Experimental extrapolation of hardening curve for cylindrical specimens via pre-torsion tension tests
Experimental extrapolation of hardening curve for cylindrical specimens via pre-torsion tension tests
复制标题
通过预扭转拉伸试验推断圆柱形试样的硬化曲线
DOI：
10.1177/0309324719887863
复制
发表时间：
2019-11-16
影响因子：
1.6
通讯作者：
Gao, Dan
中科院分区：
文献类型：
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作者：
Chen, Junfu;Guan, Zhiping;Gao, Dan
由常规单轴拉伸试验确定的圆柱形试件的硬化曲线通常对应于由于颈缩的发生而产生的相对较窄的应变范围。为了获得大应变范围内的硬化曲线，本研究通过由不同预扭应变的圆柱体试件的应力-应变数据外推硬化曲线，建立了多试件预扭拉伸试验。在进行多试件拉伸试验时，需要解决扭转试件预应变的计算问题。提出了多试件拉伸试验的三种计算方法，得出了Q345试件各自的硬化曲线。通过与单试件拉伸试验的反推方法的比较，提出了多试件预扭试验的优化策略。对Q345试件的试验结果表明，多试件拉伸试验测得的硬化曲线的应变范围(0-0.6)明显大于常规拉伸试验的应变范围(0-0.04)，具有较高的精度。与目前的预挤拉多试件试验相比，本文提出的预扭多试件试验具有更强的适用性和通用性，成本更低，效率更高。
The hardening curve for cylindrical specimens determined by conventional uniaxial tension tests generally corresponds to a relatively narrow strain range due to the occurrence of necking. To achieve the hardening curve within a large strain range, in this study, the multi-specimen tension tests with pre-torsion are developed through extrapolating the hardening curve from the stress–strain data of cylindrical specimens with various magnitudes of pre-torsion strains. The calculation of pre-strain of twisted specimen needs to be addressed for the multi-specimen tension tests. The three calculation methods on the multi-specimen tension tests are proposed, leading to their individual hardening curves for Q345 specimens. An optimal strategy for the multi-specimen tests with pre-torsion is presented by comparison with the inverse method for a single specimen tension test. The results for Q345 specimen show the strain range (0–0.6) of the hardening curve determined by the multi-specimen tension tests is significantly larger than one (0–0.04) from conventional tension test, with reasonable accuracy. Compared with the current multi-specimen tests with pre-extrusion/drawing, the proposed multi-specimen tests with pre-torsion is possessed of stronger applicability and generality, lower cost, and higher efficiency.