This study aims to systematically investigate the effects of hole diameter and sheet thickness on the quasi-static and fatigue behaviors of PH-SPR joints of high-strength steel and aluminum alloy. Quasi-static shear and fatigue tests, full-field strain measurements, numerical simulations, and microscopic observations are conducted to analyze the mechanical properties, failure behavior, failure mechanism, and fatigue life. The results indicate that the undercut and bottom thickness decrease with an increase in hole diameter, while the top sheet thickness has a relatively small effect on the undercut and bottom thickness. The mechanical properties of PH-SPR joints decrease with an increase in hole diameter and increase with an increase in sheet thickness. The J16-5.5 joint exhibits the highest fatigue performance, the fatigue life of J16-5.5 joints is 5.3 times, 7.8 times, and 3.98 times higher than that of J12-5.5, J12-6.0, and J16-60 joints under a load level of 5.0 kN. This indicates that increasing the hole diameter reduces the fatigue life while increasing the sheet thickness can enhance the fatigue life. The localized stress concentration and fretting wear on the top and bottom sheets contribute to the fatigue fracture of both sheets.

中文翻译：

---

孔径和板材厚度对预孔自冲铆接钢铝接头准静态和疲劳行为的影响研究


本研究旨在系统研究孔径和薄板厚度对高强度钢和铝合金 PH-SPR 接头准静态和疲劳行为的影响。进行准静态剪切和疲劳试验、全场应变测量、数值模拟和微观观察，以分析机械性能、失效行为、失效机理和疲劳寿命。结果表明：随着孔径的增加，底切和底厚减小，而顶板厚度对底切和底厚的影响相对较小。PH-SPR 接头的机械性能随孔径的增加而降低，而随着板材厚度的增加而增加。J16-5.5 接头表现出最高的疲劳性能，在 5.0 kN 的载荷水平下，J16-5.5 接头的疲劳寿命分别是 J12-5.5、J12-6.0 和 J16-60 接头的 5.3 倍、7.8 倍和 3.98 倍。这表明增加孔径会缩短疲劳寿命，而增加板材厚度可以提高疲劳寿命。顶部和底部板材上的局部应力集中和微动磨损会导致两种板材的疲劳断裂。