A finite element investigation into the continuous induction welding of dissimilar material joints

European LS-DYNA Conference 2015 Session # 1-1 A finite element investigation into the continuous induction welding of dissimilar material joints Miro Duhovic, Martina Hümbert, Peter Mitschang, Joachim Hausmann Institut für Verbundwerkstoffe GmbH, Erwin-Schrödinger-Str., Building 58 67663 Kaiserslautern, Germany Pierre L’Eplattenier , Inaki Caldichoury Livermore Software Technology Corporation, 7374 Las Positas Road, Livermore, CA 94551, USA miro.duhovic@ivw.uni-kl.de Tel.: +49 631 2017-363 Abstract Continuous induction welding is an advanced material processing method with a very high potential of providing a flexible, fast and energy efficient means of joining together thermoplastic composites to themselves and metals and alloys. However, selection of the processing parameters and optimization of the process is very difficult as it involves the interaction of up to four different types of physics. In addition, many different material combinations including materials with low or high electrical conductivity, thermal conductivity and heat capacity, make the intuitive selection of processing parameters impossible. In this work, a simulation test-bed, setup for the continuous induction welding of two material partners and their corresponding physics interactions is used to investigate the induction welding possibilities for several combinations of hybrid material joints. The materials include 2mm thick plates of structural grade aluminium (Al) and steel (St) along with polyamide 6 (PA-6) thermoplastic prepregs containing either glass (GF/PA6) or carbon fiber (CF/PA6) reinforcements. Six different material combinations are investigated (Al-GF/PA6, Al-CF/PA6, St- GF/PA6, St- CF/PA6, CF/PA6-GF/ PA6 and CF/PA6-CF/PA6) along with their appropriate weld orientation (i.e. on which side of the material stack the coil should face). A target characterization temperature of 200°C for all material combinations is taken (lower than the actual recommended weld temperature of ~260-280°C) in order to be able to compare simulations to the physical tests performed. A pancake type induction coil with a constant coupling distance but different coil current and consolidation roller-tocoil distance is used together with variable welding speeds to achieve the required welding temperature drop necessary for adhesion to take place. The induction frequency (540 kHz) remains constant.