模态试验法测试焊接残余应力机理分析及模型参数估计  

Mechanism analysis and model parameters estimation of welding residual stress measurement based on modal test method

作　　者：甘世明[1,3] 徐艳文 韩永全 翟之平[1] GAN Shiming;XU Yanwen;HAN Yongquan;ZHAI Zhiping(Inner Mongolia University of Technology,Hohhot,010051,China;Materials Forming Key Laboratory,Inner Mongolia University of Technology,Hohhot,010051,China;Inner Mongolia Key Laboratory of Mechanical&Electrical Control,Hohhot,010051,China)

机构地区：[1]内蒙古工业大学,呼和浩特010051 [2]内蒙古工业大学,材料成型重点实验室,呼和浩特010051 [3]内蒙古自治区机电控制重点实验室,呼和浩特010051

出　　处：《焊接学报》2023年第8期34-40,I0005,共8页Transactions of The China Welding Institution

基　　金：国家自然科学基金资助项目(52165034);内蒙古自治区直属高校基本科研业务费项目(JY20220214);内蒙古工业大学科学研究项目(BS2021033).

摘　　要：为避免残余应力对焊接结构的不利影响,保证其可靠性,需要探究残余应力分布.模态试验法因具有快速和无损的特点,逐渐应用于残余应力测试.为实现模态试验法测试焊接残余应力,通过振动理论分析了模态试验法的机理,获得了薄板焊件中残余应力与固有频率的关系;薄板焊件中的残余拉应力使固有频率减小,残余压应力使固有频率增大.在此基础上,将钻孔法和模态试验相结合,借助数据拟合的方法,估计了模态试验法测试6 mm 7A52铝合金试板VPPA-MIG(variable polarity plasma arc-metal inert gas)复合焊接残余应力的模型参数,确立了固有频率与残余应力的数值关系.依据确立的数值关系,测得了7A52铝合金试板在不同复合焊接参数下的纵向残余应力分布.结果表明,接头各区域的残余应力分布特征与钻孔法测得的结果基本一致,偏差在4%范围之内,估计出的模型参数能够保证模态试验法测试结果的可靠性,实现了焊接残余应力的快速和无损测试.To reduce the negative influence of welding residual stress on the welded structure and guarantee the reliability of structure,it is necessary to explore the distribution of residual stress in the welded structure.Modal test method has been gradually applied in the measurement of residual stress due to its fast and non-destructive characteristics.In order to measure welding residual stress by modal test method,the mechanism of modal test method was analyzed by vibration theory,and the relationship between residual stress and natural frequency in thin plate welded structure was obtained.The residual tensile stress in the thin plate welded structure can cause the decrease of natural frequency,while the residual compressive stress can cause the increase of natural frequency.On the basis of theoretical analysis,the hole-drilling method and modal test experiment were combined,and the model parameters for measuring the residual stress of 6 mm 7A52 aluminum alloy(variable polaritypolarity plasma arc-metal inert gas,VPPA-MIG)hybrid welded plate using modal test method were estimated through the method of data fitting.The numerical relationship between natural frequency and residual stress was established.According to the established numerical relationship,the longitudinal residual stress distribution of 7A52 aluminum alloy plates under different hybrid welding parameters were measured through modal test experiment.The results illustrate that the distribution characteristics of residual stress measured by modal test method in each zone of the hybrid welded joint of 7A52 aluminum alloy plates are consistent with the results measured by holedrilling method,and the deviation between the residual stress values measured by the two methods is within the range of 4%.Therefore,the estimated model parameters can guarantee the reliability of the measurement results of the modal test method.It has been achieved fast and non-destructive measurement of the welding residual stress using modal test method.

关 键 词：模态试验 残余应力 固有频率 模型参数估计 变极性等离子弧-熔化极气体保护复合焊接 

分 类 号：TG456.2[金属学及工艺—焊接]