __ , ·13·()

;~. ··145 - t40 - 1.20 - J.:30: :1.5·

..

5 15 .. 20· ..

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-· : :s:o: ·- 60 35 5 , 3Jl 4Q: -· 40 -· 35

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65 50 :50 .,,5

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- 95 - 95 - 95 :-· 1.o.:5 - ,.._

10 25 :20: 15

25 :35 25:· 25:

15 :35 lp' 25:

:l.5 ··zs 25:: ::3.s

- :25 -· ·20 ~.: 10 ·- 10··

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·--~ 1 • 25

:-6:3 • 75:

5:·2·.5,0

·- 143 75 •

;·-- 1·43 7.:5 •

13: .. 75

43. 75

22 .• '50 .. 2-J' .. '75 ,.. .. .. .

- -25 00 •

·-· 1:. ·25:

75 • 00

55 • 00

~- 96 • 25

- 9 7 50 •

1''7 • 5-Cl

z1·. s:o·:

22 • 50.

·25 •:00

- 16 25 ••

Note : Strains are in micro "/" f:ot a lb·ad p·· = 20 lbs

-81

f

.. .

Page 90: Study of folded plate structure

·--•~••·-c••---~-~~-----------------------~------,---,--~e,-.,,--~-,-----,.·

-82 "_ ...... ,--~·:--· -,~·-;::...I __ ·"'~-.:~---,.-:~:~;~:.:··-~~~-.. --~-~--.. ~ "':.:.r_ .. ~::: .. ·:-~-.---,..~:-::, ··rr:w:.:_-:"~.··.r~--~~~: .. ·:~~--·::· ..... --- --~.:~· ·-·-··:·-·· ~-:··"-_- .. - ... _.._ ...... _.,. ~--r .. -~ •,•o<l•", ... :.a~ --~--~ ... ; 't•" • • -· ........... ~ ... - ~-,, ... _..\,,,- --~ -~·-- .. ~- .. •• '·.· .. ·• "', , .. ~d··.-~~-- .. ~·~1_:/".:~.-l.-~ .. ~~·-,_· ... ·1".-~.'~, .... ~l;,: ..... ;"_"·-~· ··'· .. u:,.:-:..::~1--. '""'-::1··::-~·-· '°' ~~::'-~~t:_-~-~-.!~

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MODEL ON MIDDLE COLUMNS ·

OUTSIDE GAGES INSIDE GA~ES

GAGE 1J TEST 1/1. TEST 112- TEST /fol AVGE STRAIN

1 .20: a:s.: 75 6s: 61 • 25 ·2 5:: . 10. ·2.0 :10 11 •. -2.5. .- ,•

10' -3 -~ lS 10 10 ~: ·6.:25 1-·

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'

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t 15· t 2· ·10 0: 10 8 :75: '.? • ~ ~

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!1 14· -~- - - - 95 -· 5.0 ,,

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i •

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Note : Strains are 'in micro "lu for a load P = 20 lbs · ... •,

·-·

Page 91: Study of folded plate structure

'· ~ ,.

CENTER LINE LOADING .,

. -MODEL SIMPLY SUPPORTED ( WITH TIES )

OUTSIDE GAGES INSIDE GAGES

TEST 111 TEST /fol AVGE STRAIN .-~.. .,,t

l ,45· :40, .. 45: 40 43. 75 .. . ,

:2 ·- 10·. :4:5. 15 10 12.50 3· ·o: - :10 :5 - 5 - 2.50 ..

4: ~- 40 5,· - 15 - lO - 15 .oo 5 - 30 ~ 20' - 30 ·- :3_Q - 27 50 .. • ·9· - 35 - 10' - 30 - 15: ~: 22. 50 7 - 30 - '20' ·- :3Q ·- 20· - 25 .00 8. - 5 l'O ·o: 10: .3:. 75 9· 0 15 0 ' .10. ~. 25

10: i:3.,5" ,:S:'O .45 .55 46. 25

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Page 92: Study of folded plate structure

.... ,..

I

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·,;. MODEL SIMPLY SUPPORTED ( WITH TIES) . .,_.

GAGE 1/

1

2

,J:

4

.5.:

·6:

··t ·a·

9

:10

1·1

12

13

14

15

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17

18

19

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. =:OUTSIDE .. GAGES

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70

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60

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105

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45:

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100

95

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15

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20

20:

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45

40

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--

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-

58 • 75

30 .oo 11 • 25

101. 25

97 .50

51 • 25:

S-·6: .. ·25 . ...........

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Page 93: Study of folded plate structure

-85 . .

.,.. ... ... ... - . '". ___ .,.., .. ,. . ................ -··_, ___ _..~, ....... ,.,.,.,:._.....,-- .. ,....,.,- ....... _,:~~I! • ___ ,_ .... , .... ~ .. __..t....;----• -· ................... '" .• - .• - 'I.,.. .- " I---•• ~ .,-\ ...... ··- ... • • .. • .. • _,. ... ... ' .... - .. -- • • • ~,-,.. • ..,· - --r,.:.:...:.~~.,-.. .... ,"\.,.~-u.L.-'-~..: ·- . ·-~~~ .•~-~,,_:. -~~---..:.~~"--'' -~ :. :, ___ ' -I

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l

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6

7

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13

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17 18

19

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CENTER LINE PLATE fi3 LINE LOADING

MODEL SIMPLY SUPPORTED ( WITH TIES)

OUTSI.DE. GAGES INSIDE GAGES ·,,

TEST }fa.:2 TEST 111 .TES.T .. /p2: , . AVGE STRAIN

,115

:0

0.

~. '85:

-. 5:5..

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-

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10

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- 70

- 75

--

75

60 :~o: 10:

:2.0:

10,5

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5

55

60

so 50

20

0

10

90·:

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.55

65 15

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- 85

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·.- 70

~ 65 ..

:45

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Si.5:

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0:

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20.:

5.

..

107 .50

16·25 ...•. ·- :2· .... ~:o· - 1.o·::.00:

.... 6().00·

52 .... 50 .... :.62.5.0

' .•.. :22 •. $0

·13 .. 75 . . . .. .

6_'3 .=:·75' . ... , .

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- 66. 25

- 62.50

25~0(l

3·3:.,]5::

z ... so: =- 2.5.Q.:

11. ·2s·. ....•. ' . .

