环形加筋圆柱壳的焊接残余应力及振动特性研究

Investigation on welding residual stress and vibration characteristics of ring-stiffened cylindrical shell

[目的]旨在评估环形加筋圆柱壳的复杂焊接残余应力及其对结构振动特性的影响等。[方法]首先,采用二氧化碳气保焊实现环形加筋圆柱壳的焊接,使用非破坏性的X(XRD)测量关键区域焊接后以及退火热处理后的焊接纵向残余应力。其次,通过高效的热−弹−塑性有限元计算,分析焊接过程中的温度场和残余应力,并研究移动体热源和固定热源模型对焊接模拟结果的影响。最后,在自由状态下测试环形加筋圆柱壳焊接后以及退火热处理后的结构振动特性,并通过有限元法预测结构振动模态及其固有频率。[结果]基于试验测量、焊接热−弹−塑性以及结构模态有限元计算,得到了环形加筋圆柱壳热处理前后的残余应力和振动特性。[结论]固定热源模型可以高效地预测环形加筋圆柱壳的热力学响应,预测的焊接残余应力与测量结果基本一致;退火热处理工艺可以有效消除焊接残余拉应力,且焊接残余应力对环形加筋圆柱壳的振动特性影响甚微。

[Objective]This study investigates complex welding residual stress and its effect on the vibration characteristics of a ring-stiffened cylindrical shell.[Methods]Fusion welding with carbon dioxide as the shield gas is employed to finish the welding of a ring-stiffened cylindrical shell.The non-destructive X-ray diffraction(XRD)approach is used to measure the longitudinal residual stress of critical regions after welding and annealing heat treatment.Effective thermal elastic-plastic finite element(FE)computation is then used to examine the temperature and welding residual stress during welding,as well as considering the influence of the moving body heat source and fixed heat source on welding computation.Under the state of freedom,the vibration characteristics of the examined ring-stiffened cylindrical shell after welding and annealing heat treatment are measured,and the vibration modes and corresponding natural frequency are both predicted with FE analysis.[Results]Based on experimental measurement,thermal elastic-plastic FE computation measurement during welding and structural vibration is carried out,and the residual stress and vibration characteristics of the ring-stiffened cylindrical shell after welding and annealing heat treatment are obtained.[Conclusions]A fixed heat source can effectively predict the thermal and mechanical response during the welding of a ring-stiffened cylindrical shell,and the predicted welding residual stress shows good agreement with the measurements.Annealing heat treatment can significantly reduce welding residual stress and lower its influence on the vibration characteristics of a ring-stiffened cylindrical shell.