基于相变诱导塑性Satoh试验的有限元模拟

Finite element simulation of Satoh test taking into account transformation induced plasticity

通过将相变诱导塑性应变增量引入到总应变增量的分解式中,建立了温度-组织-应力耦合计算的有限元模型。在此基础上,以9Cr1Mo钢作为研究对象,对其Sa-toh试验进行了有限元模拟,对温度-组织-应力耦合计算以及传统的热弹塑性计算结果进行了对比分析。结果表明,无论在应力的演变上,还是在残余应力水平上,两种计算得到的结果均存在较大差异。由于忽略相变的影响,热弹塑性计算得到的结果无法反映在相变过程中所发生的应力"松弛"现象,与实际结果偏差较大。准确地对焊接应力应变进行预测,需要通过温度-组织-应力耦合考虑相变的影响。

By including the increment of transformation-induced plastic strain into the additive decomposition of the increment of total strain, the constitutive equations for thermal-mechano-metallurgic coupled analysis are founded. On the basis of these equations, Satoh test of 9Cr1Mo steel is simulated by using finite element method. The calculated results from thermal-mechano-metallurgical coupled simulation and thermo-elastoplastic simulation are compared and analyzed. It can be found that the evolution of stress and residual stress level calculated by two methods are both different. Due to ignoring the effect of phase transformation, the phenomenon of stress release that has been observed in experiments can not be predicted in the simulated result from thermo-elastoplastic calculation. To calculate stress state in welding accurately, thermo-mechano-metallurgical coupled analysis should be made, and the effect of phase transformation should be taken into account.