焊接过程数值模拟材料参量的确定

使用随温度变化的材料热—力学参量,研究了屈服强度、热导率、比热容、弹性模量、线膨胀系数、密度及泊松比7个热物理与力学参量对焊接残余应力峰值的影响.结果表明,屈服强度和热导率的变化范围较大,对纵向残余应力峰值影响显著;比热容、弹性模量、线膨胀系数和密度的变化范围较小,对纵向残余应力峰值影响不大;泊松比的变化范围与线膨胀系数和密度的相当,但对纵向残余应力峰值影响非常小.使用切条释放法对铝合金2A12-T4平板中纵向焊接残余应力模拟结果进行试验验证,模拟结果与试验结果吻合良好,证明了模拟结果的正确性.

Determination of material parameters for welding process simulation

Thermo-mechanical parameters varied with temperature were used to compare qualitatively the influence of the yield strength, heat conductivity, specific heat capacity, Young''s modulus, coefficient of thermal expansion, density and Poisson ratio on the peak welding residual stress.The result shows that the change of yield strength and heat conductivity is wide, which have greater effects on the peak welding residual stress.Whereas, specific heat capacity, Young''s modulus, coefficient of thermal expansion and density show little influence on it.The change of Poisson ratio is close to that of thermal expansion and density, however, its influence is little.The simulation results of welding longitudinal residual stress were verified with cutting pieces stress relieving method for the flat plates with such material properties as 2A12-T4 aluminum alloy.The results have good agreement with tested results, which prove the validity of the simulation results.