铝合金薄壁圆筒纵直缝焊接残余应力数值模拟

利用热弹塑性有限元方法对薄壁铝筒纵直焊缝TIG焊进行了数值模拟计算,建立了分析模型,定量地描述了准稳态温度场和残余应力场计算数值以及在整个圆筒上的分布情况,并进行了试验验证.结果表明,焊接时热源周围极窄区域温度高、梯度大,离开热源,温度峰值急剧下降;纵向残余应力在焊缝及热影响区为拉应力,最大值位于焊缝长度中心截面上;纵向残余应力在圆周上表现出拉压区交替变化的趋势.利用应力释放法对焊接件进行应力测量,测量结果与模拟计算结果吻合良好.

Numerical simulation of welding residual stress for longitudinal straight weld seam for aluminum alloy thin-wall cylinder

Numerical simulation of TIG welding of thin wall aluminum cylinder by thermo-elastic-plasic FEM was conducted. Based on the generation of analy sis model, the values and distribution on the whole cylinder for quasi-steady temperature field and residual stress field were described quantitatively.Experiments were performed to verify the residual stress.It can be drawn that during welding there exits high temperature at the centre of heat source and its vicinity where temperature gradient keeps greater.The longitudinal residual stress in weld seam and its HAZ are tensile, its maximum is in the cross-section at the center of weld length and reached 138 MPa.The maximum compressed transverse residual stress was on the both sides of weld seam.The tensile and compressive region of longitudinal residual stress changed alternately at the circumference of cylinder.The residual stress of the welded Al cylinder has been measured by stress-release method, and excellent agreement between the measured value and calculated value is shown.