Note : Strains are in micro "/ 11 fot·· ij: lg.ad. P = 20 lbs

••

i'

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Page 94: Study of folded plate structure

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1.

2

3.

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:8

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1._2_.

13--14: ·1:5:

16

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.,,.-,. ··.-· ·- .. ,, ' • ••-•· ••• • I ! .........

CENTER LINE LOADING

MODEL ON MIDDLE COLUMNS ( WITH TIES ):

OUTSIDE GAGES

TEST /fol

10

2:5'

5

- 15

- 20

- 15

- 20

15:

2·~:.

·s· .. ..

.10:

0::

- 15

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TEST /12

10 / I ••

0

10

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10

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10

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20

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AV~ STRAIN

- 10.00

7.50

1.25

• 18.75

- 17.50

- 16.25

-. 16.25

12.50

10.00

15.00

16.25

12.50

5.00

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11.50

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l

Page 95: Study of folded plate structure

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RIDGE 1F~ LINE LOADING

MODEL ON MIDDLE COLUMNS ( WITH TIES )

OUTSIDE GAGES

TEST #1

100

10

20

- :120

-- :110 I-, .. • •

~-·

---·

-

5:5

:'5''.$

._·5_'

10:

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5:<l ::ZO.

70:

75:,

65

55:

5

20

5

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TEST _.1!2

95.

:.5:5

:20

-· :75

- _90

7.0

:as

- 10

- .30

,35

.. 4_.5:

.:45:

20·

- 80:

- 75.

:60:

65:

:- ts.·

-· 10

- 10

-

INSIDE GAGES

TEST 1ft 1 ·'

0

·:25

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- :9':5

-· 10:s:

5:5-

50·

10

- 10

25

is:

,35:

15 . ' '

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25

45. :35

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15-

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40

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... , ..... - .:- ............ -~····;· ....... -....... -. .. .

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AVGE STRAIN

55.00

33.75

20.00

- 97 .so - 97.50

61.25

66.25

- s.oo - 20.00

26.25

30.00

40.00

22.50

- 75.00

- 77.50

56.25

51.25

17.50

- 15.00

17.50

.. ·

Note :· Strains are in micro II/" .for a load P =i.~. 20 lbs

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• 7. > .::._._.. • ::. ••• -·- . ~:-- --:··:-···: ·-. _,. ___ ~ -·- -...

. . .. '

'. --.~ ......... , --.· .. ~ ... -•· .... -- .. ··--···

Page 96: Study of folded plate structure

i !

1

l l ...... -·· '.. ' . ' ~., ................... ,_ , .. -...-••4-.-.•. ·-·· .................... _...,_., .... _,,_ .. ___ ...... .

I . ,

I i j I

:I I I \

... :,·;

,.

'

._.._..___..,.,.. .• , .• _;:, ~,,.;_ • , ,· .. ·.,..'.-, •.• :.·.:.:, ''.., ,I · ,._. .'--• •- . ..,. __ ••• _'.:_,,,_, .• : ·-··~--·:' •. .,;,_',. , .. ,;_'._;: --~·._' • · - s.'.'. .. ·.:. •. " . ,, .•... ·,,,: .;:,···· ; .. ·._ ' .. ....... _ ... __ ~ ...

·····•· -... ,., •... : , .. · .or,'i1•~'" .,.-:.,..,;.~:.~····

... .......... •, 1• ' •. •. •. ,,.., .. ,· •' ,. ·•r • ,• " • ~ .. .,-

. ··---~ .. ··- ~--.... ' . .•. , • ... ...... . .......... u .... .

' .

' .

CENTER LINE PLATE 1F3 LINE LOADING

MODEL ON MIDDLE COLUMNS ( WITH TIES )

OUTSIDE GAGES INSIDE GAGES

:/}2: . GAGE II TEST /fol TES'!' . 1;2 TEST /fol TEST A.VGE . STRAIH

1 so: :So .85. 110 88. 75 2 ·10'. .010: -15. 20 13. 75 ·3: lO - -lO: :o 0 o.oo 4 _, ·so - :90· :- :65 - 70 -- ·73. 75 5 ~ ...

!ie .. 70: 85 70.: 65 72.50 -~ - - -·6· 55: 40 -~,5 40 47.50 '· ·.

7 70.: ·s.o 45 50 53.75 8 ·20· °() :.10 5 B.75 ·9· :s ·- =2-5 ' to: .. 5 - 3. 75

.... . · ..

:10.· ·--· 85 - :1"5 a·s: 90 3.75 '\ -'~

:so: . . .. ll ·BO.: '30 15 :41.25 "~ ..

12· :.30 :ts .3_() 0 23.75 .. 1.3·. 0 - 5, 0: - 5: - 2.50

14· - 55 - 6.0 ~ :45 - 55: - 53. 75 :15 .. 80 ·- 65 ... .S.5· .. 55 - 63. 75 16 35 40 :3:~ 30 35.00 17 35 35 .. •.

;3:S. 40 36.25 18 0 0 5 0 1.25 19 ~ :1.tl 91!"" .io:· 0 .o. ;"9_: s.oo

·10: 5; S·: 1.25 20 5 .....

··-· --

Note t Strains are _in mi_c:ro '''/i", ;

·fo:r a. load P = 20- lbs . . .: ' . . . . . . .

---· . .-..

/

··~ . .

. ----···-~- ------ .,.. __ , .. _..... - - .. ,., '. - . . ' .. . . . ., . . . ,._ - ' ·- •· ~ ... --· ,_ . .,._.. ··~ -~- --·- .. ,,_ -· .. •·' -- ..

II

I

. I !

' ' I . . -· -- ..... _ .. -~\. .... -- ..... -~. -. - . . I l I

Page 97: Study of folded plate structure

.. .,~ .... ~ • < "V, . o, -:.·-•':.•:...,-. , . ...- .. -,. ... -... .. .. .1:.. ••I · • • ~• ·: • · ... ~,a..,., .. "' •

'•' ... ,

-1'"

CENTER

POINTS

QUARTER

POINTS

I •

• :.,,,. ~········ ,,.,,, •.. ·.1 .... ·--. • • - .....

CENTER LINE LOADING

MODEL SIMPLY SUPPORTED

RIDGE 1fo A.YGE STRAIN

0

2:

4

6::

8.

'10·

:o

4:

6

:s

·10 •',

- 57.28

106.25

-- 72.16

··- ·7s .• 13

115. 62

·- 57 .34

- 42.50

87.66

~ 58 .J:8 .....

