Investigation of strain rate sensitivity of Gum Metal under tension using digital image correlation
Investigation of strain rate sensitivity of Gum Metal under tension using digital image correlation
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DOI：
10.1007/s43452-020-00055-9
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发表时间：
2020-05-08
影响因子：
4.4
通讯作者：
Kuramoto, Shigeru
中科院分区：
文献类型：
--
作者：
Golasinski, Karol;Pieczyska, Elzbieta;Kuramoto, Shigeru
通过不同应变率下的拉伸试验，并应用数字图像相关技术（DIC），研究了一种多功能钛合金Gum Metal的力学行为。应力-应变曲线证实了低杨氏模量和高强度的合金。屈服强度的测定值有增加的趋势，而试样断裂伸长率有下降的趋势，随着应变速率的增加。使用放置在应变局部化区域的选定长度的虚拟引伸计（VE）分析真实应力-应变曲线。当VE的初始长度与标距长度相同时，在较低的应变速率下宏观上观察到加工硬化，并且在较高的应变速率下观察到软化。然而，软化效果没有观察到在较短的VE长度。Hencky应变和速率的变形张量分量场的演变进行了分析，在选定的阶段的胶金属加载的各种应变速率。DIC分析表明，对于较低的应变率，变形在宏观上是均匀的，直到较高的平均亨基应变，而对于较高的应变率，应变局部化发生在变形过程的较低平均亨基应变处，并且发生在较小的区域。结果还发现，对于所有的应变速率施加，Hencky应变的最大值的橡胶金属样品破裂前是类似的每个施加的应变速率，和最大的局部值的变形率是两个订单时，相比，施加的平均应变速率值。
Mechanical behavior of a multifunctional titanium alloy Gum Metal was investigated by conducting tensile tests at various strain rates and applying digital image correlation (DIC) technique. Stress-strain curves confirmed low Young's modulus and high strength of the alloy. The determined values of yield strength had a tendency to increase, whereas the elongation to the specimen rupture tended to decrease with increasing strain rate. True stress versus strain curves were analyzed using selected lengths of virtual extensometer (VE) placed in the strain localization area. When the initial length of the VE was the same as the gauge length, work hardening was observed macroscopically at lower strain rates, and a softening was seen at higher strain rates. However, the softening effect was not observed at the shorter VE lengths. Evolution of the Hencky strain and rate of deformation tensor component fields were analyzed for various strain rates at selected stages of Gum Metal loading. The DIC analysis demonstrated that for lower strain rates the deformation is macroscopically uniform up to the higher average Hencky strains, whereas for higher strain rates the strain localization occurs at the lower average Hencky strains of the deformation process and takes place in the smaller area. It was also found that for all strain rates applied, the maximal values of Hencky strain immediately before rupture of Gum Metal samples were similar for each of the applied strain rates, and the maximal local values of deformation rate were two orders higher when compared to applied average strain rate values.