钛合金大厚度试件电子束焊接残余应力有限元分析

基于热弹塑性有限元理论,建立了钛合金大厚度试件电子束移动热源的焊接残余应力三维数值分析模型,分析研究了厚度为75 mm的TC4电子束焊接试件残余应力分布规律。计算结果表明,大厚度电子束焊接试件在焊缝及其附近宽度约40 mm的范围内存在极其复杂残余应力,试件表面的焊缝及其附近20 mm左右的区域存在着对结构强度有利的横向残余压应力,但试件内部残余应力水平要高于表面的残余应力,尤其是在距起始和收尾端10mm及约1/4厚度处的区域,存在着三向的残余拉应力,且数值较高,对钛合金平板电子束焊接接头力学性能将具有重要影响,应引起足够的重视。钛合金平板电子束焊接残余应力的计算结果与实测结果基本一致。

FEM ANALYSIS OF WELDING RESIDUAL STRESSES IN A THICK PLATE EBW JOINT OF TITANIUM ALLOY

Based on the thermal-elastic-plastic FEM theory, a three-dimensional numerical model is set up for studying the welding residual stresses in the thick titanium plate by electron beam welding. The computation results show that there exist the very complex residual stresses in the EBW thick plate joint, and there is the transverse residual compression stress at the area near the weld on the surface, which is useful for the structure strength. But the residual stress value in the welded joint is generally more than that on the surface, especially there is three-dimensional and large residual tensile stress at the region near to the upper surface. The residual stress measurements verify the conclusion.