- ·60.06

93.67

- 40. 78

-..

·.· .....

.• - ' . , . ""-'llo;,-

-

-"' -

-

EXPER. STRESS

28.64

53;13

36.08

37 .57

57.81

28.62

- 21.25

43.83

-·- 29.19

- 30.03

46.84

- 20.39

-

--

-

THEOR. STRESS

.35.42

57. 4_3

39.40

39.40

57.43

35.42

- 2.6 .. 52:

43.28'

- 29.64

- 29.64

43.28

- .26. 52

i--. -89 '

. . .• .. .. .., . .......... ' . ······-., ,· ...... ; ·- ' ~ ·····>.~.1••1·, ... \,\--# ....... _ ........... .....

\

Note : .Str·a,ins .. are in,1' / 0 .,:.s·tresses in psi , for a load P = 20 lbs

- .... .... . ·- -- .- - .. .. ·- ..,.. - -·- ,.

' .. ... _.. '~··· .... .. _._,.. .._., .... ·- ,,... ... ,, '°'-I' , .. •• • ,,, .... - ...... . .............. "" .. '" . .... . .. . ..

.l -·- ·•• •-•• -· ••• n--•• -----------·--" ,., . .,._ ·----•• o- ·• - ~--••' ••,--.,---~-, •• -a..•, .. -., .... -•-~-• -, •• L, • • " :----·--~-.... - ·•••.-----------• , .... •--~·-•--"• •• , •. ,_,_,_.,. __ . ' ·•• ,, '

(

Page 98: Study of folded plate structure

..,,~ '· . . ' ·-•-------- ..__. ___ , • ·-•· (• , , , 1 ,.,_ • ,rr • •· .~ ., ........ .._ ... . ,. ........... .. . . ··-··· ., .

. .. . ':...":,.~ .. , ,.

CENTER

POINTS

i i i I ' I ;

·Qtr.1\RTER

. POINT·$;

RIDGE #'J., LINE LOADING

MODEL SIMPLY SUPPORTED

RIDGE 11 AVGE STRAIN

......

.O' - 29.84

-2: 91.48 .,_

4 - 178. 87

6 .. 24.06

a 26.55

ro - 41.06

o: --~- 16.5,6

:2: 64. 64

4 -- 124.06

.. 6· 26.81

.8 23.28

10 .. _ :2& .• 5,6·.

-

-

~·-·

-

-

-

EXPER. STRESS

14.92

45.74

88.4~

12'~-03

13·.2'.8:

.. . .. ..

20 · .:Q::J: . . ....

8.28

32.32

62.03

13.41

11. 64

..13 • ."ZB-

-

·-

--

-

-.

.'!"9

. ... '

THEOR. STRESS

20.23-.

63.46

83.80

20.47

18 69· . .

.l7 •. 9.3

17 .75 . -. .. . . .

49 • 76

65 • 89

18.26

·12 .• :13

:11 .. _:75 . . ..

Note t Strains are t.n. micro "/ 11 , Stresses in pe_i' ,: for a load ~ = 20 lbs

··.-.·.:

'.., . -.:. ,. ;:; - '': ••. ... a

\

-90 1

•·

.· ....

.. . ...... , ... ,. ._, ____ .,, .. ······ .... • ---~:.··. •• ; ·- I 4• - •• ___ _, -~-- ···-- • '•h' • 0 O O ' ••• ---·--- -· •, •• •·- • ••• .,,_, __ ••.•• \ O •· ...... ;" > • ..... • • ~- ............. -........ •• __ -~--... ,- - .. ' O ~~ .- ..... • ..... - ---····-.. •-..,Jo.,· ... _, ... O •

Page 99: Study of folded plate structure

r-· .

'- -

- - .. -------·- - - -- - .. ----- - ······-·- ---• • - _,,uo ,,.-,--~.-. ·--- ,04 . ..-~,-~--, ••• oO -••,•- ·•- '• ··•,-••, ·.•·•·•---~ ..... -,:·-~~M-- •-•• • -· .- ... ~··,_:~-·.: ,..~ .. ,,.~.--~,:.~' .. :.;;,~;.;.:_;:;.,:;.:;.~.::.;;:.:•,~'• ,. ,•,: 0•,,,.~,\-' -•,,.., •oo ••• .. w. 1., ............. ~ ......... _. '. --····· . . ,,., -- .. _ --

- •• 1- ••• ·----··---.A•.·'• .... . .. , .. , ....... •· _,,. ... ~ ....... ,.. .

)

,,,... ..........

CENTER

POINTS

Q.UARTER'.

POI.NTS··

--.,-, •.. • .H

....... _ -----· -...... _,__ ..• ~- - .. .

. CENTER LINE PLATE. 1/3 LINE LOADING

MODEL SIMPLY SUPPORTED

0.

2

4:

•·a· .. · .. ·

10

0:

2:

'.4•

6

8:·

10·

AVGE·STRAIN

·r~· .

8:9: 83 ......•.

3.98

- 110.05 -,;

·46.85

J •. os

~: 12 ... ·.66 .· ........ .

68.91

6 .95

- a·2.sa

38.59

o. 71

... 12.50

EXPER. STRESS

44.92

1.99

·- 55.02

23.43

1.53

- 6.:33

3.4 •.. 4'6

:3·.48

- 41.29

19.29

O. 36:

~! 6· :25 ......

.c

.L_~.,....___,, .. ..

THEOR. STRESS

38.29

10.23

- .5J .•. :L4

.23·.'9.~·.

·,2.;48.

- :5., 35

27.85'

8.8'9

- 41.62

}~. 72.

0,::6~

-· J-.•. ;1.s

Note! Strains are in micro "/11 ,Stresses in psi, for a load P = 20 lbs •

.,

~:,.-., .. ;.,

.· -· •.- -· .... -, '.~. :: : . .. . ~ :- • .,. ,! •.• - .• ''. -

................. ·•·

, .,.,.., -• .... -, , ., , • •~•••a .. ; ' • • • - •

-91 .. ··-·· ... • ............... "

······•···· .

