Experimental and theoretical investigation of FRP-steel composite plate under cyclic tensile loading

As the basic element of fiber-reinforced polymer (FRP) strengthened steel structures, FRP-steel composite plate (FSP) is a type of superior composite plate that combines the advantages of steel and FRP. This study combines different types of FRP and steel plates to develop an FSP element. Cyclic tensile tests are conducted to investigate the hysteretic behavior of the FSP, and the yield strength, peak strength, initial stiffness, post-yield stiffness, and residual deformation are analyzed. The experimental results indicate that the stress-strain curves of the FSP are bilinear prior to the fracture of the FRP, and the FSP exhibits a more stable post-yield stiffness and smaller residual deformation than a steel plate, which endows structures with better repairability after an earthquake. A finite element model (FEM) is established to investigate the mechanical behavior and failure process and is validated using experimental results. In addition, a theoretical model based on the composite material superposition theory is proposed and verified to simulate the stress-strain restoring force curves of FSP under cyclic tensile loading. The FEM and theoretical models can guide the practical design of FRP strengthened steel structures.