a common sense approach to stress analysis and finite ... · agenda a common sense approach to...

A Common Sense Approach to Stress Analysis and Finite

Element Modelingg

February 28th, 2008

AgendaAgendaA Common Sense Approach to Stress Analysis andA Common Sense Approach to Stress Analysis andA Common Sense Approach to Stress Analysis and A Common Sense Approach to Stress Analysis and

Finite Element ModelingFinite Element ModelingFebruary 28February 28thth, 2008, 2008

8am PST (Los Angeles) / 11am EST (New York) / 4pm GMT (London)8am PST (Los Angeles) / 11am EST (New York) / 4pm GMT (London)

Welcome & Introduction (Overview of NAFEMS Activities)Welcome & Introduction (Overview of NAFEMS Activities)

Matthew Ladzinski, NAFEMS North AmericaMatthew Ladzinski, NAFEMS North America

A Common Sense Approach to Stress Analysis and Finite Element A Common Sense Approach to Stress Analysis and Finite Element ModelingModeling

Bob Johnson BSc MSc NRABob Johnson BSc MSc NRA MIMechEMIMechE CEng DAMT LimitedCEng DAMT LimitedBob Johnson BSc MSc NRA Bob Johnson BSc MSc NRA MIMechEMIMechE CEng, DAMT LimitedCEng, DAMT Limited

Q&A Session Q&A Session

PanelPanel

Closing Closing

www.nafems.orgwww.nafems.orgLadzinskiLadzinski JohnsonJohnson

THE INTERNATIONAL ASSOCIATIONTHE INTERNATIONAL ASSOCIATIONTHE INTERNATIONAL ASSOCIATIONTHE INTERNATIONAL ASSOCIATIONFOR THE ENGINEERING ANALYSIS FOR THE ENGINEERING ANALYSIS

COMMUNITYCOMMUNITY

An Overview of NAFEMS NA Activities

Matthew LadzinskiMatthew LadzinskiNAFEMSNAFEMSNorth American RepresentativeNorth American Representative

www.nafems.orgwww.nafems.org

Planned Activities in North America

WebinarsNew topic each month!p

AUTOSIM UpdateApplied Element MethodsManaging FEA in the Design Process

R t biRecent webinars:The Interfacing of FEA with Pressure Vessel Design Codes (CCOPPS Project)Multiphysics Simulation using Directly Coupled-Field Element p y g y pTechnologyMethods and Technology for the Analysis of Composite MaterialsSimulation Process ManagementSimulation Process ManagementSimulation-supported Decision Making (Stochastics)Simulation Driven Design (SDD) Findings

T i t f i bi t i t bi


To register for upcoming webinars, or to view a past webinar, please visit: www.nafems.org/events/webinars


EventsPractical Stress Analysis & Finite ElementPractical Stress Analysis & Finite Element Methods with Bob Johnson

An opportunity to ensure that your organization gets maximum benefit from using FEAgThree-day Training CourseApril 30th – May 2nd, 2008 in Troy, MIOnly a few open seats are still availabley pwww.nafems.org/events



NAFEMS NA 2008 Regional SummitNAFEMS 2020 Vision of Engineering Analysis and Simulation

NAFEMS 2020 will bring together the leading visionaries, developers, and practitioners of CAE-related technologies and business processesGoal: Provide attendees with the best “food for thoughtGoal: Provide attendees with the best “food for thought and action” to deploy CAE over the next several yearsLocation: Embassy Suites Hotel & Convention Center,

Hampton VirginiaHampton, VirginiaDate: October 29-31, 2008

Call for Papers Now Open!Call for Papers Now Open!Call for Papers Now Open!Call for Papers Now Open!

