钻孔DMI应变计法测定点焊残余应力基础研究

摘要

针对目前测定点焊残余应力的方法在工程应用上的局限性,提出了将DMI应变计与钻孔法相结合的钻孔DMI应变计法.通过建立点焊件的力学模型,推导得到了钻孔DMI应变计法基本方程,并由数值标定的方法得到释放系数表.结合示例验证了该方程的正确性,同时也简述了测量的具体步骤.并采用有限元模拟的方法,从工件的最小边距、连接件尺寸、焊点直径与板厚比、钻孔深度4个方面分析了钻孔DMI应变计法的适用范围.%In view of the limitation of the current method for measuring residual stress of spot welding on engineering application, the DMI strain gauge method is proposed, which combines the DMI strain gauge with the drilling method.By establishing the mechanical model of spot welding work piece, the basic equation of DMI strain gauge hole drilling method is deduced, and by the method of numerical can be obtained the release coefficient table.The example verify the correctness of the basic equation, and also illustrates the specific steps of measuring.Finally, using the finite element method, from the minimum margins, workpiece size, spot diameter and connection plate thickness ratio, drilling depth four aspects analyzes the scope of application of DMI drilling strain gauge method.