焊接纵向应力应变动态分布规律的数值模拟

Simulation on Dynamic Welding Longitudinal Stress-Strain Distribution

对低碳钢薄板表面堆焊进行了数值模拟计算,对焊接熔池周围金属的焊接应力应变发展过程进行了分析。在对存在热作用时的压缩应变、拉伸应变进行重新定义的基础上,模拟结果表明,节点的最大压缩应变和最大拉伸应变的和与实际残余总应变相等,最大压缩应变和最大拉伸应变均大于该节点所受的最大热应变。认为实际塑性应变不能表征存在热作用时的金属所承受的压缩应变和拉伸应变的状况,熔池熔宽最大截面并不能确定压缩应变的最终分布形态。数值结果显示,纵向残余拉应力超过常温母材屈服强度区域的宽度和最大实际压缩塑性应变超过0.2%区域的宽度相当,该区域残余实际压缩塑性应变约为0.2%。

The development of welding stress-strain around welding pool was analyzed based on simulation on surfacing refusion of low-carbon steel sheet.The hypothesis that any cross-section retains flat when the sheet is being welded and cooled is not supported by development of relative deformation of 4 pair cross-section.The another definition of tensile strain and compression strain were put forward when the metal is heated or cooled.The data from simulation indicate that,to any point,the sum of the max compression strain and the max tensile strain,which amplitudes are larger than thermal strain,is equal with residual total strain.It couldnt prove that plastic strain is the token of metal status,compressed or stretched when it is affected by heat.The final distribution of compression strain couldnt be determined on the cross-section with max width welding pool.The result shows that the longitudinal residual stress is higher than yield strength of base metal at room temperature where the max plastic strain exceeds 0.2% and that the residual plastic strain is about 0.2% at the same zone.