For more information visit:For more information visit:


For more information, visit: For more information, visit: www.nafems.org/nafems2020www.nafems.org/nafems2020

Other NAFEMS Activities

NAFEMS Simulation Data Management Working Group (SDMWG) – name tbdg p ( )

www.nafems.org/tech/sdmwg

NAFEMS NA eNews UpdateMonthly newsletter containing information on upcoming NAFEMS NA activitiesCan be downloaded at: www.nafems.org/regional/north_america/enews

E il f NAFEMSEmail from NAFEMS


A CommonA Common Sense Approach to StressSense Approach to StressA CommonA Common--Sense Approach to Stress Sense Approach to Stress Analysis and Finite Element ModellingAnalysis and Finite Element Modelling

A NAFEMS Webinar organised by Matthew Ladzinski of A NAFEMS Webinar organised by Matthew Ladzinski of NAFEMS Limited (North America).NAFEMS Limited (North America).

Matthew Ladzinski@NAFEMS OrgMatthew Ladzinski@NAFEMS [email protected]@NAFEMS.Org

Presented by Bob Johnson BSc MSc NRA MIMechE CEng Presented by Bob Johnson BSc MSc NRA MIMechE CEng DAMT Limited, UKDAMT Limited, UKDAMT Limited, UKDAMT Limited, UK

[email protected]@damt.co.uk

SLIDE SLIDE -- 88 --

A CommonA Common--Sense Approach to Stress Analysis and Finite Element ModellingSense Approach to Stress Analysis and Finite Element Modelling


••Achieve a modernAchieve a modern--day balance between hand calcs and FEAday balance between hand calcs and FEAAims:Aims:

••Provide a number of “mustProvide a number of “must--have” formulas for stress analysishave” formulas for stress analysis

••Provide a summary of the technique of FreeProvide a summary of the technique of Free--Body DiagramsBody Diagrams

••Practical advice for best use of FEA for realistic solutionsPractical advice for best use of FEA for realistic solutions

••Constraints that gives minimal support & worstConstraints that gives minimal support & worst--case stressescase stresses



CONTENTS:CONTENTS:CONTENTS:CONTENTS:••INTRODUCTIONINTRODUCTION

••PLANET EARTHPLANET EARTH••PLANET EARTHPLANET EARTH

••FORCES and MOMENTSFORCES and MOMENTS

••TYPES OF STRESSTYPES OF STRESS

••PRINCIPAL STRESSESPRINCIPAL STRESSES

••FREEFREE--BODY DIAGRAMSBODY DIAGRAMS

KARABINER FEA (O G )KARABINER FEA (O G )••KARABINER FEA (Open Gate)KARABINER FEA (Open Gate)

••DETERMINATE or INDETERMINATE?DETERMINATE or INDETERMINATE?

••KARABINER FEA (Closed Gate)KARABINER FEA (Closed Gate)KARABINER FEA (Closed Gate)KARABINER FEA (Closed Gate)

••MINIMAL CONSTRAINT METHODS IN FEAMINIMAL CONSTRAINT METHODS IN FEA

••QUESTIONS and CLOSEQUESTIONS and CLOSE



INTRODUCTION:INTRODUCTION:INTRODUCTION:INTRODUCTION:



PLANET EARTH:PLANET EARTH:PLANET EARTH:PLANET EARTH:Polar Radius = 6356.8km

Equatorial Radius = 6378.2km

M R di 6371 0k (3960 il )

One metre defined as 1/10,000,000th of hi di *

0.25 x (2 x pi x 6,371,000) = 1.00075m 10,000,000

Mean Radius = 6371.0km (3960miles)

Surface Area = 5.101E14 m2

Volume = 1.083E21 m3

M 5 977E24 k

this distance*

Mass = 5.977E24 kg

Mean Density = 5517 kg/m3

Gravity at Surface = 9.80665 m/s2 (standard 45deg)

Rotational speed 465 m/s (at the equator)Rotational speed = 465 m/s (at the equator)

Sun orbit velocity = 29,780 m/s (mean speed)

Inclination = 23 27 (equator to ecliptic)

Greatest Height = 8847 7m (29 028ft) Mt EverestGreatest Height = 8847.7m (29,028ft) Mt Everest

Greatest Depth = 11,033m (35,960ft) Marianas Trench

Land Area = 148.8E6 km2 (5.747E7 miles2)

Ocean Area = 361 3E6 km2 (13 95E7 miles2)

