Dow Automotive Systems has developed a number of CAE material models enabling the virtual validation of different adhesive solutions as joining technology in lightweight design. The project included design and simulation testing of an urban electric vehicle. Bonding was a key joining technology for the multi-material body-in-white (BiW) vehicle.
The vehicle’s validation included stiffness and crash performance in conjunction with aggressive mass reduction targets and the most cost effective use of materials. Leveraging its market and technology leadership in the field, Dow Automotive Systems has been in charge of “structural adhesives for BiW and assembly” aimed at mass production.
A key task has been the development and validation of computer-aided engineering (CAE) models to predict the mechanical behaviour of bonded parts in a crash. The mechanical performance of the bonded substrates has been tested and evaluated, followed by a detailed material characterisation in order to evaluate the different joining concepts and finally develop the CAE-relevant material characterisation. Different tasks were performed by the project partners Laboratorium für Werkstoff- und Fügetechnik (LWF, Uni Paderborn), Institut für Schweißtechnik und Fügetechnik (ISF, TH Aachen) and the Institut für Kraftfahrzeuge (ika, TH Aachen). Tests and evaluation were coordinated and analysed by Ford and Volkswagen.
Looking back at the results, Eugenio Toccalino, Global Director Strategic Marketing at Dow Automotive Systems said: “All modern vehicle concepts target mass reduction, independently from powertrain solutions, although lightweight is even more critical for electric vehicles based on added battery content and vehicle range limitations. Extreme mass reduction can only be achieved implementing a mix of the most modern lightweight materials and adhesive technology becomes a key, if not the only joining technology for such material mix assembly. As a partner in the Light eBody project, Dow Automotive has not only supplied and evaluated different adhesives formulations, but has developed the material models required to design an urban electric vehicle. We are proud to have been chosen as a project partner, based on our leadership in lightweight design and assembly for automotive materials over last 15years.”
To join the different body materials, a one-component epoxy adhesive, Betamate 1422, was applied for conventional grades and then cured during the e-coat process. For high strength Boron steel types a modified version of Betamate 1820 structural adhesive was used instead. To enable hybrid constructions, such as thermoplastic substrates and coated metal, the two-component polyurethane adhesive Betaforce 2850L was chosen. The material models developed in conjunction with the Light eBody project are available at Dow Automotive Systems for customer use.
The project partners
Light-eBody was a joint project of the automobile manufacturers Ford and Volkswagen, other industrial partners and research institutes from Germany. The project partners in particular are: Ford Advanced Research & Development Aachen, Volkswagen Group Research, the Institutes for Automotive Engineering, Welding and Joining as well as Laboratory for Machine Tools and Production Engineering of RWTH Aachen University, Altair Engineering GmbH, Dow Automotive Systems, Fraunhofer LBF, Hydro Aluminium, Laboratory for Joining and Material of University of Paderborn, Linde + Wiemann GmbH KG, Röchling Automotive AG & Co. KG, ThyssenKrupp Steel Europe AG and Wilhelm Böllhoff GmbH & Co. KG.
The project was supported by the German Federal Ministry of Education and Research (Bundesministerium für Bildung und Forschung) in conjunction with the overall aims of Germany’s national plan on electromobility.