一种求解双曲线本构方程中材料常数的方法

An approach to determine material constants of hyperbolic sine constitutive equation

基于单参数非线性最小平方法,提出了一种优化求解双曲线本构方程中表观激活能和其他材料常数的方法。利用热压缩试验获得的热变形流变应力数据,采用该方法得到了T122和T91耐热钢不同应力水平的表观激活能和其他材料常数,确定材料常数后的双曲线方程所预测的流变应力与试验值符合很好,表明该方法可方便准确求解热变形激活能和其他材料常数,且确定材料常数后的双曲线本构方程能够应用于计算不同应变速率和温度下的热变形流变应力。根据双曲线正弦函数的定义,建立了T122钢和T91钢热变形条件下流变应力双曲线本构方程的显式表达式。

An accurate and simple computational method was developed to determine the apparent activation energy and material parameters of the hyperbolic sine constitutive equation based on one parameter nonlinear least squares regression.The proposed method was applied to obtain the apparent activation energy and material constants of T122 and T91 steels together with obtained hot compression data. A good agreement between experimental data and predicted ones was achieved,which indicated that the proposed method was applicable to predict flow stress under hot deformation. According to the definition of hyperbolic sine, flow stress constitutive equations of T122 and T91 steels had been developed.