Composition of Atmosphere (by vol) N2 78.09% O2 20.95% Ar 0.93% CO2 0.03%Ocean Area = 361.3E6 km (13.95E7 miles ) Ar 0.93% CO2 0.03%

*One metre defined as 1,650,763.73 wavelengths of the krypton-86 atom



PLANET EARTH:PLANET EARTH:PLANET EARTH:PLANET EARTH:

DIMENSIONALQUANTITY SYMBOL UNIT SYMBOL UNIT SYMBOL

S.I. UNITSS.I. UNITS U.S. UNITSU.S. UNITS

QUANTITY SYMBOL UNIT SYMBOL UNIT SYMBOL

Mass M kilogram kg slug -

Length L metre m foot ftBase Units

BaseTime T second s second sec

Force F newton N pound lb

Base Units

An absolute system because the

A gravitational system because the base

mmeasurement of the base quantity mass is independent of it’s

i

quantity force is the weight acting on a standard mass (at seal l d 45d l i d )environment level and 45deg latitude)



PLANET EARTH:PLANET EARTH:PLANET EARTH:PLANET EARTH:g = 9.81m/s2

m TX TX TY TY TZ TZ RX RX RY RY RY RY RZRZ

mY

XZSLIDE SLIDE -- 1818 --


PLANET EARTH:PLANET EARTH:PLANET EARTH:PLANET EARTH:g = 9.81m/s2mg

m TX TX TY TY

R TZ TZ RX RX RY RY RY RY RZRZ

Y



PLANET EARTH:PLANET EARTH:PLANET EARTH:PLANET EARTH:g = 9.81m/s2mg mg

m mm TX TX TY TY

R m x.... TZ TZ RX RX RY RY RY RY RZRZ

Y




m mmmg

TX TX TY TY

R m x....mm

mgTZ TZ RX RX RY RY

m x....D’RY RY RZRZ

Y




m mmmg

TX TX TY TY

R m x....mm

mgTZ TZ RX RX RY RY

m x....D’ mg

RY RY RZRZ

mmY

DXZ



PLANET EARTH:PLANET EARTH:PLANET EARTH:PLANET EARTH:xx

θθ

TimeTime tt tt

DiDi θθ

QUANTITYQUANTITY LINEARLINEAR ANGULARANGULAR

DistanceDistance xx θθ

VelocityVelocity xx θθ

AccelerationAcceleration xx θθ

.. ..

.... ....AccelerationAcceleration xx θθ

InertiaInertia MM I (I (ΣΣMrMr22))

“Effort”“Effort” F = M xF = M x T = I T = I θθ.... ....

MomentumMomentum M xM x I I θθ

Kinetic EnergyKinetic Energy ½ M x½ M x22 ½ I ½ I θθ22

.. ..

.. ..



FORCES and MOMENTS:FORCES and MOMENTS:FORCES and MOMENTS:FORCES and MOMENTS:




10kN10kN

21kN Closed Gate Rating21kN Closed Gate Rating

2 14 tonnes2 14 tonnes10kN10kN 2.14 tonnes2.14 tonnes4720 lbsf4720 lbsf

7kN Open Gate Rating7kN Open Gate Rating21kN21kN 21kN21kN gg

10kN10kN

7kN7kN 7kN7kN




i)i) MAGNITUDEMAGNITUDE

DEFINITION OF A FORCE:DEFINITION OF A FORCE:

Y


ii)ii) DIRECTIONDIRECTION

iii)iii) POINT OF APPLICATIONPOINT OF APPLICATION

7kN7kN7kN7kN

X

Y

XZTX TX TY TY TZ TZ RX RX RYRYRZRZ




FORCES

∑Fx=0MOMENTS

∑M 0∑Fx=0

∑Fy=0∑Mx=0

∑My=0∑Fz=0

∑ y

∑Mz=0YTX TX TY TY

XZTZ TZ RX RX ZRY RY RZRZ




Y7kN7kN7kN7kN

X

Y

7kN7kN7kN7kN

XZTX TX TY TY 7kN7kN7kN7kNTZ TZ RX RX RYRYRZRZ




FORCES

∑Fx=0MOMENTS

∑M 0∑Fx=0

∑Fy=0∑Mx=0

∑My=0X

Y

Z

7000 7000 –– 7000 = 07000 = 0

∑Fz=0∑ y

∑Mz=0YTX TX TY TY

XZTZ TZ RX RX ZRY RY RZRZ



FORCES and MOMENTS:FORCES and MOMENTS:

