structural optimization and stress analysis with hypershape/catia

WELCOME TO THE NETWORK OF COMPETENCE

OptiStruct in CATIA V5OptiStruct in CATIA V5OptiStruct in CATIA V5OptiStruct in CATIA V5

Isabel Braun Isabel Braun Isabel Braun Isabel Braun ---- IndustrieHansa Stuttgart IndustrieHansa Stuttgart IndustrieHansa Stuttgart IndustrieHansa Stuttgart –––– 28 October 201028 October 201028 October 201028 October 2010

Structural Optimization and Stress Analysis with Structural Optimization and Stress Analysis with Structural Optimization and Stress Analysis with Structural Optimization and Stress Analysis with

HyperShape/CATIA in the Automotive FieldHyperShape/CATIA in the Automotive FieldHyperShape/CATIA in the Automotive FieldHyperShape/CATIA in the Automotive Field

Structural Optimization and Stress Analysis with

HyperShape/CATIA in the Automotive Field

Isabel Braun, IndustrieHansa Stuttgart, 28 October 2010 2

CONTENTSCONTENTSCONTENTSCONTENTS

� IndustrieHansaIndustrieHansaIndustrieHansaIndustrieHansa –––– Consulting & EngineeringConsulting & EngineeringConsulting & EngineeringConsulting & Engineering

� HyperShape/CATIAHyperShape/CATIAHyperShape/CATIAHyperShape/CATIA

� Topology optimization armrest substructureTopology optimization armrest substructureTopology optimization armrest substructureTopology optimization armrest substructure

� Topology optimization gear bracketTopology optimization gear bracketTopology optimization gear bracketTopology optimization gear bracket

� SummarySummarySummarySummary




IndustrieHansaIndustrieHansaIndustrieHansaIndustrieHansa –––– Consulting & EngineeringConsulting & EngineeringConsulting & EngineeringConsulting & Engineering

Founded in 1977Founded in 1977

Over 900 employeesOver 900 employees

IBA – In-house training academyIBA – In-house training academy

Certified to ISO 9001 & EN 9100Certified to ISO 9001 & EN 9100

Close to our main customersClose to our main customersClose to our main customers

About usAbout usAbout usAbout us





Industrial EngineeringIndustrial Engineering

Digital EngineeringDigital Engineering

Automotive

Aviation

Energy

From idea

Toproduction

Engin

eering

Tra

inin

g

Consultin

g

Technical DocumentationTechnical Documentation

Our servicesOur servicesOur servicesOur services





Tier 1

OEM

22 years22 years

25 years25 years

12 years12 years

11 years11 years

14 years14 years

Our customersOur customersOur customersOur customers




HyperShape/CATIAHyperShape/CATIAHyperShape/CATIAHyperShape/CATIA

What can HyperShape/CATIA do?What can HyperShape/CATIA do?What can HyperShape/CATIA do?What can HyperShape/CATIA do?

HyperShape/CATIA is completely integrated into the CATIA V5 environment

and covers the following optimization disciplines.

Optimization disciplines of HyperShape/CATIAOptimization disciplines of HyperShape/CATIAOptimization disciplines of HyperShape/CATIAOptimization disciplines of HyperShape/CATIA

Gauge optimizationProfile wall thickness, sheet thickness

Topology optimization

Global optimization, removing and allocating material

Topography optimizationFinding the best arrangement of beading in blank sheets

Free Shape optimization

Local optimization, e.g. smoothing out stress peaks





Topology optimizationTopology optimizationTopology optimizationTopology optimization

Based on a given available space (Design space) the ideal material allocation

for the given boundary conditions is determined. Material is removed and

allocated to reach the optimal target.

�� WeightWeightWeightWeight

�� StiffnessStiffnessStiffnessStiffness

�� EigenfrequencyEigenfrequencyEigenfrequencyEigenfrequency

�� StressStressStressStress

�� DisplacementDisplacementDisplacementDisplacement

Man-made constructions are usually developed in a target-oriented manner.