Page 100: Study of folded plate structure

i

:

I . . ~ r---.. ·-· -- ···--···~-·-----······ --, .. ·--~ .... ---·" .,., - .· .. , ... -.. -- ... . ........ -·- ---- ... ·- ........ _ ·--· .... --- ·-· ··----· .. -9·2 .,JI~ --·- .,... '·- - •, _.,..,_ ___ ---· -- .- -·

"•,V1.,,. ··•111.,;,,,,.;.1_.(; ........ •l'<kM . ._... .. , •. , .... , ....... -. •• L .... _ , ............. ,...~-~ ......... .-.,.-~ ...... ·-.. ---~- - •• ~ . . ... ~-' .._..... .. ....~.,~·--·--'·-... -,•-·•' ··- ........ ... . ... . .. ·,.;;;.; . '....... ..... .,.,-, ~ ,, . .. ...

. ;,:

·····~~ .......... :·::··::-·~ ··.,,.;··.,n

·'

..

...

.,...

CENTER

POINTS

QUARTER

'POINTS

.......

CENTER LINE LOADING

MODEL ON MIDDLE COLUMNS

Q'

4 ..

.. 6

8

·to

0:

:2: . .

10.

r

i,o·:

AVGE STRAIN

- ·6'lf,. 2:2. .. -~'

101.80

- s·o .s"L. • •

.. 6'6:.-.:66 - . . ... ·a7·.-so . . . ..

.. ~ 20 .• 94

- ·4.6.J3.7

10.·34

...... 5:4 .. 64 . . · .

. - 61-79 . .. .

"

'. ~ '·

:~l

-

--

EXPER. STRESS

32. 11

50.90

40.27

33 • 33

·4~. 75:

10.47

- 2J.·.4.4

35.17·

3:3. 9.1

-· -18'.16 .,,

-~

-·-

,: , .;.,_!',

THEOR. STRESS

29 • 18

18.05

31 .• 7-7

"31 . .. ~ 77:

. .

:1.a .• o:.s:

29: .. .18 .. . ~. .

5 :·2-2 .. , .. , ..... 43 .• i68

26.39

26.39

ZJ.68

5.22 f'

Note t Strains are in micro "/", Stresses in ps.i ,. for a load P = 20 lbs •

. ...

. ,._,.:,..._~t·· __ ·;,.-....:.:..:...:,:..,,·-......... :.;.· _.,-.:·--. ..•. '· ,.. - . , ........ _,,._ ··--.--·~·-. -.- ___ >·.··--.- ··-.·.,. . -··--··-·--:··~-~~--·-:·~-

. . . ,. '. -·· . .---· .-··-'· .. ·- - ... , ..... ,_ - ·- .. . ·-·~-- -----···· ... -. .:

er:

.. . ...

• ,-,,, ,;., ,,.1

......... --.·-·_ ·· ___ ··. -·-·-------··· ...

•• ••• • •-••••• •• •"- 0 • .- •• - --...... --- ••- ~ ·-- .. ,.., __ • ·• .4 ,. ·-•·--- ,••fl:,. II '411'-· ,, .,1, __ .,. ....... ,-~ .... ··--~""'4• """' -·•1•, • ..__ .• ,.~__. .. • "' __ .. - ...... °''' ........ I ~ _.. __ • - -• -•·---• _... .• ;... ........ , • -· ..... , .... - •• -· --··- 0• ... ~_;_ ... •--···- ,,,,,·;• • 1••,• --0 ,,...,._ -----.. •••• ... •·, •• .... - ... ...:.-r -0.;, ...... ,_ ···-"'"' • '"·• Y- ........... --•-·""- •••~• ••' '-'•• , ... -~ .. ,~,.-- "" ,.,,., • •• ...... ....... . .,, .. \.a_... . .. .... ·• ..... . . .. . .. .... -

Page 101: Study of folded plate structure

CENTER

POINTS

·Q-UARTER

POINTS ~·

I

~'l.'1111' .... r.~, .. ,,. ,,, , , ......... 11.t,.;rt"-'•..,.., .. ,~.,"'J.\'".·'''""·"'···

.. . . .. ' .. ~' . ...• . ... . •···-·-· ... -· ,.

. . ., ........... --... -,-............. ~ .. -- .... • ...... ,._.,._ .... .

RIDGE #4 LINE LOADING

MODEL ON MIDDLE COLUMNS

..,_ ··-···-

..

RIDGE 11 AVGE STRAIN EXPER. STRESS

THEOR. STRESS

0 ·- 9.37 1!19'' 4.,,.6::8: 4116 .. 2 74.46 :37 · .2t3 . . .. 23.85

-4: - 165. 74 ··-· =:82 .•. 87· - 79. 76 .. . . .

6 40. 73 20.37 25=· .. ·3:2. . .

. ... .

.g·, 28.00 14.00 s·.2·3

.fO-. - 31.09 - 15.55 2.00

:.\·,-:

=o ·- 10. 78 - _.5·.:. 3.9 13.04

2· 79.22 3_9:.61 ...•... 32.82

. _4. - 113.51 ·- ~:~.:.7,5 . - .65.16

6' 30.00· .rs.:qq:. 21.62

8 26.64 13.32 s.oo :10 - 21.4i - 10. 70 - 1.61

Note: Strains are in micro "/11 ,Stresses in psi, for a load P = 20 lbs •

(

b

·1 · '.\ I _ ____....,__. -------.- •·•"'• --,-..--.:..._..;,~ ~ .. ~ .... : ., •. .;;,.·--·-··-~· --~.-. - . ~·'!,.·-.. ---.·-. ~-+..I~ ...... :--:--. • '. -. ··-·--:-.,·-!' /:.· -:---::· -- ·' . .' ·-:.-. ,· . : : -~-·:"":"-~': - ·'"!'" ..... _· -. • .. - '--~-~-------"::"'~---. . -: .- .. ~ ...... ~-":'"!""-~-~··-.--.. ~~·--. '':.": ""'~·-------.... , ___ - - ' , . . . ·. ,:

' I

- -.-. ··-·- --- --·-, ..... - ~··.•· - -·,c·, . ; ;- -~---- ___ ....,._ ----=--,. ~·-- - _, -···· ._. •• ' .. -.,1 ,, ,, .. .., .. - •. • . ' H' .-:-! •. __:_,..::.:.:. .. ·.:·.,. O -~, •._:;_;._~, N.::.. • .'~ •••• ....:._• ••-·N,O oo. • • ·-· ,_..a. ... -•• ... ,. "''"'! ··- ··- 00

0

,,• ;;'"')' - -:- - ON :··· --.- • •o - • • --·

.....