∑Mz=0

FORCES and MOMENTS:FORCES and MOMENTS:

Y7kN x 19.5mm 7kN x 19.5mm –– M = 0 M = 0

∑Mz=0

M 7kN 19 5mmM 7kN 19 5mm7kN7kN7kN7kN

X

Y M = 7kN x 19.5mm M = 7kN x 19.5mm +ve+ve

7kN7kN7kN7kN

XZM M 7kN x 19.5mm 7kN x 19.5mm e = 19.5mm e = 19.5mm TX TX TY TY 7kN7kN7kN7kNTZ TZ RX RX RYRYRZRZ




Y7kN7kN7kN7kN

X

Y

7kN7kN7kN7kN

XZ7kN x 19.5mm 7kN x 19.5mm 7kN x 19.5mm 7kN x 19.5mm TX TX TY TY 7kN7kN7kN7kNTZ TZ RX RX RYRYRZRZ



TYPES of STRESS:TYPES of STRESS:TYPES of STRESS:TYPES of STRESS:

TensionTension CompressionCompression Shear/TorsionShear/Torsion BendingBending




Y7kN7kN7kN7kN

X

Y

7kN7kN7kN7kN

XZ7kN x 19.5mm 7kN x 19.5mm 7kN x 19.5mm 7kN x 19.5mm

7kN7kN7kN7kN




FF FF

QQMM

SIO

NSI

ON

ESSI

ON

ESSI

ON

TEN

STE

NS

CO

MPR

EC

OM

PRE

TensionTension CompressionCompression Shear/Shear/TorsionTorsion BendingBending

F F F F Q Q M M POSITIVEPOSITIVE NEGATIVENEGATIVE

σσ = F= F σσ = F= F σσavav= Q= Q σσ = My = My IIAA AA AA




FF FFbb

QQMM

dd

ØØDDXX

YY

XX

YY

SIO

NSI

ON

ESSI

ON

ESSI

ON

dd XX XX

TEN

STE

NS

CO

MPR

EC

OM

PRE

I = bdI = bd33

1212I = I = ππDD44

6464

TensionTension CompressionCompression ShearShear BendingBending


1212 6464

y = d/2y = d/2 y = D/2y = D/2




TYPES of STRESS:TYPES of STRESS: σσ = My = = My = 7000x19 57000x19 5x5 5= 1045MPa x5 5= 1045MPa MOMENTMOMENTTYPES of STRESS:TYPES of STRESS:

ØØ11mm11mmσσ = My = = My = 7000x19.57000x19.5x5.5= 1045MPa x5.5= 1045MPa

I I ππ(11)(11)44/64 /64

Y

151,500 psi151,500 psi

7kN7kN7kN7kN

X

Y

7kN7kN7kN7kN


Shear/TorsionShear/Torsion7kN7kN7kN7kN

σσ = F = 7000 = 74MPa = F = 7000 = 74MPa A A ππ(11)(11)22/4 /4



TYPES of STRESS:TYPES of STRESS: σσ = My = = My = 7000x19 57000x19 5x5 5= 1045MPa x5 5= 1045MPa MOMENTMOMENTTYPES of STRESS:TYPES of STRESS: σσ = My = = My = 7000x19.57000x19.5x5.5= 1045MPa x5.5= 1045MPa

I I ππ(11)(11)44/64 /64 DIRECT DIRECT STRESS STRESS PROFILEPROFILE

+/+/--

YM M

PROFILEPROFILE

7kN7kNFF

X

Y

7kN7kN

XZ 7kN x 19.5mm 7kN x 19.5mm

Shear/TorsionShear/Torsion7kN7kN

σσ = F = 7000 = 74MPa = F = 7000 = 74MPa BENDING BENDING STRESSSTRESS A A ππ(11)(11)22/4 /4 STRESS STRESS PROFILEPROFILE



TYPES of STRESS:TYPES of STRESS: σσ = My = = My = 7000x19 57000x19 5x5 5= 1045MPa x5 5= 1045MPa MOMENTMOMENTTYPES of STRESS:TYPES of STRESS: σσ = My = = My = 7000x19.57000x19.5x5.5= 1045MPa x5.5= 1045MPa

