Section 5 Curing, Draping, and CAD Interface

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Composites Technology Day, February 2012

Copyright 2012 MSC.Software Corporation



Section 5

Curing, Draping, and CAD Interface

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Curing and Shrinkage

during

Manufacturing

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MSC Composite Curing Capability

• Cure-induced heating and curing shrinkage

– Thermal heat generation due to curing

– Shrinkage strains associated with curing

– Causes distortion and residual stress in parts

– Prediction is critical for predicting final shape

• Coupled thermo-mechanical analysis

– Critical capability for process development

– Available for solid and shell elements

– Marc has this unique capability in the industry

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• Cure analysis is done to evaluate the degree of cure and curing reaction heat flux

• Cure rate evaluation is based on temperature and curing kinetics models

• Curing heat flux term due to the change of degree of cure is added to RHS of heat transfer pass

• An iterative time integration scheme has been developed so that the degree of cure is accurately calculated for the heat transfer pass

• Fraction of cure and temperatures are transferred to Mechanical pass

• Volumetric Resin Shrinkage is incorporated in the Mechanical pass

• Degree of Shrinkage is defined as function of degree of cure and

temperature

• Curing Shrinkage Strain Components are calculated based on the

volumetric resin shrinkage

• Post processing data includes degree of cure, curing heat flux, resin

shrinkage strains

• User subroutine support for curing kinetics and curing shrinkage

models

Thermal-Cure-Mechanical Analysis

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Start of Thermal Cycle

(Cure pass)

Mechanical

pass

Thermal pass End of Thermal Cycle

Cure rate

Reaction Heat

flux

Converged?

Yes

No Degree of

cure

Temperatures

Thermal-Cure-Mechanical Analysis Flow

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– Load case 1 ---- Heating and Forming • Boundary conditions:

– Pressure

– Vacuum

– Temperature

Pressure Vacuum Temperature

Laminate Forming Example

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– Load case 2 ---- Base movement • Boundary conditions:

– Pressure

– Vacuum

– Temperature

– Base move Base

Dx=0.002

Dy=0.002

Dx

Dy


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– Load case 3 ---- Spring-back • Boundary conditions:

– Pressure

– Vacuum

– Temperature

– Release_x

– Release_y

– Fix_z

Release_x Release_y


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History Plot:

Degree of Cure & Degree of Cure Shrinkage

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Shrinkage Strain

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• A. With Curing

• B. Without Curing

A

B

Residual Stresses (Before Springback)

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• A. With Curing

• B. Without Curing

A B

Residual Stresses (After Springback)

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0°/90°, +/- 45° Orthotropic Layup

Case Study : Sikorsky S-92 Helicopter

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Case Study

.345” predicted

Springback

.35” actual

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Draping and CAD Interface

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Laminate Modeler

• An add-on to Patran

• Process simulation

– Ply based approach

– Ply draping

• Ply management allows for

rapid modifications during

model development

• Account for thickness and

fiber direction changes in

draped plies

• Model manufactured

component accurately

including splits/darts

• Direct interface to CAD

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Why Laminate Modeler?

• Real structures aren’t flat

plates …

– Complex curvature requires

draping

• Manufacturing: Flat

pattern development

• Analysis: Accurate

orientation information

– Complex layups require ply

management

• Countless plies

• Ply drop-off

• Element CID misalignment

• Results in countless

PCOMPs and changes

become … costly …

Fiber orientations

Ply E

Ply D

Ply C

Ply B

Ply A

Layer 5

Layer 4

Layer 3

Layer 2

Layer 1

PCOMP 1 PCOMP 2 PCOMP 3

PC

OM

P L

ayers

Glo

bal P

lies

PCOMP 4

Elements

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Ply Draping Simulation Example

• Ply layup on hemisphere improved with splits

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Direct CAD Interface - FiberSIM

Layup info

FiberSIM

CATIA

Patran/LM

Optimization

Analysis

PCOMPs

Nastran

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Interface to FiberSIM

• Directly access layup data from

FiberSIM

– FiberSIM plies and layup files are

imported and mapped onto analysis

mesh

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Concluding Remarks

• MSC has a strong composites solution meeting

your end-to-end product development process

simulation needs

• Nastran/Patran/Laminate Modeler supports this

composites solution workflow

• As required, Marc can easily be incorporated

into this workflow to provide additional

capabilities

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Source: Frank Doerner, MSC 2011 User’s Conference Keynote Speaker

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Thank You!

Documents

Section 5 Curing, Draping, and CAD Interface