'' 't,IIIIIIL•••·-·' ., • .,..., .......... ,. '~. - ............ ...,_..,...'l'•t._-.. ,,.,• ,._ ................. ---- , ............. ,_,,. •. ,_,,,, .... .,.... ........ , .. -1,N-<>--,.- •-··' • -·-.... ,---. ............ --4,-• -•••• 0 •·••~• • • -------- •• --·•-,••-•••-,.•_'-_ , ... _ .. _,. ••• ' ,,o .. •• ONO ...... , .... •• o,f,,,_,_,_,. __ , •.-••.----•~•••-••·•-'"-.IN••-··-·--·-------·--....... -,.•.~-···' .. 1. .. ' •• ~- •' -. • .. lo' • ......... _. ...... ,, :• w•

,-.. •.

~

Page 102: Study of folded plate structure

I I/

. '•., ...... , _ .. ,..... .. I, • .••• • ...... .,, • ...

I.

I ~94 .

• • ' ~ -· t\-_,. . '. . • .....,._. • •. -:-- ...... .._ __ ~ .·1.-(.· .. , .,.., ___ -- • .. • • - .... , .. : .......... - ...... " ,. ,,-···loll,......... , ··- ·• ....... - ... -.. \A'- ...... , .............. - - "·' . ' .......... -. . ..................... --..~--- -.. -~ .. •· .... .

CENTER

POINTS

QUARTER

POINTS

'' ' '~,

.... ·- ,. .• • .. ......... ,.. ............ , •.t1.•.'

\· .CENTER LINE PLATE 113 LINE LOADING

MODEL ON MIDDLE COLUMNS

AVGE STRAIN

·.·o·· .. .. · . ·6·7:.so . . :2 • 6.06

4. - 122.23

:6.-, 42.11

:s - 19 .13

10: - 25.97

..

0: 5:0 .~t4.

'2' .. . :4 .. ·3·s· ..... :4. :.-. 9·1. 80

·.6 .. 34.30 .__;-~·

8 - 12.81

l() - 15··.Jl

-r

-~

·.-

·-

-

-

EXPER. STRESS

33. 75

3.03

61.12

21.06

·9 56 .. ~ .

:12:· .. ·98, '.' .. .

2·5. .47

2.19'

:45.90'

17.15

6.40

7 .15

-

-

-

-

\

THEOR. STRESS

2.2.12

19.32

52.92

2.3 •. 27

·1 ::5;3 . ... ;

·2 ..• :.SQ

20.09

19.97

41.07

18. 75

0.94

0.49

NOTt··: Strains are in micro "/ 11 ,Stresses in psi , for a load P = 20 lbs •

... ·-- , .... ,

.. .fj

····-· -.

. 'S

..... ·- ·~··--·. ·"": ,,~ ..... _--,.._:·~· .. --::-··:-·· .

" (to.- •••. • .... , ... ~ •.. .......... ...... •

··•·· ·---- - ·--.. -...... ,,.,.. ___ ~· ·-··· .. ·---·· -·-.. ·---·- · • •. ····- ·-· ·-:- -- ·.~-:-.. • ~ ....... --~ ... --····· ..... !~:-'":::.".:-:.:·, ..... ·:-': •. ·., .. ~ --~------- -- ·- ·-.. - --· . ···----·-.. -C.,14~.t- ............. •r ~ ....... •··'• •.. . . •. ----,·-·· .tlllJl!!'lr,1..1.., .. r .. , .- _ ;,r.: .. : ... , .. -.!.", .... _ ............. ···- ..... ~ .............. , ···········- ...... _ . n·-- ..... -..... ~ ........... , .. __ ._ ~~-.------ .. -o·u-.......... , ............. ,, .. ···'· ....• ,;.·

Page 103: Study of folded plate structure

t' -95 ·--'-•- --"--• "-·- • ----· - ------- --••• -- ••- --- ----,- -·--- -·-..,.-• -..---~· ,..__ , I

. .,. ..... "#. ~ .... ~ • .,~, ...... , .... "'.--- ................... ey1,.,... ... ' --·--.·. -- ' -· . -,-.· ........ - "-.• - ••. , •. .........,;4 .... ---.- • - · ....... - ' ......... ---.. ·-.• _.·~··; .......... _.-.-_-.·~--.• ~·.----~---- --··".-~ ·~~ -~.-~--. :...--.-:-··~-:--~--- -- :-- __ .. --: l_. ......................... ~.~!IU..--·--:-~ - , ... ~~----.._-----------.... -----.. -~ . . ' ..

CENTER

POINTS

QUARTER

POINTS

·1' ,, •

CENTER LINE LOADING

MODEL SIMPLY SUPPORTED 1

( WITH TIES )

AVGE STRAIN

:o 47.66 . '<,

2· 4. 76

·4 ~ 21.34

6: ·- 25.28

:8.: 5.74

10:: . . - · .. -. 48.25

·o ·.· ·. 25 • 31

.2: 17.03

\ 4: - 19 37 •

:6: - 17.50

8 20-- 00' . --• .-· ..

10 24-.~_.37

--

-· .-.--.

EXPER. STRESS.

·2·3·. 83 . - ..•... 2.38

10."62

12.64

2.87

24.12

12. 65

8.51

9 6:8· ..•.... -

:.8' • .75

·1.0 •. 00

12. 18

:,

-

-

·-'.

THEOR. STRESS

2.42

4.91

6 49 -· 6.49

4.91

2-42: .. . It ·. . .

:5·. 23": ..

,2._.·47

o.rJ7

O 5:7 :· . :.·_·- ...

2· •. 41

5: 2-3' ........

Note : Strains are in micro "/ 11 ,Stresses in psi , for a load P = 20 lbs •

. .,

..

.·''-'·-:>.-··.· ·'

·-~

~-"; ........ /'.· ·'

"7" .• ·_._ ••. -

I •

.,

I,

. '

1-............... :-:::-:.:.:.:.:: ... :~: -·--· ::.: ... -·:· .... ·:' --·;: ... _ ....... ---·- ...... - . : ................ __ , __ .:.:.::.:. .... ~:.::::.: . .:. ... -- _;:~ ___ ..:.::_:_:; ___ .-:... ..... . ... , .... .. ..-.---·-·'·· . ·---··-· ' '-•·-···------------·--··~---~----•-·A•- ..... •._.,... ___ - ·-·-·· -·-·-···-'"-·--- -·--•••-·· ' ... ,,. ....... ~ .. ,,\., ..... ...,. __ .. .,..,... • . .,.~- -

........ (

Page 104: Study of folded plate structure

-- --· ---··----·--'"-·-----------'"--·-· ........................... _____ ··-·-·-·~·-····--·· _,_ ..