I I ππ(11)(11)44/64 /64 DIRECT DIRECT STRESS STRESS PROFILEPROFILE

YM M

PROFILEPROFILE

7kN7kNFF

X

Y

7kN7kN

XZ 7kN x 19.5mm 7kN x 19.5mm

Shear/TorsionShear/Torsion7kN7kN

σσ = F = 7000 = 74MPa = F = 7000 = 74MPa BENDING BENDING STRESSSTRESS

7%7%A A ππ(11)(11)22/4 /4

STRESS STRESS PROFILEPROFILE



TYPES of STRESS:TYPES of STRESS:TYPES of STRESS:TYPES of STRESS:7kN7kN

7kN7kN




1600STRESS XX

GRAPH GRAPH STARTSTART

GRAPH GRAPH ENDEND

1200

1400STRESS -XX- ENDEND

800

1000

400

600

0

200

-60 -40 -20 0 20 40 60




FF FF

QQMM

SIO

NSI

ON

ESSI

ON

ESSI

ON

TEN

STE

NS

CO

MPR

EC

OM

PRE

TensionTension CompressionCompression Shear/TorsionShear/Torsion BendingBending





PRINCIPAL STRESSES:PRINCIPAL STRESSES:PRINCIPAL STRESSES:PRINCIPAL STRESSES:

YY

σσyyyy

σσxyxy

σσxxxx

XZ XZ




YY

σσyyyyZEROZEROZEROZERO

σσxxxx

XZ

ZEROZERO

XZ




CRACKS WILL TEND CRACKS WILL TEND TO FORM NORMAL TOTO FORM NORMAL TOTO FORM NORMAL TO TO FORM NORMAL TO THE DIRECTION OF THE DIRECTION OF THE P1 STRESSTHE P1 STRESS

TENSION (P1)TENSION (P1)

COMPRESSION (P3)COMPRESSION (P3)




P3P3

P2P2

P1P1

P3P3

MOST MOST TENSILETENSILE

MOST MOST COMPRESSIVECOMPRESSIVE

P1 > P2 > P3P1 > P2 > P3SLIDE SLIDE -- 4949 --


PRINCIPAL STRESSES:PRINCIPAL STRESSES:PRINCIPAL STRESSES:PRINCIPAL STRESSES:PRINCIPAL STRESSES:PRINCIPAL STRESSES:PRINCIPAL STRESSES:PRINCIPAL STRESSES:

Y P1P1Y P1P1

P3P3P3P3

XZ NO SHEAR STRESS ON NO SHEAR STRESS ON XZ NO SHEAR STRESS ON NO SHEAR STRESS ON PRINCIPAL PLANES PRINCIPAL PLANES



FREEFREE--BODY DIAGRAMS:BODY DIAGRAMS:FREEFREE BODY DIAGRAMS:BODY DIAGRAMS:

Y7kN7kN7kN7kN

X

Y

7kN7kN7kN7kN


7kN7kN7kN7kN

CALCULATIONS REQUIRED:i) BENDING CALC (M=7kNx19.5mm)ii) DIRECT STRESS CALC (7kN)

CALCULATIONS REQUIRED:




FY F

X

Y

ZC

MF F

M - F x L

XZ

LMM - F x L

F

CCC

Free-body

F

i) BENDING CALC (M)ii) SHEAR STRESS CALC (F)

CALCULATIONS REQUIRED:

ii) SHEAR STRESS CALC (F)iii) DIRECT STRESS CALC (C)




TConcrete Block in vertical direction:

1226 25 T ( h f T 1226 25 125 ).. ..

2T

T

T T

mx = 1226.25 – T (therefore T = 1226.25 – 125 x ).. ..

R2T

2T mx..

