Single-pull Process of CFRP Reinforced Steel Double-lap Structures based on AE Characteristic Parameters

In this study, the mechanical properties and damage evolution of CFRP reinforced steel double lap structures under uniaxial tensile conditions were analyzed by using acoustic emission (AE) characteristic parameters. CFRP reinforced steel double lap structure members were prepared by grinding (group P), sandblasting (group G) and pre-coating silane coupling agent (group GS). The acoustic emission signal of uniaxial tensile process was collected by acoustic emission instrument. By using AF-RA parameter correlation analysis, the mechanical properties of CFRP reinforced steel double lap structure under uniaxial tensile were studied. The results show that the average limit load of group GS (49.61kN) and failure displacement of group G (1.36mm) are the highest, which are 67.9% and 15.2% higher than that of group P, respectively. The failure mode is mainly interfacial debonding. The chemical bond enhancement of GS group shows CFRP-adhesive debonding, while the physical roughness treatment of P and G group is more likely to cause the interface debonding of steel-adhesive layer. The analysis of acoustic emission characteristic parameters shows that the damage process can be divided into three stages: initial damage, damage expansion and final failure. Through AF-RA correlation analysis, it was found that the proportion of shear damage increased exponentially with the slope of the boundary line, and the number of shear damage was dominant (60%-70%).