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首次提出了用于汽车生产中分瓣模压印连接接头强度和失效形式的预测方法。根据接头静力学测试中的颈部断裂失效和上下板拉脱失效两种失效形式分别建立了压印接头的两个强度预测公式,2pπ2N N NF A R t t()和2p pπt b s F R,公式以接头颈部厚度Nt和镶嵌量Ut为重要的中间变量。强度预测公式表明:对于颈部断裂的压印接头,颈部厚度值tN越大,接头强度越高;对于拉脱失效的压印接头,接头强度取决于颈部厚度tN和镶嵌量tU,两者之和越大,接头强度越高,并且镶嵌量对接头强度的影响与颈部厚度相比更大。对颈部厚度变化范围为0.35mm~0.56mm、镶嵌量变化范围为0.045mm~0.45mm的15种组合接头,根据强度预测公式计算了接头强度,并进行了拉伸-剪切试验。将计算结果与试验结果进行对比,结果表明二者吻合较好,最大接头强度误差为8.9%。这说明本文建立的接头强度预测公式能够准确地预测压印接头拉伸-剪切过程的强度和破坏形式。
For the first time, a prediction method for the strength and failure modes of split-die imprinted connectors used in automobile production was first proposed. According to the failure modes of neck failure and pull-off failure of upper and lower plates, two formulas of strength prediction of stamping joint are established respectively. The formulas are as follows: 2pπ2N N NF AR tt () and 2p pπt bs FR, Neck thickness Nt and inlay Ut are important intermediate variables. The strength prediction formula shows that for the imprinted joint with broken neck, the greater the value of the neck thickness tN is, the higher the strength of the joint is; the strength of the joint depends on the thickness of the neck tN and the amount of tU for the pull-failure imprinting joint The greater the sum of those, the higher the strength of the joint, and the greater the amount of inlay on the strength of the joint compared to the thickness of the neck. Fifteen kinds of joints with varying thickness range of 0.35mm ~ 0.56mm and 0.045mm ~ 0.45mm were used to calculate the joint strength according to the strength prediction formula. The tensile and shear tests were carried out. The calculated results are compared with the experimental results. The results show that the two agree well with the maximum joint strength error of 8.9%. This shows that the joint strength prediction formula established in this paper can accurately predict the strength and failure mode of the tensile-shear process of stamping joints.