Self-piercing riveting (SPR) is one of the advanced mechanical joining techniques, and it has been widely used in automobile industry. In this paper, the effect of die misalignment on the cross-section parameters and mechanical properties of SPR joints were respectively studied through numerical simulation and experiment, and the mechanical properties degradation mechanism of the misaligned riveted joint were analyzed. A three-dimensional explicit finite element model (FEM) of SPR joint was developed by ABAQUS, and the section observation was performed to evaluate the accuracy of FEM. The riveting process and the strain of SPR joints with different misalignment distance was analyzed, and the quasi-static shear test was carried out. The results revealed that the rivet leg near the die edge was thickened due to limitations in deformation space, and a cavity was formed at the outer edge of the rivet leg near the die center, during the riveting process. It resulted in different cross-section parameters and mechanical properties of SPR joints. Specifically, the interlock distance decreased as the misalignment distance increased. The bottom thickness of the side near the die edge increased with increasing misalignment distance, while that near the die center decreased slightly as the misalignment distance increased. In addition, the maximum shear load decreased nonlinearly with increasing misalignment distance, and the movement of die along the loading end had a significantly greater impact on the maximum shear load than the movement along the fixed end. This was mainly because the interlock distance of SPR joints was asymmetrically and nonlinearly reduced due to the die misalignment.

自冲铆接（SPR）是先进的机械连接技术之一，在汽车工业中得到广泛应用。本文通过数值模拟和实验分别研究了模具失位对SPR接头截面参数和力学性能的影响，并分析了失位铆接接头力学性能退化机理。利用ABAQUS建立了SPR接头三维显式有限元模型（FEM），并通过截面观察评价FEM的精度。对不同偏心距离的SPR接头的铆接过程和应变进行了分析，并进行了准静态剪切试验。结果表明，在铆接过程中，由于变形空间的限制，靠近模具边缘的铆钉腿变厚，并且在靠近模具中心的铆钉腿外缘处形成了空腔。这导致SPR接头的截面参数和力学性能不同。具体而言，随着错位距离增大，互锁距离减小。靠近模具边缘一侧的底部厚度随着错位距离的增加而增加，而靠近模具中心的一侧的底部厚度随着错位距离的增加而略有减小。此外，最大剪切载荷随着错位距离的增加呈非线性下降，并且模具沿加载端的运动对最大剪切载荷的影响明显大于沿固定端的运动。这主要是因为模具未对准导致SPR接头的互锁距离不对称且非线性地减小。