__ •. .. ·-,. -----'---~ ... - .. ,-,_...-. - .. !,._J,~.t!t...;v,.;,: ..• - .... ·--· -..... - f - --.-.-,.,...!:.~.-~ .. ~ ---u~'t!°!~~:~·~-·~.-.._._•'!,• . .__-. ~~~:·'"':...""":.:.,.----~-- - --- -·-·· l!'.'r!~·~-!·: • -··· ·- - -· • .. ~ - .. .. -·--

.....

r,

CENTER

POINTS

·-

:QUARTER

POINTS

.. .,:

RIDGE #4 LINE LOADING

{: ''-

MODEL SIMPLY SUPPORTED ( WITH rr~,~ )

·arn·cm 11 :·: .... ···.

0

2

4

6;

8

10

:o.

:·2

..

·4.·. · ...

6

10.·

AVGE STRAIN

.62.34

26.48

- 116.32

.6._7 • .-6'Q

- ·25 .66

42.34

•.; 91' .• 5.7·

54--61-. .. . .. .•

- 18·:,,7.5

·11 •. so

-

-

EXPER. STRESS

.31.-17

13.24

58.16

33.80

1-2 •. 83 .. .• ~·· .

21 ... 1;.

18.12

18.59

- 48.78

2.t .30 ... ·- ·9·· .• :·37·

s. 7.$ . . ...

-

-

-

THEOR. STRESS

10.87

4. 70

40.60

6~.-6·9_

I

40.066'.

13.17

13.35

8.00

- 23.17

,.

·- ·4_5 .i62, \

Note t Strains are in micro "/ 11 ,Stresses in psi , for a load P = 20 lbs •

...... _ _:._.. ... ·,.--,---···-·· -•·-- ------- - -· -·- _____ .......... -··" ... --· .. --,-· ··--------·--- .. ____ ···-··--·-·· . -r·'· ... -- ---,- -··- .: ... _._:.__ --·~-- -·-····- _·.- .... .,. - ·- -------·--·-

..

-i_.;.

...... , ...... • -··• ··-········----··---•·-~---•--·-" -· - -· ·-·- ·---- - • ., .• _ -·- ------ ---- .•• --·--~--·- ·-•~- ··----·· - ··--------·-•·· ·- ----- __ ..._ _ _. -~ • ., ,... . 'I- .,,.1, ... ·• •••• ...... ,. •• .,~~" ,~-. ... ,.. .,.._..,., .• ,(,.. ~ .,_,. ___ ,,.,. ... ,_,., .. ..-~ ............. ~~~ ,, • '.,,. ,_.,.,.., ....... I,._ ........ -,.-.......... , --· ,·l- .. .,. •, '<,._ J .,_ • ·• ' -~,!? •. .,. •. •· .... ., ..... ~,.~- ... ,.,,.-,~.., • ' -· --- - •

-96 ,.t;,.. • - - . ·- - - .

. .,,,,..-

f?'

f .' ,:~

-·-·--·--···- .. --... .. .

Page 105: Study of folded plate structure

- - ---· .. --- -·· ·---"·-~- .

·,.

CENTER

POINTS

- - . . -- - . . -• . ·- --·- - . . - - -

CENTER LINE PLATE 113 LINE· ·LOADING

MODEL SIMPLY SUPPORTED ( WITH TIES )

RIDGE ·t;

Lr

0

,2

:4

.·(i

=a· . .

10

AVGE STRAIN

128· .:91 . . .. . .. .. . .

.5 .• 3.9

. .;.. . 76.2:~.

67· .. 03: •. . .

15 .. ··15 ... 2:2., •.. 1-9

-

EXPER. STRESS

64.45

2.69

38. 12

34.51

7.57

11.04

,-.-.. ' ' .,, ' ' .,_ -""·'...- ~

- -- -~ ..... ·- --- ·- ···---~ .... - -- .. ,--. ·------ - -- - .. - .

-

..... , . ··-··

THEOR. STRESS

49.67

10.32

38.03

39.07

18 •.. 06

: .. ,

5·. ·53 ... • ••

-97

~.

'!

;o. 71.40 35 .• 70· :~l-8.3.8· 'I !

~ ..

. ~ .... - - --- --- - -- . - ... -. --_· .. ~----

QUARTER

POINTS

::2

·4

6

·8

10

~

·-

-

0.54

73.75

36.79

2.80

12.96

~'.

..

-

0 .• 21

.36. 87

18.39

1.40

6.48

- 11.31

- 26.69

34.67

- 19.52

7.34

Note! Strains are in micro"/" ,Stresses in psi , for a load P = 20 lbs •

-~, .... -·. -_ - . ~ "-·.·· ~----·:··--"--;··-i.:.·"''':'·--,.····:.--::-. ·-· ,....,,,-:--~~·-.-,-.·-'i. .... . - r - --- . . - - --···-·•"" . ... ---~;.. ..... ~ _ _. __ ..... ..... .: .• -...~ ... :.~·-·~ ......... ~-..: ... -.,:. • ..:..... ••........• _. ·-· .; •. ,; .... :;-._. ',-: .. · .. -·----:--"-·••--:------=~ ... _;.,- - ...:. . ..:---- ___ .._ -., .... - .,., ·~·-·-·- ... _:''"'--•·--:.-:---·- ·---·

l .. . .. ... ······ l \, .,,....,. ._,.,..,.~ ....... ,-~.,,....-.-.,.,__.- __ , ____ •• ,...--~-·•---.. ~••••••,.,._., t<t,, ,.,,.,., _,..._ • ..,_ •·••• __ .... __..- .. ,,,~,.,,u,, .. ,.. "'"''' ,.'f.,,,,..,., .. ,,l,_,_u., ... ,. ..... ,,.......,_, - •· > ~, -·------ ---··- ............. ~--... • ",,..,. ,-,.-.,.,..,._,..,.,-.. -•"'-•-··-•'"·'•--•-•••·,,_,__,,.,~•-••- - ,-., .. ,- .. ,,.,, _ _..._.,..,~-·,'4·• ,.,I o•L-••-• .,_..,.,"" ·-· h''"·•••·•-··------ ·•·- , • •-•-,•~---··"•••··"·'"·"''' •'·••-• •·--••·•••·•'""'' .... ,~,..r_._, l ,·

l

j (

l

Page 106: Study of folded plate structure

--.~ . .: _ _,.__•;,,:.-- • .;;..>, ............. ' _ _.,,._·, ... --. . ........ -~--- , __ , .... _.......,__. ____ . ·-· . - .. ~- '--·"••·•··--·---·---...- . ·- .. --· ... ___ ; ...

