Engineering elastic constants and strength parameters shall be known to the designer in order to predict the structural response of composite materials. These properties shall be determined in various directions as per the designated standards. Testing of composite materials under the combined effect of in-plane shear and normal stress is of great importance. In this work, a new Arcan fixture has been designed, and then manufactured from aluminum alloy AA7075-T73. This test fixture can be used for uniaxial as well as biaxial testing of fiber reinforced polymers (FRPs) laminates in pure shear, and combined normal/shear stress states. Nevertheless, the fixture can be used for other materials where combined in-plane testing is required including metals and polymers. The special butterfly shape Arcan specimen was optimized based on the parametric study in ABAQUS environment by a Python scripting. The objective of the parametric study was to get a uniform shear stress field in the notch section of the specimen which is the cross-sectional area between the two opposite V-notch roots. The domain of the uniform shear stress-strain distribution in the notch section must be greater enough than the size of the strain gauge rosettes where these can be effectively installed for strain acquisition. The experimental set-ups for the realization of pure shear stress, normal stress, and combined normal/shear stress scenarios are schematically elaborated. The pure shear stress-strain response based on the Arcan test was compared with the tensile testing of ±45 0 symmetric laminate.

中文翻译：

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用于纤维增强聚合物复合材料的平面纯剪切和组合法向/剪切应力表征的新型 Arcan 夹具设计

设计者应了解工程弹性常数和强度参数，以便预测复合材料的结构响应。这些特性应按照指定标准在各个方向上确定。在面内剪切和正应力的共同作用下对复合材料进行测试非常重要。在这项工作中，设计了一个新的 Arcan 夹具，然后由铝合金 AA7075-T73 制造。该测试夹具可用于在纯剪切和组合法向/剪切应力状态下对纤维增强聚合物 (FRP) 层压板进行单轴和双轴测试。然而，该夹具可用于需要组合面内测试的其他材料，包括金属和聚合物。特殊的蝴蝶形状 Arcan 标本基于 ABAQUS 环境中的参数研究通过 Python 脚本进行了优化。参数研究的目的是在试样的缺口部分获得均匀的剪切应力场，即两个相对的 V 型缺口根部之间的横截面面积。凹口部分中均匀剪切应力-应变分布的域必须足够大于应变仪花环的尺寸，在那里可以有效地安装这些花环以获取应变。示意性地阐述了实现纯剪应力、正应力和组合正应力/剪应力场景的实验装置。将基于 Arcan 测试的纯剪切应力-应变响应与 ±45 0 对称层压板的拉伸测试进行比较。