T ..x

1962N

Mx..

2 1226.25N (125x9.81)

μR LOG in Y direction:

R=1962 cos(30) = 1699N96 N

(200x9.81)

LOG in X direction:

Mx = 2T – 1962 sin(30) – 849 5 > Mx = T – 490 5 – 424 75.. ..

Mx 2T 1962 sin(30) 849.5 … > …. Mx T 490.5 424.752 4



KARABINER FEA (open gate):KARABINER FEA (open gate):KARABINER FEA (open gate):KARABINER FEA (open gate):LOADING:LOADING:

7kN7kN 7kN7kN

FORCEFORCE QUANTIFIEDQUANTIFIED BY:BY:Y FORCE FORCE QUANTIFIEDQUANTIFIED BY:BY:


ii)ii) DIRECTIONDIRECTIONX

Y

Z ii)ii) DIRECTIONDIRECTION

iii)iii) POINT OF APPLICATIONPOINT OF APPLICATIONXZ



KARABINER FEA (open gate):KARABINER FEA (open gate):KARABINER FEA (open gate):KARABINER FEA (open gate):

7kN7kN39.83MPa39.83MPa

7kN7kN95.58MPa95.58MPa

44.99MPa44.99MPa

FORCEFORCE QUANTIFIEDQUANTIFIED BY:BY:Y FORCE FORCE QUANTIFIEDQUANTIFIED BY:BY:


ii)ii) DIRECTIONDIRECTIONX

Y

ZFxFy ii)ii) DIRECTIONDIRECTION

iii)iii) POINT OF APPLICATIONPOINT OF APPLICATIONXZ

Mz



KARABINER FEA (open gate):KARABINER FEA (open gate):KARABINER FEA (open gate):KARABINER FEA (open gate):CONSTRAINTS?CONSTRAINTS?

7kN7kN 7kN7kN

Total X load = -0.23463168T t l Y l d 0 72929234Y

Total load balance w.r.t. origin

Total Y load = -0.72929234Total Z load = 0.32684966E-11

Total X moment = 0.19089799E-11X

Y

Z Total Y moment = 0.48650861E-10Total Z moment = 9.5877061

XZ



KARABINER FEA (open gate):KARABINER FEA (open gate):KARABINER FEA (open gate):KARABINER FEA (open gate):WITNESS MARK TO WITNESS MARK TO APPLIED PRESSURESAPPLIED PRESSURES



KARABINER FEA (open gate):KARABINER FEA (open gate):KARABINER FEA (open gate):KARABINER FEA (open gate):



CONTENTS:CONTENTS:••INTRODUCTIONINTRODUCTION

••PLANET EARTHPLANET EARTH

CONTENTS:CONTENTS:






EXAMPLE KARABINER (O G )EXAMPLE KARABINER (O G )••EXAMPLE: KARABINER (Open Gate)EXAMPLE: KARABINER (Open Gate)


••EXAMPLE: KARABINER (Closed Gate)EXAMPLE: KARABINER (Closed Gate)EXAMPLE: KARABINER (Closed Gate)EXAMPLE: KARABINER (Closed Gate)





DETERMINATE or INDETERMINATE?DETERMINATE or INDETERMINATE?DETERMINATE or INDETERMINATE?DETERMINATE or INDETERMINATE?




7kN7kN 7kN7kN

AA AA

von Mises stressvon Mises stressSLIDE SLIDE -- 6363 --



21kN21kN21kN21kN22 AA

AABBBB

21kN21kN22

BB

Cartesian XX stressCartesian XX stressSLIDE SLIDE -- 6464 --




CONTENTS:CONTENTS:













KARABINER FEA: (closedKARABINER FEA: (closed--gate)gate)KARABINER FEA: (closedKARABINER FEA: (closed gate)gate)

LOADING:LOADING:

21kN21kN 21kN21kN

21kN21kN22

21kN21kN2222




CONSTRAINTS:CONSTRAINTS:

TX TX TY TY TY TY TZ TZ RX RX RY RY RZRZ




P1 RESULTSP1 RESULTSSLIDE SLIDE -- 6868 --



P1 RESULTSP1 RESULTSSLIDE SLIDE -- 6969 --




CONTENTS:CONTENTS:






