材料的锯齿屈服效应以及低应变水平下塑性应变比r值应变路径存在的奇异性会造成r值测试结果的明显离散，给材料性能的准确评价带来较大的困难，而区间r值可以较好地解决该类离散问题，在结果的重复性方面显现出独特优势。在区间r值的计算过程中，宽度和长度方向的真塑性应变εb和εL线性回归后得到的直线是否强制通过坐标原点，会导致部分测试结果的差异，但大部分情况下该差异并不显著，仅就重复性而言，目前无法确认是否应该设置边界条件。

Both the serrated yielding of materials and singularity of the strain path in low strain level would cause discreteness of plastic stain ratio r value, and it would be hard to accurately evaluate the property of materials. The interval r value was a good solution for this problem due to its unique advantage of the result reproducibility. During the calculation of interval r value, whether or not the εb-εL regression line passed through the origin point of the coordinate would lead to the difference in results, but the difference was not obvious in most condition. Whether or not the boundary condition of interval r value calculation should be set hadn’t been confirmed as far as the reproducibility.