厚板柱坡口多层焊瞬时温度场的有限元计算

The Calculation of Transient Temperature Field in Heavy Welded Shapes by Finite Element Method

焊接弹塑性热应力计算的基础是瞬时温度场的确定。本文作为厚板焊接柱残余应力有限元分析的一部分,考虑了钢材的热物理性能随温度的变化,对厚板柱坡口多层焊接过程进行了非线性热传导计算。在计算程序中以集中质量热容矩阵代替协调质量热容矩阵,克服了瞬时温度场有限元计算中的温度波动现象,取得了满意的计算结果。结合弹塑性热应力分析,计算了5个厚板焊接箱形、4个厚板焊接工字形截面往焊接过程中的瞬时温度分布。

For calculating thc elastoplastic thermal stresses caused by welding, it is importantto determine the transient temperature field. As a part of finite element analysis for weld-ing residual stresses, this paper analyses the nonlincar heat conduction of multipass weldsin heavy welded shapes considering the effect of the temperature on the thermo physicalproperties of steel, in which the lumped mass heat capacity matrix takes the place of theconsistent mass heat capacity matrix, so the temperature fluctuation is overcome, and agood calculating result is obtained. Based on the analyzing the elastoplastic thermalstress caused by multipass welding in heavy welded shapes, the transient temperaturefields of five box-section and four H-section columns during welding are calculated.