Natural structures, however, are developed by trial and error.

This method of trial and error can also be employed for optimizing technical

products. It’s better to use software for trial and error instead of wasting an

engineer’s time.





Conventional design processConventional design processConventional design processConventional design process Enhanced design processEnhanced design processEnhanced design processEnhanced design process

Comparison of conventional and enhanced design processComparison of conventional and enhanced design processComparison of conventional and enhanced design processComparison of conventional and enhanced design process

Design spaceDesign spaceDesign spaceDesign space

Topology optimizationTopology optimizationTopology optimizationTopology optimization

CAD conceptCAD conceptCAD conceptCAD concept

FEFEFEFE----AnalysisAnalysisAnalysisAnalysis

End DesignEnd DesignEnd DesignEnd DesignChange itChange itChange itChange it

OKOKOKOK NOKNOKNOKNOK

CAD conceptCAD conceptCAD conceptCAD concept

FEFEFEFE----AnalysisAnalysisAnalysisAnalysis

Detail optimizationDetail optimizationDetail optimizationDetail optimizationStart againStart againStart againStart again

End DesignEnd DesignEnd DesignEnd Design

OKOKOKOK NOKNOKNOKNOK




Topology optimization Topology optimization Topology optimization Topology optimization ---- Armrest substructureArmrest substructureArmrest substructureArmrest substructure

Armrest substructure Armrest substructure Armrest substructure Armrest substructure –––– CAD model already existsCAD model already existsCAD model already existsCAD model already exists

� Armrest substructure does not show the required strength in the test.

� Structural strength of existing part needs to be optimized.

� Maximum available space defined by exterior geometry, ribbing (core

removal) may be altered.

� Three static load cases (misuse cases) have to be considered.

� Armrest substructure will be manufactured as an aluminum die cast

component.





Load critical areasLoad critical areasLoad critical areasLoad critical areas

crossover to the platform

pivot bearing

PlatformPlatformPlatformPlatform

thickness 12 mm

Pivot bearingPivot bearingPivot bearingPivot bearing

thickness 22 mm

Initial situationInitial situationInitial situationInitial situation

The illustration shows the CAD model before optimization. Alterations may

only be carried out on the ribbing.




F-y=400 NF+y=400 NF+z=400 N

20

0 m

m Virtual lever arm

Force

application

Virtual Bolt

Load case 1Load case 1Load case 1Load case 1 Load case 2Load case 2Load case 2Load case 2 Load case 3Load case 3Load case 3Load case 3

Virtual stopper

Virtual washers

(bilateral)

33

1 m

m

40

0 m

m

Load casesLoad casesLoad casesLoad cases






σσσσVVVV ≈≈≈≈ 150 150 150 150 MPaMPaMPaMPa

FEFEFEFE----Analysis CAD model / Platform areaAnalysis CAD model / Platform areaAnalysis CAD model / Platform areaAnalysis CAD model / Platform area

In load case 1, von Mises stress of up to 350 MPa appears inside the ribbing.

Without core removal, the FE-Analysis shows that Rp0,2 is exceeded over a

large area. In the given available space no improvement can be expected by

removing and allocating material.

σσσσVVVV ≈≈≈≈ 350 MPa350 MPa350 MPa350 MPa

Platform before

optimization with

core removal

Platform before

optimization without

core removal

>>>>




Manual calculation CAD model / Platform without core removalManual calculation CAD model / Platform without core removalManual calculation CAD model / Platform without core removalManual calculation CAD model / Platform without core removal

Topology optimization Armrest substructureTopology optimization Armrest substructureTopology optimization Armrest substructureTopology optimization Armrest substructure

FFFF+z+z+z+z=400 N=400 N=400 N=400 Nl =

33

1 m

m

l =

33

1 m

m

FFFF+z+z+z+z=400 N=400 N=400 N=400 N

38

11

,8

Manual calculationManual calculationManual calculationManual calculationσb = Mb / Wb (1)

Mb = F+z * l (2)

