Joining technologies for multi-material-design

From an industrial point of view, joining technologies play a key role nowadays, due to the continuously increasing applications of multi-material-design. The different properties of the used materials lower the number of possible (suitable) joining technologies. Fiber-Reinforced-Plastics (FRPs) make it even more difficult to choose the right technology because of their anisotropic behavior. Bonding is currently the most common technology for joining FRPs. Furthermore, hybrid joining processes are applied in order to combine the positive properties of other joining technologies with bonding. Nevertheless a blatant disadvantage of bonding FRPs is the fact, that there are no fibers in the direct area of the join which leads to a weakened structure and lower mechanical properties. Friction Stir Welding can avoid this disadvantage when joining short fiber-reinforced thermoplastics by stirring fibers into the joining area. To be able to apply the Friction Stir Welding technology to thermoplastic materials, certain changes in the process parameters are necessary because the technology has its origin in the metallurgy.