Abstract Dynamic material characterization is one of important factors in the development of modern transportation industry to overcome two main challenges, i.e. lightweight and crashworthy vehicles. The most commonly used apparatus to characterize the material in high strain rates is the Hopkinson bar. The Hopkinson bar can be conducted into several loading conditions such as compression, tension, shear, torsion and multiaxial. This paper focuses on the split Hopkinson shear bar testing, especially on the effect of the shear angles on generating the shear stress – shear strain curves, shear strain rates, and final shear strains. Four geometries of specimen were studied, i.e. circular hat-shaped (CHS), flat hat-shaped (FHS), punch (P) and double-notch (DN). This research is conducted with three main considerations, i.e. the same kinetic energy (7.34 Joule), the same shear area (±25 mm2), and the shear angles were varied as ±2.5°, 5°, 7.5°, 10° and 15°. This study shows that each testing has its own advantages and disadvantages and they generate different strain rate, strain rate gradient, final strain, and shear stress – shear strain relations which is not desirable. In term of shear angles, authors recommend using a shear angle of ± 5°. This shear angle generates the best purity on the shear loading among other tests and also the flow stress variation (among four tests) are quite acceptable ±16.4%.

中文翻译：

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剪切角对分体式霍普金森剪切杆试验的影响

摘要 动态材料表征是现代交通运输业发展的重要因素之一，以克服车辆轻量化和耐撞性两大挑战。在高应变率下表征材料的最常用设备是霍普金森棒。霍普金森杆可以承受多种载荷条件，例如压缩、拉伸、剪切、扭转和多轴。本文重点介绍拆分霍普金森剪力杆测试，特别是剪切角对产生剪应力的影响——剪应变曲线、剪应变率和最终剪应变。研究了四种几何形状的试样，即圆形帽形（CHS）、平帽形（FHS）、冲头（P）和双缺口（DN）。这项研究是在三个主要考虑因素下进行的，即相同的动能 (7. 34 焦耳)，相同的剪切面积 (±25 mm2)，剪切角变化为 ±2.5°、5°、7.5°、10° 和 15°。这项研究表明，每种测试都有其自身的优点和缺点，它们会产生不同的应变率、应变率梯度、最终应变和剪应力 - 剪应变关系，这是不可取的。在剪切角方面，作者建议使用 ± 5° 的剪切角。在其他测试中，该剪切角在剪切载荷上产生最佳纯度，并且流变应力变化（在四个测试中）是完全可以接受的 ±16.4%。和剪应力 - 剪应变关系，这是不可取的。在剪切角方面，作者建议使用 ± 5° 的剪切角。在其他测试中，该剪切角在剪切载荷上产生最佳纯度，并且流变应力变化（在四个测试中）是完全可以接受的 ±16.4%。和剪应力 - 剪应变关系，这是不可取的。在剪切角方面，作者建议使用 ± 5° 的剪切角。在其他测试中，该剪切角在剪切载荷上产生最佳纯度，并且流变应力变化（在四个测试中）是完全可以接受的 ±16.4%。