EXAMPLE KARABINER (O G )EXAMPLE KARABINER (O G )••EXAMPLE: KARABINER (Open Gate)EXAMPLE: KARABINER (Open Gate)


••EXAMPLE: KARABINER (Closed Gate)EXAMPLE: KARABINER (Closed Gate)EXAMPLE: KARABINER (Closed Gate)EXAMPLE: KARABINER (Closed Gate)





MINIMAL CONSTRAINT METHODS IN FEA:MINIMAL CONSTRAINT METHODS IN FEA:MINIMAL CONSTRAINT METHODS IN FEA:MINIMAL CONSTRAINT METHODS IN FEA:




3-2-1

Minimum 3-2-1 Constraint

1500N 1500N

Total X load = -0.45561796E-04Total Y load = -0.21314001E-04Total Z load = 0.00000000E+00

Total X moment = 0.14775466E-04Total Y moment = 0.11048210E-03Total Z moment = -0.81574873E-02



MINIMAL CONSTRAINT METHODS IN FEA:MINIMAL CONSTRAINT METHODS IN FEA:MINIMAL CONSTRAINT METHODS IN FEA:MINIMAL CONSTRAINT METHODS IN FEA:10kN

10kN

2

1

10kN10kN

3

3-2-1Balanced Loading and Minimum Constraint in 3D – Crank




1133

11

3-2-122

Balanced Loading and Minimum Constraint in 3D – Full model of Karabiner




22 1122 11

3-2-1Balanced Loading and Minimum Constraint in 3D – Half model of Karabiner




No 1 plane of 2 planes of 3 planes of No Symmetry

1 plane of symmetry

2 planes of symmetry

3 planes of symmetry

Balanced Balanced Balanced Balanced Loading Loading Loading Loading

3 2 1 3 2 1 3 2 1 3 2 13-2-1 3-2-1 3-2-1 3-2-1(2D Plane Stress/Strain) (2D Axi-symmetric)

6 global freedoms

3 global freedoms

1 global freedom

0 global freedoms




••Achieve a modernAchieve a modern--day balance between hand calcs and FEAday balance between hand calcs and FEAAims:Aims:

••Provide a number of “mustProvide a number of “must--have” formulas for stress analysishave” formulas for stress analysis

••Provide a summary of the technique of FreeProvide a summary of the technique of Free--Body DiagramsBody Diagrams

••Practical advice for best use of FEA for realistic solutionsPractical advice for best use of FEA for realistic solutions

••Constraints that gives minimal support & worstConstraints that gives minimal support & worst--case stressescase stresses



A NAFEMS Webinar organised by Matthew Ladzinski of A NAFEMS Webinar organised by Matthew Ladzinski of NAFEMS Limited (North America).NAFEMS Limited (North America).

Matthew Ladzinski@NAFEMS OrgMatthew Ladzinski@NAFEMS [email protected]@NAFEMS.Org

Presented by Bob Johnson BSc MSc NRA MIMechE CEng Presented by Bob Johnson BSc MSc NRA MIMechE CEng DAMT Limited, UKDAMT Limited, UKDAMT Limited, UKDAMT Limited, UK

[email protected]@damt.co.uk


THE INTERNATIONAL ASSOCIATIONTHE INTERNATIONAL ASSOCIATIONFOR THE ENGINEERING ANALYSIS FOR THE ENGINEERING ANALYSIS

COMMUNITYCOMMUNITY

Q&A SessionQ&A SessionUsing the Q&A tool, please submit any Using the Q&A tool, please submit any questions you may have for our panel.questions you may have for our panel.questions you may have for our panel.questions you may have for our panel.

THE INTERNATIONAL ASSOCIATIONTHE INTERNATIONAL ASSOCIATIONFOR THE ENGINEERING ANALYSIS FOR THE ENGINEERING ANALYSIS

COMMUNITYCOMMUNITY

Thank you!Thank you!

COMMUNITYCOMMUNITY

Thank you!Thank you!

[email protected]@nafems.org

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