TECABS. TEchnologies for Carbon fibre reinforced modular Automotive Body Structures VOLKSWAGEN AG. SAERTEX Wagener GmbH & Co.KG.

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1 VOLKSWAGEN AG SAERTEX Wagener GmbH & Co.KG KU Leuven This project is supported by the European Commission TECABS TEchnologies for Carbon fibre reinforced modular Automotive Body Structures Volvo Car Corporation More information available at: Willems & van den Wildenberg Telephone ICMA alusuisse airex composites

2 Summary Development of technologies and methods enabling the realisation of a composite Body in White (BIW) concept in 50 units/day series of commercial cars and a 50% weight reduction based on the use of low cost heavy tow carbon fibre textiles, finally resulting in a reduction of CO 2 emission. By using complex shaped multi-functional parts and smart joining technologies, the number of parts could be reduced to 30% (present 200+). It is assumed that a reduction of parts which results in less tooling and joining equipment makes a composite BIW concept cost effective even if the manufacturing costs per single part are still expected to be higher. Total project budget: 5.2 million and is supported by EC under the R&D research program Growth. Project started in April 2000 and ends in April 2004 Large consortium of automotive car manufacturers, suppliers and research institutes in Europe to investigate technologies enabling the development of a lightweight Carbon Fibre Reinforced Plastics(CFRP) BIW.

3 Project objectives Development of technologies and methods enabling the realisation of a composite Body in White concept in 50 units/day series of commercial cars and a 50% weight reduction based on the use of low cost heavy tow carbon fibre textiles, using: high speed low cost RTM processes and cost effective / high speed preform and resin technologies simulation technologies of static / crash behaviour and economic & environmental performance modular methodology to translate performance requirements into feasible part concepts using these new technologies The project results in each of these exploitable technologies and validates the integrated achievements by means of testing a full-scale multi-functional floor pan as a demonstrator part under various conditions.

4 Results realised during the first 30 months of the project: April 00 - Oct. 02 Conceptual design of composite Body-In-White completed Detailed design of multifunctional composite floor pan completed Elaboration of LCI methodology based on input/output data of energy and CO 2 emission completed Development of part performance simulation tools (CAE) Development of crash concepts & simulation tools Development of preforming technologies & new materials Development of improved RTM injection technologies

5 Design of composite Body in White (BIW) Elaboration of package and structural requirements of the Body in White Composite BIW concept and detailed design of floor pan completed Split up of floor pan into several sub-preforms sandwich & monolithic FEA calculations have been performed using NASTRAN based on laminate modelling; PUCK s 2D-failure criterion implemented in PATRAN Development and design of joining technologies (bonding & load introduction concepts); selection, FEA and testing of bolted and bonded CFRP specimen Steel BIW Target BIW 18 months BIW 24 months Weight 203 kg 50%=102 kg 80 + x kg* 79 + x kg* Number of Parts %= x* 64 + x* Static Stiffness 22.9 min 22.9 min 30.7 min 25.5 min Dyn. Tors. Stiffness 40 Hz 100% 68 Hz 71 Hz Dyn. Bend. Stiffness 43 Hz 100% 60 Hz 61 Hz * not all functions integrated

6 Development of part performance simulation tools (CAE) Geometry: Development of a universal description of yarns inside a textile, mathematical models and software package Wisetex. Large Strain Deformation (draping): Geometry description + load-deformation curves (except for NCF) Mechanical Performance: The stiffness matrix can be built (except for deformed reinforcement). Permeability: Mathematical formulation of models for permeability of textile reinforcements based on Lattice Boltzmann approach. Development of software package Flowtex (not for deformed non-crimp fabric unit cell). Developments of a theoretical method to calculate both saturated and average permeability tensors using fluid mechanics software Fluent. Link established with the geometrical description from Wisetex. Cost Prediction tool: Based on industrial data cost prediction tool developed and and under validation now. CAE TOOLS: Crash simulation software (PAM-CRASH) can read/use draping results (PAM-FORM). RTM simulation software (PAM-RTM) can read/use draping results (PAM-FORM). Woven fabrics geometry representation Resin velocity inside a unit cell of a quadri-axial fabrics

7 Development of crash concepts and simulation tools Composite crash analysis on modelling delamination of large-scale complex structures, braided samples & trials with NCF Physical crash testing of tubes, braided and NCF with various fibre lay up Implementation of crash tests and new models in PAMCRASH software to study ply delamination and a new technique for crash prediction behaviour of axial crushing of composite sections. 1st design of frontal crash parts and structure based on high-speed deformation demands, using ABACUS and new models in PAMCRASH Fracture initiation Fracture propagation 3D crushing /fracturing zone Potential crushing, buckling, delamination, transverse cracking, etc. zone

8 Development of preforming technologies & new materials Worldwide screening of low cost heavy tow carbon fibres from 24k to 80k. Selection of a thermoset epoxy resin system, and a potential toughener. Characterisation of mechanical properties, drapability and permeability of non-crimp fabrics, braids and their composites. Screening of heavy tow carbon fibre yarns applicable for thermoplastic resin RTM, and manufacturing of dedicated fabrics. Development of textile processes for the production of carbon fibre fabrics: solutions developed for braiding technique of a door sill and for the use of heavy tows in multi-ply multi-axial fabrics. creel warp knitting unit needle transport chains weft inserting systems

9 Development of improved RTM injection technologies Demonstration of the manufacturing feasibility of a structural CF composite part, by thermoplastic RTM process. Elaboration of RTM testing tool gathering all geometrical singularities present on a composite floor pan. Development of preforming technology with reduced tool number and low fabric wastes. Optimisation of moulding rate considering injection parameters and material properties (resin and fabric). Optimisation of injection simulation: development of injection strategies for optimal filling of hollow structural complex shaped part. Optimization of the preforming process for manufacturing composite floor pan Comparison between the predicted and experimental flow front shapes and extents (89 % of complete filling)

10 Final project results in 2004 Design of composite Body in White Production of 5 composite floor pans as demonstrator parts Testing of the produced floor pans (stiffness and strength) Knowledge base in latest technologies to use heavy tow carbon fibre in automotive structures under heavy loads Set of software codes (material design / manufacturing process / crash)