Bonding Strength of FRP-Metal Hybrids


  • Gerd Sebastiani imk automotive GmbH
  • Sebastian Pfeifer imk automotive GmbH
  • Lars Röber imk automotive GmbH
  • Jun Katoh Kobe Steel Ltd.
  • Zenzo Yamaguchi Kobe Steel Ltd.
  • Satoru Takada Kobelco Europe GmbH



The lightweight credo “the right material in the right place” raises an interesting concern once different materials are meant to provide a watertight bond. Therefore, we investigate the bonding behavior of metals with Fiber-Reinforced-Plastic (FRP) materials. In order to optimize the bond, the major influencing factors and their interactions are studied.
In order to identify the above interactions, FRP-metal hybrid specimens were investigated with regard to peel forces and shear strengths. During manufacturing the influencing factors such as sheet metal and FRP type, surface treatments, and bonding processes were varied.
Considering the peel force, a thermoset plastic matrix adhesively bonded to steel provided the best results, along with the use of a novel surface etching method by Kobelco. The latter yielded the highest shear strengths within this investigation. No bond could be obtained applying thermoset plastic matrices for in-operandi connections.
Using adhesives or surface treatments introduced additional production costs. Hence, in-operandi bonding would be a favorable option, however, one requiring further research. Compared to the material costs, the additional production costs could prove to be insignificant once the bonding process has been properly robustified and automated.