面向切削加工的Johnson-Cook本构参数识别方法研究

Methodology of identification of Johnson-Cook constitutive parameters for cutting processes

为了获得钛合金Ti6Al4V面向切削加工过程的Johnson-Cook模型参数,基于Oxley切削模型和自由正交切削实验资料,以主剪切区材料为研究对象,分别计算了剪切面上的剪切流动应力和剪应力。采用最小二乘原理将参数识别问题转化为以JC模型参数为未知量,以这两个应力差值的平方和为函数,以该函数的最小值为目标的优化问题,在合适的边界条件下,采用遗传算法搜索该优化问题的全局最优解,进而求得对应的本构常数。最后,用有限元仿真模型验证了本文所提本构参数识别方法的合理性及所得结果的正确性。

In order to obtain the Johnson-Cook（JC）constitutive constants of titanium alloy Ti6Al4 Vfor cutting processes,based on Oxley cutting theory and the free orthogonal cutting experiment data,the shear flow stress and shear stress on the shearing surface for the material in primary shear zone were calculated respectively in this paper.The issue of parameter identification was transferred into the problem of function optimization which took JC model parameters as the unknowns,the sum of squares of the difference of those two kinds of stress as the function,and the minimum of the function as the objective.The genetic algorithm was used to solve the issue of function optimization with appropriate boundary conditions,and then the constitutive constants were obtained.In the end,finite element simulation model was used to validate the rationality of the methodology of this paper and the correctness of the results.