Stress Correction Method for Flow Stress Identification by Tensile Test using Notched Round Bar
Stress Correction Method for Flow Stress Identification by Tensile Test using Notched Round Bar
复制标题
DOI：
10.9773/sosei.57.977
复制
发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Masanobu Murata;T. Nishiwaki;Y. Yoshida
中科院分区：
文献类型：
--
作者：
Masanobu Murata;T. Nishiwaki;Y. Yoshida
本文提出了用缺口圆杆拉伸试验识别流动应力的应力修正方法。流动应力是在均匀伸长率和局部伸长率，直到最终断裂的拉伸试验与圆周缺口圆棒拉伸试样进行评估。通过图像分析测量拉伸载荷和缺口形状的变化。为了将平均拉应力修正为流变应力，对拉伸试验进行了反分析。为了验证反分析的正确性，采用有限元法进行了数值拉伸试验。通过对数值拉伸试验的反分析，修正后的流变应力完全再现了由Swift和Voce定律确定的两种参考流变应力曲线。另一方面，通过Bridgman方法（其是常规的应力校正方法）校正的流动应力高估了这些参考流动应力曲线。在低碳钢SS400（JIS）的实际拉伸试验的情况下，通过逆分析校正的流动应力对应于在均匀伸长率下确定的斯威夫特定律。与数值拉伸试验结果相比，Bridgman法修正后的流变应力值要高于反分析结果。
Abstract In this paper, a stress correction method for flow stress identification using notched round bar tensile test is proposed. Flow stress is evaluated in uniform elongation and local elongation until final fracture in a tensile test with circumference notched round bar tensile test specimens. Tensile load and change in the shape of the notch are measured by image analysis. In order to correct the average tensile stress to the flow stress, inverse analysis is applied to the tensile test. For the validation of the inverse analysis, numerical tensile tests are performed by FEM. As a result of applying the inverse analysis for the numerical tensile tests, the corrected flow stress completely reproduces the two types of reference flow stress curves which are determined by Swift’s and Voce’s law. On the other hand, the flow stress corrected by Bridgman’s method, which is a conventional stress correction method, overestimated these reference flow stress curves. In the case of the actual tensile test of low carbon steel SS400 (in JIS), the flow stress corrected by inverse analysis corresponds to Swift’s law determined in uniform elongation. As well as numerical tensile test results, the flow stress corrected by Bridgman’s method is higher than that of obtained by the inverse analysis.