铝合金自冲铆接头静力学性能及失效机理分析

Static mechanical properties and failure mechanism of self-piercing riveted aluminum alloy joint

选择不同结构的自冲铆接头,进行静力学测试获得其静力学性能.采用学生氏t分布对试验数据进行统计分析,以检验数据有效性.选择宽板接头失效断口进行扫描电子显微(SEM)观察,从而研究接头失效机理.结果表明,板材宽度和铆钉数量的增加均可有效增强接头静力学性能,其中铆钉数量的影响程度更为突出.接头宏观静态失效模式均为下板脱离,板材宽度和铆钉数量会影响基板变形程度.SEM分析表明,上板主要承受拉伸,断裂部位呈现韧窝结构,最终影响接头失效位移.下板承受拉伸和压缩,其变形特征对强度和位移均有影响.

The static mechanical properties of self-piercing riveted( SPR) joints with different structures were investigated by static mechanical tests. The experimental data were analyzed by statistics in Student's t distribution to verify the effectiveness of the data. The failed surfaces of wide joints were observed with scanning electron microscopy( SEM) to study the failure mechanism. The results show that the static mechanical properties of SPR joints could be enhanced by improving the wideness of sheet and especially the number of rivets. The macroscopic static failure mode of joints was pull-out of lower sheet.The deformation of substrate was influenced by the wideness of sheet and number of rivets. The analysis of SEM indicates that the state of upper sheet was mainly tensile,and dimple structure presented at failed location,both influenced the failure displacement of joints. The tensile and compressive states existed in the lower sheet,which affected the strength and displacement of joints.