Draping Simulation – The key to low cost high performance net- shape parts?

5th

International CFK-Valley Stade ConventionJune 7th, 2011

Dipl.-Ing. Andreas KnoteInstitute of Composite Structures and Adaptive Systems, Department Composite Design

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What are draping and draping simulation?

DrapingApplication of planar material onto a curved surface. To adapt to the

contour the material needs to be stretched and sheared.

Shearing

Warp

Weft

Draping simulationPrediction of material behavior during draping with the help of a model.

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Presentation overview

Introduction to draping simulation

Sharing results of draping simulation study

Overview of software benchmark

Tool chain implementation of draping simulation

Comparison of theory and practice

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Why do we need powerful draping simulation?

Production of composite parts…

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Why do we need powerful draping simulation?

…requires highest precision on the factory floorProduction of composite parts…

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Why do we need powerful draping simulation?

Actual geometry

Actual fiber paths

Desired geometry

Desired fiber paths

…requires highest precision on the factory floorProduction of composite parts…

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Why do we need powerful draping simulation?

Actual geometry

Actual fiber paths

Desired geometry

Desired fiber paths

Draping simulation supports manufacturing and improves part quality

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Motivation

Draping simulationShows producibility

quickly and with lowest effortDelivers all relevant manufacturing informationCalculates fiber orientations after draping

Thus precise preformingReduces labor in manufacturingSpeeds up processesSaves waste of expensive material

Draping simulation strongly influences successive steps in the process chain.

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1 2 3 4 5 6

Number of parameters

Num

ber o

f pos

sibl

e si

mul

atio

n re

sults

Can the user cope with draping simulation?

Available input parametersPart geometryAlgorithmMesh

size/Fiber Spacing FactorOrientation

(0°, ±45°, 90°)Seed

point coordinateSeed

curve

configuration

90°45° 0%

33%50%

75%100%

33%50%

x0.000 possibilitiesfor doing it right

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Methodology to evaluate performance of draping simulationPre-Processing

3D-Model

Draping-parameters

Run simulation

Flat pattern

Benchmark

Shear,Errors

xy

R

45°

Trying outof parameters

±±±±±

Pre-Processing

3D-Model

Benchmark

Draping-parameters

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Methodology to evaluate performance of draping simulation

Run simulation VBA+Macro

CPD/AFM/

FS/LTFlat pattern

Pre-Processing

3D-Model

Draping-parameters

Run simulation

Flat pattern

Benchmark

xy

R

45°

Pre-Processing

3D-Model

Excel,CATIA V5

Benchmark

MatLabArea,

Circumference,Angle

Draping-parameters

Systematic analysis instead of trying out

Systematicvariation of model

and parameters

±

Systematicanalysis

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Different part geometries with increasing complexityL-bracketL-frameC-frameB-pillar

Increasing complexity for practically oriented results

Methodology to evaluate performance of draping simulation

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Influence of mesh size

Software2

2mmmesh size

10mmmesh size

Different software deliver different results even for simple geometries

Software1 & 3

11mmmesh size

A2

=2490mm² A2

= ∞ A2

=9707mm²

A1

=9958mm²

A3

=9955mm²

A1

=9754mm²

A3

=9955mm²

A1

=9829mm²

A3

=9955mm²

Flat pattern area of a simple L-bracket:ARef =9957mm²

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Influence of mesh size

Dassault CPD & Simulayt

AFM Vistagy

FiberSIM

& Anaglyph

LT

-5

-4

-3

-2

-1

00 2 4 6 8 10

Mesh size [mm]

Are

a de

viat

ion

[%]_

Dassault CPD Simulayt AFM

CPD: Convergence at smaller mesh sizeAFM: Flat patterns constantly precise

FiberSIM: Convergence at smaller mesh sizeLT: Convergence at larger mesh size

x10-3

0

0,5

1

1,5

2

2,5

3

0,1 0,5 1 2 3 5

Fiber Spacing FactorFS

are

a de

viat

ion

[%]__

0

0,5

1

1,5

2

2,5

LT a

rea

devi

atio

n [%

]_

Vistagy FiberSIM Anaglyph LT

x10-3

Flat pattern precision of an L-bracket at different mesh sizes

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Influence of seed point position

Seed point mode of action:Starting point of meshing algorithmRepresents the fixation point in the real drapingStrongly influences draping result

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Influence of seed point positionWhere to place the seed point?

Seed

Point

Cut the meshX

X

X

X

X

Par

t edg

e

Defect

mesh Shear

Correct

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Software comparison results

Four draping simulation software were evaluated:Composite Part Design (CPD), a Module of Catia (V5R18 SP6)Simulayt AFM 1.0nVistagy FiberSIM 2009Anaglyph Laminate Tools 3.4

CATIACPD

Simulayt AFM (+CPD)

Vistagy FiberSIM

Anaglyph Laminate

Tools

Robustness o + +++ ++

Precision o ++ +++ ++

Ply contours and surface derivation ++ ++ +++ o

Feature management (Ramps, Cores...) + ++ +++ o

Fiber orientation steering o ++ + +++

CAD-user interface integration +++ +++ + o

FE-Interface o + ++ +++

Other interfaces + ++ +++ o

Result of DLR study and independent expert user questionnaire (60 attendants)

Perf

or-

man

ceU

ser o

ptio

nsan

d in

put

Inte

rfac

es

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Implementation in the tool chain

Draping simulation plays an essential role in the tool chain

Aer

odyn

amic

s

Load

s

Global FE

Stress

Quality Control

Material & Process

Cer

tific

atio

n

Mater

ial P

rope

rties

Design

Overall DesignManufacturingEngineering

User know-how

VirtualCompositePlatform

α

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Draping Simulation – The key to low cost high performance net-shape parts?

Draping simulation can be the key if correctly applied:

Reduced discarded excess material

Reduced manual rework

Full tool chain integration leads to design as build

Reduce weight by utilizing the simulated fiber angles in FE

Increase of automation with precise flat patterns

High quality flat patterns the first time

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Contact

DLR German Aerospace CenterInstitute of Composite Structures and Adaptive SystemsDepartment Composite Design

Dipl.-Ing. Andreas KnoteLilienthalplatz

7D-38108 Braunschweig

+49 531 295 3289andreas.knote@dlr.de

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From simulation to experiment

Going all the way from theory to practice

Video: DLR, Institute FK