Abstract In this study, for the first time, the load-carrying capacity (LCC) of test specimens containing U-shaped and V-shaped notches made of Al6061-T6 aluminum alloy under combination of out-of-plate shear and tensile loading (mixed mode I/III) is studied. U-notched specimens are made with different notch tip radii and V-notched specimens are made with different notch tip radii and notch opening angles. At first, the specimens are subjected to different mixed mode I/III loading conditions using a universal tension-compression loading device and their LCCs are measured experimentally. Then, considering the ductile behavior of the material under investigation, it is attempted to use the Equivalent Material Concept (EMC) in theoretical analysis, since it does not require complex and time-consuming elastic-plastic analyses. Initial evidence for the combination of the EMC with the brittle fracture criteria of point stress (PS) and mean stress (MS) indicates that both criteria show large errors in predicting the LCC of the test samples. The cause is the large failure strain of the Al6061-T6 alloy. Therefore, a newly developed concept similar to the EMC, called the Fictitious Material Concept (FMC), is applied. Based on the FMC, instead of equalizing the elasticity modulus of the ductile material and the fictitious material, the failure strains of those materials at the ultimate points are assumed to be equal. It is shown that combining the FMC with the PS and MS criteria leads to acceptable predictions of the LCC of the tested specimens.

中文翻译：

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U 型和 V 型缺口 Al6061-T6 板的断裂：在混合模式 I/III 加载下对虚拟材料概念的首次检查

摘要 本研究首次研究了Al6061-T6铝合金制成的U型和V型缺口试样在板外剪切和拉伸载荷组合下的承载能力（LCC）。混合模式 I/III) 进行了研究。U 型缺口试样由不同的缺口尖端半径制成，V 型缺口试样由不同的缺口尖端半径和缺口开口角制成。首先，使用通用拉压加载装置对试样施加不同的混合模式 I/III 加载条件，并通过实验测量它们的 LCC。然后，考虑到所研究材料的延展行为，尝试在理论分析中使用等效材料概念 (EMC)，因为它不需要复杂且耗时的弹塑性分析。将 EMC 与点应力 (PS) 和平均应力 (MS) 的脆性断裂标准相结合的初步证据表明，这两个标准在预测测试样品的 LCC 方面都显示出很大的误差。原因是Al6061-T6合金的失效应变大。因此，应用了一种类似于 EMC 的新开发概念，称为虚拟材料概念 (FMC)。基于 FMC，假设延性材料和虚拟材料的弹性模量不相等，而是假设这些材料在极限点的破坏应变相等。结果表明，将 FMC 与 PS 和 MS 标准相结合，可以对测试样本的 LCC 进行可接受的预测。