theoretical and experimental standardization of strain hardening index in tensile deformation
theoretical and experimental standardization of strain hardening index in tensile deformation
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DOI：
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发表时间：
2006-07
影响因子：
2.3
通讯作者：
Song Yu-quan;Guan Zhiping;Ma Pinkui;Song Jiawang
中科院分区：
文献类型：
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作者：
Song Yu-quan;Guan Zhiping;Ma Pinkui;Song Jiawang
基于应力是应变和应变率函数的状态方程，推导了超塑性拉伸变形时的微分本构方程，并解释了该方程中应变硬化指标的力学意义。推导了应变硬化指标的约束方程，定义了典型变形路径下的应变硬化指标，得到了它们之间的相互关系。结合数值模拟，推导了测量公式、典型变形路径指标及精确测量方法。在此基础上，对应变硬化指标进行了实验测量，并对测量方法的结果进行了详细分析。结果表明：应变硬化指数是非恒定的，与应变和变形路径的变化规律密切相关；在给定的变形路径下，应变硬化指数也与所采用的测量公式密切相关。因此，在引用应变硬化指标时，应清楚地显示相应的变形路径；在测量应变硬化指标时，所采用的公式应与变形路径相对应。
Based on the state equation that stress is a function of strain and strain-rate, the differential constitutive equation during superplastic tensile deformation is deduced, and then the mechanical meaning of the strain hardening index in the equation is interpreted. The constraint equation of strain hardening index is deduced, the strain hardening indexes in typical deformation paths are defined, and their interrelations are obtained. The formulae for measuring, indexes in typical deformation paths and precise measuring methods combined with numerical simulation are deduced. According to them, strain hardening indexes are experimentally measured, and measuring methods results are elaborately analyzed. The results proved that the strain hardening index is non-constant, and has close relations to the changing rule of strain and deformation path; strain hardening index has also close relations to the also with adopted measuring formula in the given deformation path. Therefore, as strain hardening index is quoted, the corresponding deformation path should be shown clearly; when measuring strain hardening index, the adopted formula should correspond to deformation path.