论文部分内容阅读
不同温度下的薄壁钛管剪应力本构参数识别,是研究薄壁钛管差温剪切弯曲过程管材塑性变形行为迫切需要解决的关键问题。提出了一种管材剪切测试的方法。将不同温度下薄壁钛管等温剪切测试、剪切测试过程模拟有限元模型、以及基于距离函数的响应面模型相结合,提出了薄壁钛管不同温度下剪应力本构参数逆向识别方法。采用该方法,识别了TA2薄壁钛管剪应力本构参数。同时建立了TA2薄壁钛管差温剪切弯曲过程模拟3维弹塑性热力耦合有限元模型。分别采用剪应力本构参数和单拉应力本构参数模拟弯管实验过程,评估了有限元模型的可靠性。结果表明:对于剪应力本构参数,温度越高,管材的K值和n值将减小,m值呈现波动的趋势。与单拉应力本构参数相比,剪应力本构参数对温度的变化更敏感,且剪应力本构参数值较小。与单拉应力本构参数相比,使用剪应力本构参数的有限元模型精度较高,模拟精度最大提高了60%。
The identification of constitutive parameters of shear stress of thin-walled titanium tube at different temperatures is a key issue that needs to be solved in order to study the plastic deformation behavior of thin-walled titanium tube during the process of temperature-shear deformation. A method of pipe shear test is proposed. The isothermal shear tests of thin-walled titanium tubes at different temperatures, the simulation finite element model of the shear test process and the response surface model based on the distance function were combined to propose a reverse identification method of the constitutive parameters of shear stress at different temperatures of thin-walled titanium tubes . Using this method, the constitutive parameters of TA2 thin-walled titanium tube are identified. At the same time, a 3-D elasto-plastic coupled thermo-mechanical finite element model of TA2 thin-walled titanium tube under differential temperature shear bending was established. The shear bending constitutive parameters were simulated by shear stress constitutive parameters and single tensile stress constitutive parameters respectively to evaluate the reliability of the finite element model. The results show that for the constitutive parameters of shear stress, the higher the temperature is, the lower the value of K and n and the value of m tend to fluctuate. Compared with the constitutive parameters of single tensile stress, the constitutive parameters of shear stress are more sensitive to the change of temperature and the constitutive parameters of shear stress are smaller. Compared with the constitutive parameters of single tensile stress, the finite element model using constitutive parameters of shear stress has a higher precision and the maximum accuracy of simulation is improved by 60%.