Study on tensile properties of Z-pin reinforced bismaleimide resin matrix composites with single lap joints

The objective of this study is to examine the influence of Z-pin implantation parameters on the load-bearing effectiveness of single lap joints reinforced with Z-pins. This study explores the effect of Z-pin implantation parameters on the load-bearing performance of the joint. Concurrently, a finite element simulation is employed to conduct a comprehensive analysis of the stress distribution and failure mode of the joint throughout the damage process. Furthermore, high-temperature tensile tests were conducted to evaluate the impact of temperature on the Z-pin reinforcement mechanism. The findings demonstrated that Z-pin reinforcement markedly augmented the peel resistance at the joint extremities, thereby postponing the inception of fissures. The maximum shear stress at the joint end exhibited a 4.81-fold increase. During the loading process, the presence of Z-pins effectively impeded the propagation of cracks, thereby enhancing the load-carrying capacity of the joint. The reinforcement effect of Z-pins exhibited variability with respect to the implantation area, with a maximum increase of 41.6%. The load capacity of the joint reached 2.51 kN/g per unit mass. However, as the temperature increased, Z-pin pull-out occurred, leading to a reduction in reinforcement efficiency. At high temperatures, frictional forces during Z-pin pull-out became the primary mechanism for dissipating crack propagation energy. These findings provide valuable insights into optimizing Z-pin reinforcement strategies for enhancing the mechanical performance of composite joints, particularly under varying thermal conditions.Highlights The efficiency of different pin positions was evaluated. Evaluation of Z-pin enhancement efficiency using joint loading efficiency. Establishment of a high-precision finite element model with Z-pin. Analyzed the damage process of joints at high and normal temperatures. Study the failure form of Z-pin at high temperature.