analysis of stress concentration of hybrid composite with a central circular hole subjected to...

8/11/2019 Analysis of Stress Concentration of Hybrid Composite With a Central Circular Hole Subjected to Tensile Loading

1/5

Abstract This work describes about thestress concentration in a rectangularspecimen with a circular hole made up ofhybrid composite material with thecombination of glass/carbon with epoxy. Thearrangements of cross ply lamina in thesequence of alternative carbon and glass asusing carbon bre and in panel gives morestrength to the structure as the carbon

properties are high when compared to glass.

Typical aircraft and automobile componentsare with cutouts and such cutouts reduce theweight of the aircraft according to the weightreduction law and also it reduced the bulkingload carrying capacity. !xperimentalinvestigations were carried out using threespecimens as per A"T# $%&'' in the(niversal Testing #achine. "tressconcentration in the rectangular specimenwith a hole is also analy)ed using *!A andcomparing the results.

+ey points, composite- nite elementanalysis- stress concentration- tensile

strength.

I.INTRODUCTION

A material with a circular center hole under

transverse loading condition are widely used in

all application in diferent eld o! industries and

engineering application as space vehicle "

aircra!t" automo#ile" marine etc. The circular

cutout is introduced in a part to !acilitate with a

$oints in such case stress concentration !actor

%&C'( is increases near the hole due to loading

condition. &C' increase creates a change in theuni!orm stress pattern in the entire part and

may lead to !ailure. )y#rid composite are

composite with two diferent properties

com#ining together to give more strength at

low price "use o! car#on #er alone may #e

e*pensive to manu!acture in case o! using a

hy#rid composites o! car#on and glass !or the

re+uired part is needs to #e studied. ,any

researchers have analy-ed the case in diferent

manner a#out stress concentration with circular

holes.

.

II.IT/RATUR/&UR0/1

,oon et al. 234 evaluated the stress eld and

relationship #etween isotropic and orthotropic

composite plate su#$ected to transverse

loading. It has #een analy-ed stress in *y

direction is seen ma*imum on the hole

#oundary along the width direction o! the plate.

1asar and arslan 254 has studied the coupling

efect #ehavior is diferent in laminatedcomposite plate #ehavior with hole !or two

cases in which one is single layer and other

layer in composite plate #oth having same

material properties and #er orientation angle.

6ain and sanyal 274 analy-ed &C' !or all stresses

increased slightly with increasing o! t8A at any

D8A ratio !or almost all cases o! material. The

t8A ratio plays a signicant role in orthotropic

plates and neglia#le role in isotropic plate and

7D analysis is most suita#le !or orthotropic

material.. 9an et al. 2:4 proposed a general

solution !or the composite laminates with a

hole using ;/, %#oundary element method(. It

has #een shown that even with a very coarse

mesh the loop stresses along the hole

predicated #y the presence !ormulation are

very close to the analytical solution. Neha and

mohite 2


2/5

III. D/&CRI9TIONO'9RO;/,

To study the stress concentration !actor

around the hole in orthotropic specimen model

specimen with dimension o! 7>5. The specimens are su#$ected

to uni!ormly distri#uted load with 9. The

specimen is !a#ricated #y arranging glass andcar#on #er alternatively Beeping at the top

and #ottom with glass #er. Tensile testing and

'/A so!tware analysis to nd out the stress

concentration !actor near the hole o! the

specimen.

Ta#le 3F

The material properties o! the orthotropic

specimen

I0. /9

/RI

,/

NT

A

T/&TING

)y#rid composite laminate plate preparedusing glass and car#on #er with epo*y resin.

'a#rication o! the plate is a com#ination o!

glass and car#on. The glass lamina is placed on

top and #ottom o! the plate and in?#etween

alternative o! car#on and glass lamina were

placed one over the another with application o!

epo*y. Totally 33 layers are used to !a#ricate a

plate with the si-e o! 7EEmm *7EEmm.

'a#rication done #y using vacuum #ag

techni+ue and this method gives a proper

nishing to the sur!ace. &pecimens are

dimensioned #y water $et cutting machine asper A&T, standard.

'igure3 F tensile test specimenIn aircraft there are various force acting on it and vertical

and horizontal force with an opposite force that type of

forces act on aircraft so to find these type of loading in

aircraft using tensile testing. Tensile testing is a form of

pulling a specimen on both the ends. Due to elongation it

measures displacement with respect to force act on it.

'igure5 /*perimental &etup In UT,

A!ter cutting a specimen the ta#s are

attached to it #y epo*y resin with mm and the gauge length o! 3

/77 %Gpa( 3< =.>

H35 E.5< E.5=

H37 E.5< E.5=H57 E.5< E.5=

G35 %Gpa( 37. 7.=G37 %Gpa( 37. 7.=

G57 %Gpa( > 7.=


3/5

0.'INIT///,/NTANA1&I&

'inite element method was chosen to

analysis the orthotropic specimen. The

structural element used 7D shell element"

:node 3=3 in AN&1&. ,apped meshing were

gives more efective to nd the stress

concentration near the hole. The !ull specimen

was analy-ed with a specied dimension.9urpose o! using '/, is to nd the e*act place

o! the ma*imum stress near the hole. The

layup o! the material are also mentioned as per

the procedures with the same thicBness % gure

7(.

Figure 3: composite laminate with central hole under

study with boundary conditions

Figure : mapped meshing around the circular hole

!fter created meshing on a specimen " near the hole

need to create fine meshing to #now the e$act value of

stress around the hole.

%I. &'()*T!+DDI(,)((I-+

The result o! tensile test #y e*perimentaltesting is o#tained !or the material is presented

in graphical e*planation !orm%gure .=7 ,9a at the load o! 57JN.

1oungs modulus where is more when compare

to glass and it is less than car#on specimen. Its

gives an intermediate value o! youngs

modulus.

Figure /: stress vs. strain curve for tensile test

3


4/5

Figure 0 :*oad vs displacement

Figure 1: time vs. strain

Ta#le 5FpeaB stress

s.no Trail 3

%,9a(

Trail 5

%,9a(

Trail 7

%,9a(

Avg

%,9a(

EE8EE 5>.> 5=.>< 5=:.= 5=>.=7

Ta#le 7 F peaB load

s.no Trail 3

%JN(

Trail 5

%JN(

Trail 7

%JN(

Avg

%JN(

EE8EE 55.= 57 57.: 57

Ta#le : F youngs modulus

s.no Trail 3

%G9a(

Trail 5

%G9a(

Trail 7

%G9a(

Avg

%G9a(

EE8EE 3< 3 3:.=

analysis of stress concentration of hybrid composite with a central circular hole subjected to...

Documents