TC4钛合金激光焊接应力变形有限元分析

基于ANSYS有限元分析软件,采用三维移动热源,对TC4钛合金激光焊接残余应力和变形进行了数值模拟和实验研究.结果表明:钛合金激光焊接产生很大的纵向残余应力,而横向残余应力较小.激光焊接线能量增加时,纵向残余应力拉伸区域变宽,峰值应力降低;而横向残余应力随线能量的增加而升高.在临界焊透规范以上焊接时,随焊接线能量的增大,角变形随之而减小,而横向收缩变形增大.焊件被完全穿透时,线能量对角变形的影响作用降低.钛合金激光焊接变形和残余应力实验结果与数值计算结果吻合性较好.通过焊缝金相实验分析了焊接残余应力和变形与线能量的内在关系.

Finite Element Analysis of Laser Welding Residual Stress and Distortion in Welded Joints of TC4 Titanium Alloy

The laser beam welding residual stress and distortion of titaniuro alloy were investigated by numerical simulation and experimental tests. The finite element calculations were performed using the ANSYS software. The laser beam was modeled as three-dimensional moving heat source. The results showed that the prodigious longitudinal stress was produced in the welded ioints, nevertheless the transverse stress were lower correspondingly. When the heat input increased, the region of tensile of longitudinal stress widened out and its peak value fell, but the magnitude of transverse stress became larger. When the heat input of laser welding exceeded the critical penetration process, with the increase of energy input the angular distortion decreased, but the magnitude of transverse shrinkage increased. As the welding specimens were fully penetrated, the effects of heat input on the angular distortion weakened. Experimental tests were carried out to measure the angular distortion and the distributions of residual stresses in welded joints. The calculated values were in good agreement with experimental measurements. Moreover , the internal relationships of residual stress ,deformation and heat input were further investigated by metallographic section of weld.