抄録
This paper describes a numerical study of welding strength between a thermoset carbon fiber-reinforced plastic (CFRP) and a thermoplastic resin, which forms a complicated interface (prepared by welding technology). Plane stress conditions were assumed and a finite element method (FEM) with continuum damage mechanics (CDM) and cohesive zone model (CZM) was applied for the numerical study. Shear strain was applied until the model fractured, or the strain reached 4% for several cases, in which the position of the interface between the thermoset resin (TS) and thermoplastic resin (TP) differed. A structure in which the TS/TP interface overlaps with the carbon fiber (CF) layer resulted in an increase in welding strength because the CF that lies along the TS/TP interface bears the shear stress. For validation, the numerical study results were used to explain the experimental results. A lap shear test was conducted to evaluate the interfacial strength. An increase in lap shear strength was achieved using the welding technology, and a complicated fracture surface especially fiber breakage at the surface of the welding was observed, indicating that the CF bears the stress, which is an important factor in welding technology. The increase in lap shear strength by the integrated structure can be explained without fiber breakage using the results of numerical simulation.
