焊接结构学中的热–力耦合问题简析  

Brief analyses of thermo-mechanical coupling issue on welding structures

作　　者：王苹[1,3] 刘永 常荷茜[2] 董平沙 WANG Ping;LIU Yong;CHANG Hexi;DONG Pingsha(State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology,Harbin 150001,China;Hebei University of Science and Technology,Shijiazhuang 050000,China;Department of Naval Architecture and Marine Structure,University of Michigan,Ann Arbor 48105,USA)

机构地区：[1]哈尔滨工业大学先进焊接与连接国家重点实验室,哈尔滨150001 [2]河北科技大学,石家庄050000 [3]Department of Naval Architecture and Marine Structure,University of Michigan,Ann Arbor 48105,USA

出　　处：《焊接学报》2019年第7期6-11,I0002,共7页Transactions of The China Welding Institution

基　　金：国家自然科学基金资助项目(51605116);国家重点研发计划资助项目(2017YFB12013);哈尔滨工业大学先进焊接与连接国家重点实验室基金资助

摘　　要：针对热加工制造中的热力耦合基础问题,借助基本力学理论,分别研究了一维刚性约束杆、二维平板及满足刚性约束的3-Bar模型在升降温过程中的应力应变演化规律.结果表明,3-Bar模型中加热条带的宽度即为焊接塑性区的宽度;焊接塑性区的纵向残余应力接近材料屈服强度;塑性区大小,塑性区尺寸及其所在位置为焊后变形控制及焊接接头设计关键所在,焊缝塑性区应尽可能接近并对称于结构中性轴分布,以避免产生附加变形;将加热温度峰值与加热宽度输入3-Bar模型,可预测火焰调修控制变形效果.火焰调修时自第二个热循环作用起,残余应力与塑性应变均无法发生改变,调修中反复加热同一区域为无用功.To understand the basic mechanism in the design and manufacture of welded structures,the evolution of stress and strain in the thermal-mechanical coupling process was studied by using one-dimensional bar model with rigid constraints on both ends.The necessary condition for the compressive plastic zones was proposed,namely,the temperature differences should no less than 2ΔT.Under force and moment equilibrium condition,the 1-Bar theory was applied into two-dimensional plates.The 3-Bar model was then developed to study the effects of welding heating and cooling processes on the distribution of two-dimensional longitudinal residual stress.It was found that the width of the local heated strip in 3-Bar model equals to the width of the welding plastic zone.The longitudinal residual stress of the welding plastic zone is close to the material yield strength.The dimension,profile and location of the plastic zone are the key parameters in the design of the weld joint.The asymmetric distribution of the neutral axis should be limited to avoid additional deformations.Flame straightening process was studied using 1-Bar model.It was found that the residual stress and the plastic strain could not be changed from the second thermal cycle.The repeated heating in the repair zone is useless.The effects of flame straightening could be predicted simply by inputting the heating peak temperature and heating width into 3-Bar model.

关 键 词：焊接残余应力 塑性区 3-Bar模型 火焰调修 

分 类 号：TG404[金属学及工艺—焊接]