ON THE DELAMINATION OF CFRP AND EPOXY ADHESIVE INTERFACE USING LASER SHOCK ADHESION TEST (LASAT)

For a reduction of aircraft structural weight is strongly demanded, Carbon Fiber Reinforced Plastics (CFRP) has been widely used, since it has enormously lightweight and excellent specific strength, compared to metallic materials. In addition, for the joining technology of dissimilar materials, adhesive bonding has been actively developed instead of mechanical fastening such as bolts and rivets. In addition to understanding static mechanical characteristics, the development of advanced transport aircraft needs to clarify dynamic behavior and impact response. However, there are few studies on adhesive bonding strength of CFRP under ultra-high strain rate which ranges from 10(6) to 10(7) 1/s. To achieve the purpose of bonding strength evaluation under such high strain rate, this study employed Laser Shock Adhesion Test (LaSAT) to evaluate the adhesive strength of CFRP and epoxy resin adhesive under high strain rate. LaSAT, which employs a laser ablation, induces strong shock wave, resulting in interfacial delamination under high strain rate. When the tensile stress wave reaches the critical strength, the interfacial delamination occurs. Moreover, CFRP laminate can change its mechanical property by changing the direction of carbon fiber in each stacking sequence. This study prepared two types of CFRP, i.e. UD-CFRP (Unidirectional fiber reinforcement composite) and QI-CFRP (Quasi-Isotropic composite). Using these two types of CFRP, this study investigated the effect of CFRP stacking sequence on the interfacial delamination morphology due to LaSAT. The delamination morphology and bonding strength of CFRP/epoxy resin adhesive were investigated.