Wb = Iy / e (3)

Iy = b * h³ / 12 (4)

σb: Bending stress

Mb: Bending moment

Wb: Section modulus

Iy: Area moment of inertia

from (2)

Mb = Force * lever arm =

= F+z * l = 400 N * 331 mm =

= 132.400 Nmm

from (4)

Iy = b * h³ / 12 =

= 38 mm * (11,8 mm)³ / 12 =

= 5203 mm4

from (3)

Wb = Iy / e = 5203 mm4 / 5,9 mm =

= 882 mm³

from (1)

σb = Mb / Wb =

= 132.400 Nmm / 882 mm³ =

= = = = σσσσbbbb =150 MPa=150 MPa=150 MPa=150 MPa

y

FFFF+z+z+z+z=400 N=400 N=400 N=400 N

B e

a m

b

e n

d I n

gB

e a

m b

e n

d I n

gB

e a

m b

e n

d I n

gB

e a

m b

e n

d I n

g

Yiel

d st

reng

th re

ache

d in

load

cas

e 1

even

with

sol

id m

ater

ial

Yiel

d st

reng

th re

ache

d in

load

cas

e 1

even

with

sol

id m

ater

ial

Yiel

d st

reng

th re

ache

d in

load

cas

e 1

even

with

sol

id m

ater

ial

Yiel

d st

reng

th re

ache

d in

load

cas

e 1

even

with

sol

id m

ater

ial

model

simplification

model

simplification

cross section

solid material

l =

33

1 m

m





Pivot bearing before

optimization with

core removal

Pivot bearing before

optimization without

core removal

>>>>

FEFEFEFE----Analysis CAD model / Pivot bearing areaAnalysis CAD model / Pivot bearing areaAnalysis CAD model / Pivot bearing areaAnalysis CAD model / Pivot bearing area

Without core removal, the FE-Analysis for load case 2 and 3 of the pivot

bearing area shows that Rp0,2 is only reached at certain local points. Therefore,

a possible approach is to develop a new ribbing structure using topology

optimization.

σσσσVVVV ≈≈≈≈ 150 150 150 150 MPaMPaMPaMPa

σσσσVVVV ≈≈≈≈ 220 MPa220 MPa220 MPa220 MPa






3 static load cases

Boundary conditionsBoundary conditionsBoundary conditionsBoundary conditions

Pivot bearing

Stopper, washers as

virtual elements

Material dataMaterial dataMaterial dataMaterial data

AlSi9Cu3 (Fe)

Density: 2,75 g/cm³

Young modulus: 75 GPa

Poisson’s number: 0,34

MeshingMeshingMeshingMeshing

Linear tetrahedron

Optimization targetsOptimization targetsOptimization targetsOptimization targets

Volume reduction to 30 percent

Maximization of stiffness


Manufacturing constraintsManufacturing constraintsManufacturing constraintsManufacturing constraints

Draw direction

Minimum wall thickness

Non-design space

Definition of the topology optimizationDefinition of the topology optimizationDefinition of the topology optimizationDefinition of the topology optimization

Constraints, loads and optimization goals

Draw direction -y

Draw direction +z

Protected areas

Optimization toolOptimization toolOptimization toolOptimization tool

HyperShape/CATIA





TensionTensionTensionTension----/Compression line/Compression line/Compression line/Compression line

To cope with the high bending moment from the relevant load cases,

HyperShape/CATIA generates a distinct, continuous tension-/compression line

with a high area moment of inertia (� section modulus).

Before optimizationBefore optimizationBefore optimizationBefore optimization

Arbitrary ribbing

After optimizationAfter optimizationAfter optimizationAfter optimization

Distinct, continuous

tension-/compression line

Tension-/

compression line

FFFF FFFF





Realization of the

design proposal,

recalculation with

CATIA-FEM

Highly stressed

areas in the

non-optimized

model

Much less

stress in the

solid model

Result of the structure

optimization with

HyperShape/CATIA

Reducing stress with structure optimizationReducing stress with structure optimizationReducing stress with structure optimizationReducing stress with structure optimization

>>>>

>>>>

Str

ess

Str

ess

Str

ess

Str

ess

20%20%20%20%

mass

mass

mass

mass

1%1%1%1%





ConclusionConclusionConclusionConclusion

� Platform does not show potential for structure optimization, fails even with

solid material (without core removal) in load case 1.

