This paper examines the fracture of AA6061‐T6 specimens with ductile behavior having notches with keyhole geometry under combined loading of tension/torsion. The investigation is performed by theoretical and experimental methods. New fracture tests are performed using a loading fixture on the samples made of AA6061‐T6 weakened by keyhole notches with different notch tip radii. For theoretically estimating the onset of fracture in the tested notched specimens, a concept called “Fictitious Material Concept (FMC)” is used to equate the ductile material with a fictitious brittle material. Therefore, use of this concept allows use of the linear elastic brittle fracture criteria for ductile materials. The brittle fracture criteria utilized are the “mean stress (MS)” and “maximum tangential stress (MTS)” criteria. The small difference between the theoretical and experimental results confirms that use of the combination of FMC with the two criteria is successful in predicting failure of the keyhole notched AA6061‐T6 samples.

中文翻译：

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关于使用虚拟材料概念来估计大拉扭变形下钥匙孔缺口AA6061-T6试样的极限载荷

本文研究了具有拉伸性能的AA6061-T6标本的断裂，这些标本具有在键合/拉伸组合载荷下具有锁眼形状的缺口。该调查是通过理论和实验方法进行的。使用加载夹具对由Aa6061-T6制成的样品进行了新的断裂测试，该样品被具有不同缺口尖端半径的锁孔缺口削弱了。为了从理论上估计测试的缺口试样中的断裂发生，使用了一种称为“虚拟材料概念（FMC）”的概念来将可延展材料与虚拟脆性材料等同起来。因此，使用此概念可将线性弹性脆性断裂标准用于延性材料。使用的脆性断裂标准是“平均应力（MS）”和“最大切向应力（MTS）”标准。