韧性断裂准则参数的3种不同标定方法

Three calibration methods for ductile fracture criterion parameters

韧性断裂准则可用于金属塑性成形过程中韧性断裂的判据,但预测的准确性依赖于准则参数的有效标定。在目前常用的基于试验与模拟的反求分析法以及曲面拟合法的基础上,给出了一种断裂阈值积分求解的标定方法。利用一系列宽应力三轴度范围内的试验结果,分别采用上述3种标定方法进行了L-H韧性断裂准则的参数求解,并对3种标定方法进行了对比分析,给出了各自的优缺点。由对比结果可知:相比于反求分析法,断裂阈值积分求解的标定方法和曲面拟合法可以改善求解效率;损伤阈值积分求解的标定方法相比于曲面拟合法而言,精度有所提高。

Ductile fracture criterion is generally used to predict ductile fracture in metal forming process, however its accuracy significantly relays on the calibration of parameters. According to the commonly used inverse analysis and surface fitting by experimental and numerical method, a new calibration method based on the integral of fracture threshold value was proposed. Then, from a series of experimental results of the wide range of stress triaxiality and by applying the three calibration methods above, parameters of L - H ductile fracture criterion were solved. Finally, a comparison of the three calibration methods above were performed, and their advantages and disadvantages were given respectively. Contrast to the normal inverse analysis method, the comparison results show that the calibration method of integral of fracture threshold value and surface fitting method can improve computing efficiency. Meanwhile, the new method can provide a more accurate prediction of fracture than the surface fitting method.