Abstract: The aluminum alloy no-rivet clinch connection was used as research object. By testing tensile strength and fatigue mechanical properties of three group lapped specimens with unequal thickness, the fatigue fracture behavior of aluminum alloy no-rivet clinch connection were studied and the load force-life(F-N) distribution of specimens was obtained. According to specimen fatigue test conditions, the equivalent FEA model was established to calculate equivalent structural stress amplitudes(ΔSs), Weibull analysis was carried out on the measured fatigue life scatter data and key parameters of master ΔSs-N(S-N) curve for no-rivet clinch connections were obtained by fitting with the least square method. The fitted master S-N fatigue life curve was applied to predict fatigue damage of no-rivet clinch connections when the all-aluminum hood of pure electric vehicle experiencing dynamic closing load case. Research results suggeste that: the fatigue cracking of no-rivet clinch connections occur at necking position and ΔSs-N curve satisfy power function relation. By optimizing the point number and positon of no-rivet clinch connections, the maximum damage of no-rivet clinch connections in the key area of all-aluminum alloy hoods was reduced from 1.08 to 0.78, which satisfice hood dynamic closing durability performance design requirements of pure electric vehicles. The developed calculation method and master S-N curve parameters may provide a theoretical basis for the fatigue simulation and optimization of no-rivet clinch connections on vehicle bodies.

Key words: all-aluminum alloy hood, no-rivet clinch connection, equivalent structural stress, finite element analysis(FEA), fatigue test

摘要： 以无钉压铆连接铝合金接头为研究对象，通过测试三组料厚不等的搭接试样拉伸强度和疲劳力学性能，研究了铝合金无钉压铆接头失效断裂行为，获得压铆连接试样力寿命（F-N）分布规律。根据试样疲劳测试条件建立等效有限元模型,并计算等效结构应力幅ΔSs，对实测的疲劳寿命散点数据进行Weibull分析,并基于最小二乘法拟合得到无铆连接ΔSs-N（主S-N）曲线关键参数。应用拟合的主S-N曲线进行纯电车型全铝合金引擎盖动态关闭无钉压铆连接疲劳损伤预测，结果表明：无钉压铆接头疲劳开裂发生在颈部位置，其ΔSs-N曲线满足幂函数关系，经连接点数量和位置优化设计，铝合金引擎盖关键区域无钉压铆连接最大损伤由1.08降低至0.78，满足了引擎盖动态关闭耐久性能设计要求。开发的计算方法和主S-N曲线参数可为车身领域无钉压铆连接疲劳仿真与优化提供理论依据。

关键词: 全铝合金引擎盖, 无钉压铆接头, 等效结构应力, 有限元分析, 疲劳试验