One main problem during simulation of welding process is the long computational time and large need of memory size by thermal-elastic-plastic finite element method.As the heat affected zone is in highly nonlinear state with great temperature and stress-strain gradients,the mesh for the region should be fine enough;while other region away from the weld line remains elastic, and the mesh can be much coarser.Therefore, the welded structure can be frequently rezoned, making the fine mesh follow with the heat source,in order to minimize the computing effort.The study presents the three-dimensional rezoning technique,which enables the solution variables to be mapped from the old mesh to the new mesh.The flat plate and pipe welding model are simulated with and without rezoning technique;temperatures, welding deformations and residual stresses are compared.By employing rezoning technique,30％ of computational time is reduced when keeping good accuracy in results.%在结构焊接数值模拟中,运用热弹塑性有限元方法进行分析的主要问题是计算时间长、内存需求大.由于热影响区具有高度的非线性特征,温度、应力应变梯度较大,单元应当划分得很细;而远离焊缝的绝大部分区域仍然处于线弹性状态,单元可划分得相对较粗.这样就可对焊接构件不断进行网格重新划分,使细密的网格随着热源一起移动,从而减少计算的规模.研究了三维六面体网格重划分技术,进行不同网格之间的变量映射,实现模型网格重划分前后分析步的衔接.对平板和圆管的焊接分别进行了网格重划分和完整网格模型条件下的数值模拟,提取了焊接温度、焊接变形和残余应力.结果表明,网格重划分技术在保证计算精度的前提下,提高约30%的计算效率.
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