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对冷轧钢圆形连接点和矩形连接点的压印接头进行拉伸-剪切试验,研究连接点形状对接头拉伸-剪切性能的影响。并对圆形连接点压印接头进行疲劳试验。试验结果表明,两种接头拉伸-剪切强度和刚度相当。圆形连接点拉伸-剪切过程中的能量吸收值大于矩形连接点,矩形连接点的失效形式为上板拉脱失效。应力比R=0.5,当最大疲劳载荷为接头强度的95%时,接头循环寿命可以达到137万次,为80%时,可以达到疲劳极限500万次。疲劳失效形式为上板接头处产生裂纹,裂纹方向与加载方向大致呈90°。提出了圆形点压印接头的拉伸-剪切强度预测公式和疲劳寿命计算公式,拉伸-剪切强度公式的误差为6.9%。
The tensile-shear tests were carried out on the stamping joints of the round and rectangular joints of cold-rolled steel to study the influence of the shape of the joint on the tensile-shear properties of the joint. Fatigue tests were also carried out on the circular joint embossed joints. The test results show that the tensile strength and the stiffness of the two joints are equivalent. The energy absorption value of the circular connection point during stretching-shearing is larger than the rectangular connection point, and the failure form of the rectangular connection point is the failure of the upper plate to pull off. The stress ratio R = 0.5, when the maximum fatigue load is 95% of the joint strength, the cycle life of the joint can reach 1.37 million times, and when the maximum fatigue load is 80%, the fatigue limit can reach 5 million times. Fatigue failure is caused by cracks in the joint of the upper plate, and the crack direction and loading direction are approximately 90 °. The prediction formula of tensile-shear strength and the calculation formula of fatigue life for circular point stamping joint are proposed. The error of tensile-shear strength formula is 6.9%.