;,

. ' . - ... ,_.. - ....... ·-·-.... . ... -98 i>

-~-

CENTER

POINTS

QUARTER

POINTS

. . . ' .. ~

CENTER LINE LOADING

MODEL ON MIDDLE COLUMNS ( WITH TIES )

RIDGE fl

:()

2:

4

6

s:-.

10

0

2

·4

'6

:a ·1·n :· ·.-:~u·

·'

;"""

:al!'

·-

~

-

12.19

6.72

19.45

17 .96

12.68

15. 62

9.84

18.44

17.50

18.54

12.03

-

-

-

~

-

EXPER. STRESS

6

6.09

3.36

9. 72

8.98

.34

7.81

8 36 ...•. ,.

4.92

9.22

B. 75

9.37

6.01

..

-

-

. ... . ..

THEOR. STRESS

59.71

44.29

14.06

14.06

44 ... :2~)' . . .. '

5"9. 7:l·

:26 .• 79

- 17.19

3.82

3~82

- 17.19

Note : Strains are in micro "/u ,Stresses in psi, for a load P = 20 lbs.

'7-- ·,

l.' ,_,

;._ ·--·~- ·- - ·_ ··- .. , --· .: ...

~•••,._, ·- ••'· --R••-•··•-.. ·••'·• ·"''"" i••-•"'..,.'''·:•·•., .. ;~•,•,I_,,.,,,_,. ... _.,,,..,.., __ ,._ fUI'"' .. ,,.,. __ ,,..,.,..., .. ,, •. ..., •• _ ..... ~.·-"'"., •. ,... ~~.._._.,..,...,~ .. ,_..,._,..,.,..,..-, ..... ..,,_._._.._....._ _ _._~.,_:._ .... ,,. ... ,,._,::.:..·::;:~ •• :.:: •. ..,.:·:·.,,,..,,,. ..,:...::::~::,::=-.:,:·:-: .. ~.-~,:,,.:.:.~ ... -....,.-----.. ,,,.,,.,_.., N~lw .·-...,.,- ,..,,_,.., . .,,.._..,..,.,._.,_,,i... ,.-...,..,.,..,..-.le.. .... -,..,,_,....,.~-----·._ _____

I 'i, •

- : ·' 1

ii ,. - .. :..:

·- :. .. ,.. .. .

... :·"1'. .;.i ·~, ,:

·) -,,1

' ':J

I ;"1'

i

l. I \

i

' ,,

~ . .I

I

!

.,

1 • l l

! I

i I 1 I I i a

I l

. l .. 1

I'

-· - ·---····· J. ' ! l .1

' ~" '...', ;·t

:;, :j

l j

I I '

Page 107: Study of folded plate structure

i I

'1 . I . )

I

I i

,.,,. .• .

CENTER

POINTS

:.QUARTER

POINTS

;, ....

-· . --- -·-----., -- --·- . ----- .... - - w • ' • _.,.,

..... w ..... - _ ....... --.. -..· , •• ,.,,, • • • • ...... ·-·:· .... •• w •

w .... _•

.,'., .. , ............... ,

"''"····>- ~-.1, .. ( •

· · RIDGE /14 LINE LOADING

MODEL ON MIDDLE COLUMNS ( WITH TIES)

RIDGE #

,0.:

'2

4

6.

a.

10:

0

4

. 6

:8:

10

AVGE STRAIN

57.66

32.89

- 114.69

78.00

- 19.84

32.03

·28 75 ... ,~.

-38.09

- 90.70

65.54

- 14.84

21.56

-

-

EXPER. STRESS

26.83

16.44

57.34

39.00

9.92

16.01

I4·'_, .. 3·._.7··· . .•... 19:.()4_. . ' ..

- ,45 ... ·3·5 ......

·- 7 .42

10.78

..............

--

-

: .. ,, .,. ... •\ ' .... ' ..

THEOR. STRESS

72.25

31.39

36.57

68.51

·s3.52

33.10

43.14·

- 2.~ •. 9~·

- -2·2._45

64.33

- 52. 75

28.49

Note : Straias are in micro "/11 . Stresses in psi , for a load P = 20 lbs. '

-99 " ,1,1 ... •, .. ,,,._:- .·•

Page 108: Study of folded plate structure

I

- - - ___________________ __.,___._ ____ ~--.--·---- ----- --· ----------- --·-----~-

CENTER

POINTS

"

QUARTER

.POIN~tS

·: ......... ,#•,·•·· ,·- -:·.

, .. ., .. . ' .. ' ··~--··-................ ,,,,. . ~ .......... ;•.•.•'":... .._ :.... .. .,, . • ••• . ................... _.- ... - .... ....-. .. t:t ... ..

CENTER LINE PLATE 113 LINE LOADING

MODEL ON MIDDLE COLUMNS ( WITH TIES)

RIDGE ffo AVGE STRAIN ·

o·: ,.9e.,,_:12:

'.f ·6~·ao

4 ~ .. 8'5' ·203 .... 6/" 60.92

8-: ·- 0.77

10 4.69 . ;' - '. .

o· 43.44

·2· 12. 75

·4 •.. .-. - 68. 14

,6. 43.98

8 - 4.29

10 ,_ 0 .78·: ...•...

-

=-

~~-

-·-

EXPER. STRESS

49.06

3.40

42.61

30.46

0.38

2.34

21.72

6.37

34.07

21. 99

2.14

0.39

--

-

-

-

•.• "'·,,, ........ I,

THEOR. STRESS

33.00

1.23

37 .81

38.37

.22 .•. (18'.

:12.-35

J"o·· 61 . . . ... i:.·:23

·26 13 . .. , ... · ... J:a,~;6·:a

2·1 .•. 14

l0:_.:03

t ' \.

Note: Strains are in micro"/,,, Stresses in psi, for a load P = 2o lbs •

· .