� Pivot bearing shows high stress in non-optimized CAD model, with solid

material (without core removal) 150 MPa is reached only locally.

� The optimized structure is clearly better than the non-optimized structure,

but also exceeds the yield strength.

�When there is no material, not even a high-end optimization tool like

OptiStruct can work magic. Without enough design space no rational

structure optimization is possible.

Possible further stepsPossible further stepsPossible further stepsPossible further steps

� Increase of the design space parameters (thickness of pivot bearing and

platform) and renewed structure optimization of this new design space.

�Usage of a material with higher yield strength.




Gear bracket Gear bracket Gear bracket Gear bracket –––– CAD model does not exist yetCAD model does not exist yetCAD model does not exist yetCAD model does not exist yet

Available design space with interfering geometry

Topology optimization Topology optimization Topology optimization Topology optimization ---- Gear bracketGear bracketGear bracketGear bracket

Available spaceAvailable spaceAvailable spaceAvailable space

for gear bracketfor gear bracketfor gear bracketfor gear bracket

Body shellBody shellBody shellBody shell

Side shaftSide shaftSide shaftSide shaft

Gear mountGear mountGear mountGear mount

Gear housingGear housingGear housingGear housing

GeneratorGeneratorGeneratorGeneratorSupport armSupport armSupport armSupport arm





Force application via gear bracket

and support arm to body shell

Attachment to

the Gear housing

Boundary conditions and loads Boundary conditions and loads Boundary conditions and loads Boundary conditions and loads

Attachment points and force application







6 static load cases

1 frequency load case

Bolt tightening

Boundary conditionsBoundary conditionsBoundary conditionsBoundary conditions

Gear housing attachment

points are clamped

Material dataMaterial dataMaterial dataMaterial data

EN AC-Al Si8Cu3

Density: 2,75 g/cm³

Young modulus: 75 GPa

Poisson’s number: 0,34MeshingMeshingMeshingMeshing

linear tetrahedron

Optimization targetsOptimization targetsOptimization targetsOptimization targets

Volume reduction to 30 percent

Maximization of stiffness

Raising of the first three eigenfrequencies


Manufacturing constraintsManufacturing constraintsManufacturing constraintsManufacturing constraints

Draw direction

Minimum wall thickness

Definition of the topology optimizationDefinition of the topology optimizationDefinition of the topology optimizationDefinition of the topology optimization

3

2

1

± 19 kN

± 4 kN

± 27 kN

Force / ModeForce / ModeForce / ModeForce / Mode

1

2

3

2

2

2

WeightingWeightingWeightingWeighting

Frequency load case

Static load case Fz

Static load case Fy

Static load case Fx

Load caseLoad caseLoad caseLoad case





CAD CAD CAD CAD Modeling design space

CAECAECAECAE Meshing design space,

apply boundary conditions and loads

CADCADCADCAD Generating a part suitable for manufacture

based on the design suggestion

CAE CAE CAE CAE Remove and allocate material

CAECAECAECAE Recalculation of the CAD model with CATIA FEM

and local optimization if necessary

�

�

�

�

�

Topology optimization workflowTopology optimization workflowTopology optimization workflowTopology optimization workflow




SummarySummarySummarySummary

� HyperShape/CATIA is an efficient tool for concept design and optimization

within the CATIA V5 environment.

� Limits of optimization, e.g. Armrest substructure.

� Load bearing capacity and optimal weight found before the first CAD

concept, e.g. Gear bracket.

� Reducing trial & error during development.

� Early application in the development process enables target-orientated

construction.




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structural optimization and stress analysis with hypershape/catia

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