搅拌摩擦焊过程热-力-流全耦合仿真:不同本构方程的仿真效果对比OACSTPCD

The constitutive equation is a crucial component of the fully coupled thermal-mechanical-flow simulation model for the friction stir welding(FSW)process.This paper conducts a fully coupled thermal-mechanical-flow simulation analy-sis of the FSW process for 6mm thick aluminum alloy 6061-T6 plates.To analyze the impact of the form of the constitutive equation on the simulation results,the Chen-Liu constitutive model,the Sellars-Tegart model,and the Johnson-Cook model were used in the simulation,and their results were compared.The simulation results show that the FSW temperature field and flow field calculated by the Chen-Liu model aligned more closely with experimental results than those calculated by the Sellars-Tegart model and the Johnson-Cook model.The reason was that under the temperature conditions near the tool-workpiece interface,the Sellars-Tegart model and the Johnson-Cook model predicted higher flow stresses,making material flow difficult.As a result,the interface state between the tool and the workpiece was primarily sliding friction.In contrast,the Chen-Liu model accurately reflected the rapid softening of the material as the temperature increases.Under the tempera-ture conditions near the tool-workpiece interface,the shear flow stress of the material was lower than the friction stress at the tool/workpiece interface.Consequently,the workpiece undergoes plastic flow due to friction,reducing the sliding friction speed between the tool and the workpiece.This reduction in sliding friction heat generation was greater than the additional heat generated by the plastic flow of the workpiece,resulting in a lower predicted welding temperature using the Chen-Liu model.Overall,the influence of the material constitutive model on the FSW process's temperature field and material flow ve-locity field is due to the fully coupled thermal-mechanical-flow effects of FSW.