硬化模型对Ti80厚板焊接热-力耦合仿真计算的影响OACSTPCD

In the multi-layer and multi pass welding of marine Ti80 titanium alloy thick plates,the material has undergone multiple thermal-stress cycles.The welding joint needs to consider the thermoplastic deformation behavior of the material under cyclic loading,and different plastic constitutive models express quite differences in material mechanical properties.Therefore,the material plastic model has a direct impact on the simulation calculation of welding residual stress.This article obtains the material parameters of the ideal elastic-plastic model,isotropic hardening model,dynamic hardening model,and mixed hardening model of Ti80 titanium alloy material through tensile tests at different temperatures(20℃～900℃)and low cycle fatigue tests at different temperatures(20℃～800℃).Simulate and calculate the welding residual stress of Ti80 welded joints using different hardening models,and measure the residual stress using X-ray.Compare the obtained residual stress results and analyze the influence of different hardening models on welding residual stress.It can be concluded that the ideal plasticity model underestimates the magnitude of residual stress,while the isotropic hardening model slightly overesti-mates the magnitude of residual stress in the molten pool and its vicinity.The residual stress calculation values of the dy-namic hardening model and the mixed hardening model are relatively close,with the former slightly smaller and the latter more accurately predicting residual stress.From the perspective of engineering applications,it is recommended to use an iso-tropic strain hardening model,which has the highest value in residual stress prediction.Using this model can obtain rela-tively conservative prediction values.