摘要
采用热加工历史不相关的屈服强度-温度单自变量材料模型进行热处理强化铝合金的焊接残余应力有限元分析,通常得到与材料屈服极限R_(P0.2)相当的纵向残余拉应力,这与实际测量结果明显不符。针对这一问题,通过分析热处理强化铝合金在焊接过程中经历的热循环、组织及性能变化特点,提出了包含固溶-软化和时效-硬化现象的热处理强化铝合金的热加工历史相关材料模型,建立了屈服强度与时间-空间-温度均相关的三自变量函数关系式。将该模型用于淬火-自然时效态2A12-T4铝合金TIG焊过程的有限元分析,得到53%R_(P0.2)的纵向残余应力,数值模拟的准确性具有实质性的改进。
The residual stresses in heat treatable 'aluminum alloy welds obtained by the FEM analysis using non history related temperature dependent yield strength model are usually of the same level to the yield strength,which does obviously not accord with the measured results.On the basis of analyzing the evolution characteristics during welding,such as thermal cycle,microstructure and property changes,a hot processing history related material model was developed for heat treatable aluminum alloys to take into account the solution of softening and precipitating hardening phenomena,and a corresponding three variable function of yield strength was put forward which is not dependent on only temperature but also the time and position.The new model was then used in the numerical simulation of GTA welding of alloy 2A12-T4 under quench and natural aged condition.The results show that the obtained residual longitudinal stress is 53% of the yield strength,which indicates that the substantial improvement in simulation accuracy was realized.
出处
《焊接》
北大核心
2009年第6期18-22,共5页
Welding & Joining
关键词
热处理强化铝合金
焊接
有限元
焊接残余应力
材料模型
heat treatable alloy
welding
finite element analysis
residual stress
material model