.....

'>.· ·.~. ••)•., ....

. -·.··:··- ,_ . ., •,• •• •,: ,, ,:,~• .. ," ,• 0 ,· 1".•••~I ! -.,. ,, H.0 ~-·-~ > • . •. ,; .. "· ;;, .. :.:----.. ·.· .... ,; -~-"-,-.--·"· .. -·----~-.. _, .... ,,..... --~-· . . -'--·-...:.:.---·-'··"'-'-··-

. -100.

~

. r •.

.I ! '

I ,

i,. ••_:_:~• •• ,,. .. - ....._.._. • .,.._ ~ ... -:,.,. • '·-~.~.:::_'_ ___ ·, .. .:._ __ ~ .......... - ... ··- ,_ .... -.-,-... ---.... - ... - ... - .. ..----..--. ~---.,. ........ ....__, __ _. ... _.,,. .. ___ ""' ..... -- .... --... ~··••··-------~-·- ..... ,, .......... -... ... -·--·· f'W"."'lW- - , .

. - ·-·; -----:.s-.. .:.-· --· ·--... . I' . t .

' i

·--·----........... ~.::.::._-,,-•_ ........... -..... _..,_ .... ,, ......... - .. ~,.. ........... -... .......... --RO --· .. -----·- - '·r ' i

i ' I

l I

I

I

I

Page 109: Study of folded plate structure

b

·r t -;···,,~., , ::. ; ! : ..;: 1 f<li' I;_ H MS : V 1 ,..-- -,-,--~ ' .. --II

··----· .. ----·---·---·-----•--' - -----·---------- - . --··· -- ·- - -- - - - -· -- -- -------- ----- - -..... -···-- ---~ - --- - .. ~-··--·- ·101 · ... ,. ---1 ""1· '' .. ··...:

--- --------~- ... --... , .. __ ·~--- -- ---.. ,,

• ....... .-. ... ._. ...... ~·- ... . ..... .,.., ... .... ·~4~·-,.~

'

.. ,• .,. :, . .,..,.,,-,.,.,.,, . -~ .. _

'' I ,&, ,.,,1•••• •• •- •·•·• ......... -~ .•. , ..... ' .... ' ' . . ·- ..... " ......... "~··, ...... ~~·-,,.,..~ -·· •.. -........

ll E F E R 2 N C E S

I. Yitzhaki, D. "PRISMATIC AND CYI..INDRICAL SHELL ROOFS", Haifa Science Publishers, Haifa, Israel, 1958

Simpson, H. ''DESIGN OF FOLDED PLATE ROOFS", Proc. ASCE Paper 1508, January 1958

. (-··

3.. Winter, G. and Pei, M. . ''HIPPED PLATE CONSTRUCTION'', Journal AMerican Concrete Institute, Proc. Vol. 403, January 1947

4;!1 Craemer, H.

5.

''DESIGN OF PRISMATIC SHELLS", Journal American Concrete Institute, Proc. Vol. 49, February 1953

Ashdown, A. J. "THE DESIGN OF PRISMATIC STRUCTURE", ' Concrete Publications Ltd., London 1951

Zanoni, E. A. ''MODEL STUDIES OF A FOLDED PLATE STRUCTURE", Fritz Engineering Laboratory, Lehigh University, 1962

Scordelis, A. C., Croy,~. L. and Stubbs, I. R. "EXPERIMENTAI. AND ANALYTICAL STUDY OF A FOLDED PLATE", Journal of the Structural Division, Proc. ASCE, December 1961

.. \"

-~-

_. -· ;,,:

·~···. - ·····: ·--···· ;·,··-· .·. ·- ...

,.

"• • .... ,. ·; •---:-r•,·-•-.. '". •··-- .---· -,;-- _ . ..., ,· -·--.--------• .... - . ·--~· - ' . - --•- .. ·. ,,,-..,_,. __ - ~---, . .-s.~,- ' - . i.. - ~- -.. ;. .•.•

',. I.. '., ~~····--·· ---·-----.-- ------- ·-, --~-"~ ....... --·- .... ----.--......... -----------------___ ... _________ -----·------ ... _____ _....,. _______ ..,..... .. _~ ~ ............ --~ ...... ll;"'" ----- ' - .. -----:-::- ·---~ _ ....... -.... •• ·-:---· --J..'•----...... , .... ,_ ... ~ .. -· -~~·f'"-~ - -·---;_-~-_-... _ .. _.,._~~-:.~t~~"""- -

Page 110: Study of folded plate structure

- ., -- - .--- - .-------~~--~----- -· --- ·---- ---- ---- -···-· ----·-------- -·------· -------- .--- --- - -. --10-2--·· . . .. ~-- -·· ,- __ ........,_____ ---·'II;.:,- -- ....... - -.. •.,~' . . .... . , .. , .... ,. .. ····, ·-·

..... _______ ...... . ·- ·"·· .fJII/IIIIIIJt,. .. .•.. -

...

.\ ........ .i\S:· •'..... .'. ..: •.• -~.:.;: ·-.... ···,

~· .... .,,.. ,ri,..t(,....• ......

•:

- ·-··· ......... . ······•· .......... __. ........... , .. ·- ..•. .

VI TA

The author was born in Mezieres (France) February 10, 1939.

Be was graduated from the Lycee Chanzy in Charleville (France) in

June 1957. He then attended the Institut Catholique d' Arts et

Metiers in Lille (France), from October 1957 to June 1961. There he

received the Diplome d' Ingenieur I. C. A. M. in June 1961. He

came as a Fulbright Student to Lehigh University, Bethlehem, Pa.

Later he was awarded a Research Assistantship in Civil Engineering

at Fritz Engineering Laborator~. He began studies for a Master's ..

Degree in September 1961.

. .

. •;_S: .·. ''iii

:1 ..

• .

.. .-.---·~

----:- ::-.·.- ....

....... .-.,· .... :·· .. --~~-·_ .... _: : .. ' ... - . ...... ,.,.·~:· , :, "'.'•-•.i.·• • . ~ ,•,at~,. ]"• • :• ., .. ,.;. ~ ,. ._.._ ..

. .. -..,,,- ... • ...... ,... _________ , __ ~.-- -·---. -· - • ··10- ......... -' •· ............ ,. •.•. •. ~' }"~ ........... - . ...... -..... ---·-·· --··· . ·-·····" .

.._,-.---,_,_. .