TEchnologies for Carbon fibre reinforcedmodular Automotive Body Structures2000-2004

alusuisse airex composites

VOLKSWAGEN AG

Volvo Car Corporation

ICMA

This project is supported by the European Commission

More information available at: Willems & van den WildenbergTelephone +31.70.352.33.61Email: tecabs@wnw.nl

KU Leuven

SAERTEXWagener GmbH & Co.KG

®

TECABS

TEchnologies for Carbon fibre reinforced modular Automotive Body Structures

Summary

Ø Development of technologies and methods enabling the realisation of acomposite Body in White (BIW) concept in 50 units/day series ofcommercial cars and a 50% weight reduction based on the use of low costheavy tow carbon fibre textiles, finally resulting in a reduction of CO2emission.

Ø By using complex shaped multi-functional parts and smart joiningtechnologies, the number of parts could be reduced to 30% (present 200+).It is assumed that a reduction of parts which results in less tooling andjoining equipment makes a composite BIW concept cost effective even ifthe manufacturing costs per single part are still expected to be higher.

Ø Total project budget: 5.2 million and is supported by EC under the R&Dresearch program Growth.

Ø Project started in April 2000 and ends in April 2004Ø Large consortium of automotive car manufacturers, suppliers and research

institutes in Europe to investigate technologies enabling the developmentof a lightweight Carbon Fibre Reinforced Plastics(CFRP) BIW.

TEchnologies for Carbon fibre reinforced modular Automotive Body Structures

Project objectives

Ø Development of technologies and methods enabling the realisation of acomposite Body in White concept in 50 units/day series of commercialcars and a 50% weight reduction based on the use of low cost heavytow carbon fibre textiles, using:

§ high speed low cost RTM processes and cost effective / high speedpreform and resin technologies

§ simulation technologies of static / crash behaviour and economic &environmental performance

§ modular methodology to translate performance requirements into feasiblepart concepts using these new technologies

Ø The project results in each of these exploitable technologies andvalidates the integrated achievements by means of testing a full-scalemulti-functional floor pan as a demonstrator part under variousconditions.

TEchnologies for Carbon fibre reinforced modular Automotive Body Structures

Results 2000 - 2002

Ø Conceptual design of composite Body-In-White completed

Ø Detailed design of multifunctional composite floor pan completed

Ø Elaboration of LCI methodology based on input/output data of energy andCO2 emission completed

Ø Development of part performance simulation tools (CAE)

Ø Development of crash concepts & simulation tools

Ø Development of preforming technologies & new materials

Ø Development of improved RTM injection technologies

Results realised during the first 30 months of the project: April ‘00 - Oct. ‘02

TEchnologies for Carbon fibre reinforced modular Automotive Body Structures

Ø Elaboration of package and structural requirements of the Body in White

Ø Composite BIW concept and detailed design of floor pan completed

Ø Split up of floor pan into several „sub-preforms“ sandwich & monolithic

Ø FEA calculations have been performed using NASTRAN based on laminatemodelling; PUCK’s 2D-failure criterion implemented in PATRAN

Ø Development and design of joining technologies (bonding & load introductionconcepts); selection, FEA and testing of bolted and bonded CFRP specimen

Design of composite Body in White (BIW)

Steel BIW

Weight 203 kg

Number of Parts 200

Static Stiffness 22.9 min

Dyn. Tors. Stiffness 40 Hz

Dyn. Bend. Stiffness 43 Hz

Target

50%=102 kg

30%=60

22.9 min

100%

100%

BIW 24 months

79 + x kg*

64 + x*

25.5 min

71 Hz

61 Hz

* not all functions integrated

BIW 18 months

80 + x kg*

45 + x*

30.7 min

68 Hz

60 Hz

Results 2000 - 2002

TEchnologies for Carbon fibre reinforced modular Automotive Body Structures

Ø Geometry: Development of a universal description of yarnsinside a textile, mathematical models and software packageWisetex.

Ø Large Strain Deformation (draping): Geometrydescription + load-deformation curves (except for NCF)

Ø Mechanical Performance: The stiffness matrix can be built(except for deformed reinforcement).

Ø Permeability: Mathematical formulation of models forpermeability of textile reinforcements based on LatticeBoltzmann approach. Development of software packageFlowtex (not for deformed non-crimp fabric unit cell).Developments of a theoretical method to calculate bothsaturated and average permeability tensors using fluidmechanics software Fluent. Link established with thegeometrical description from Wisetex.

Ø Cost Prediction tool: Based on industrial data costprediction tool developed and and under validation now.

Ø CAE TOOLS: Crash simulation software (PAM-CRASH)can read/use draping results (PAM-FORM). RTMsimulation software (PAM-RTM) can read/use drapingresults (PAM-FORM).

Development of part performance simulation tools (CAE)

Results 2000 - 2002

Woven fabrics geometryrepresentation

Resin velocity inside a unit cell ofa quadri-axial fabrics

TEchnologies for Carbon fibre reinforced modular Automotive Body Structures

Development of crash concepts and simulation tools

Results 2000 - 2002

Ø Composite crash analysis on modelling delamination oflarge-scale complex structures, braided samples & trialswith NCF

Ø Physical crash testing of tubes, braided and NCF withvarious fibre lay up

Ø Implementation of crash tests and new models inPAMCRASH software to study ply delamination and anew technique for crash prediction behaviour of axialcrushing of composite sections.

Ø 1st design of frontal crash parts and structure based onhigh-speed deformation demands, using ABACUS andnew models in PAMCRASH

3D crushing/fracturingzone

Potentialcrushing,buckling,delamination,transversecracking, etc.zone

Fractureinitiation

Fracturepropagation

TEchnologies for Carbon fibre reinforced modular Automotive Body Structures

Ø Worldwide screening of low cost heavy tow carbon fibres from 24k to 80k.

Ø Selection of a thermoset epoxy resin system, and a potential toughener.

Ø Characterisation of mechanical properties, drapability and permeability ofnon-crimp fabrics, braids and their composites.

Ø Screening of heavy tow carbon fibre yarns applicable for thermoplastic resinRTM, and manufacturing of dedicated fabrics.

Ø Development of textile processes for the production of carbon fibre fabrics:solutions developed for braiding technique of a door sill and for the use ofheavy tows in multi-ply multi-axial fabrics.

Development of preforming technologies & new materials

weft insertingsystems

creel

needletransportchains

warp knittingunit

Results 2000 - 2002

TEchnologies for Carbon fibre reinforced modular Automotive Body Structures

Results 2000 - 2002

Ø Demonstration of the manufacturing feasibility of a structural CF compositepart, by thermoplastic RTM process.

Ø Elaboration of RTM testing tool gathering all geometrical singularitiespresent on a composite floor pan. Development of preforming technologywith reduced tool number and low fabric wastes.

Ø Optimisation of moulding rate considering injection parameters and materialproperties (resin and fabric). Optimisation of injection simulation:development of injection strategies for optimal filling of hollow structuralcomplex shaped part.

Development of improved RTM injection technologies

Comparison between the predicted and experimental flow frontshapes and extents (89 % of complete filling)

Optimization of the preforming process for manufacturing composite floor pan

TEchnologies for Carbon fibre reinforced modular Automotive Body Structures

Final project results in 2004

Ø Design of composite Body in White

Ø Production of 5 composite floor pans as demonstrator parts

Ø Testing of the produced floor pans (stiffness and strength)

Ø Knowledge base in latest technologies to use heavy tow carbon fibre inautomotive structures under heavy loads

Ø Set of software codes (material design / manufacturing process / crash)