Abstract
In this study, a new welding method which utilizes conductivity of CFRTP (Carbon fiber reinforced thermoplastic) is proposed. Electrical current is applied through the CFRTP single-lap joints in thickness direction. Since resistance of joining surface is the highest in the current path, the joining surface is preferentially heated by Joule heating. In this study, surface welding was conducted by the proposed method. By applying constant voltage of 10.3V, the joint-surfaces were heated above melting temperature of the material and were welded. In order to evaluate lap-shear strength (LSS) of welded joints, tensile lap-shear strength tests were conducted. As a result, LSS are 22.0MPa (CF Fabric/PEI) and 22.5MPa (CF Fabric/PPS). These strengths were comparable to those that were welded by traditional resistance welding. It is also found that LSS is changed with welding pressure of joint parts. Also, in order to elucidate the mechanism of self-resistance welding, the temperature of specimen and the current during welding process were measured. As a result, it was found that the process of self-resistance welding could be divided in two stages.
