Abstract Fracture modes I and II interact in mixed-mode loading conditions, and the interaction is typically taken into account using a mixed-mode fracture criterion. In this work, a concept for defining the criterion is developed through an experimental-numerical simulation analysis. The mixed-mode behaviour for the criterion is tested and analysed with a single specimen design. The design of the specimen simplifies the measurement when complex test arrangements and preparations for various specimen geometries are excluded in practice. Here, the mixed-mode fracture behaviour of the specimen is analysed in detail using digital image correlation (DIC). The DIC data are used in collaboration with a finite element–based crack onset analysis, including the virtual crack closure technique, in order to consider the typical simplifications and their effects on the mixed-mode criterion. As a benchmark case, the fracture criterion is determined for an epoxy film adhesive FM 300-2 using the developed approach. The developed approach was shown to be feasible and effective for defining the mixed-mode fracture criterion. The determined Power law criterion’s exponents were below unity, which points out that the common (presumed) exponent values in the current literature are actually unconservative.

中文翻译：

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通过单个试样设计定义强韧环氧薄膜粘合剂混合模式行为的概念

摘要 断裂模式 I 和 II 在混合模式加载条件下相互作用，通常使用混合模式断裂准则来考虑相互作用。在这项工作中，定义标准的概念是通过实验数字模拟分析开发的。该准则的混合模式行为是通过单个样本设计进行测试和分析的。当在实践中排除了针对各种试样几何形状的复杂测试安排和准备工作时，试样的设计简化了测量。在这里，使用数字图像相关 (DIC) 详细分析了试样的混合模式断裂行为。DIC 数据与基于有限元的裂纹开始分析结合使用，包括虚拟裂纹闭合技术，为了考虑典型的简化及其对混合模式标准的影响。作为基准案例，使用开发的方法确定环氧树脂薄膜粘合剂 FM 300-2 的断裂标准。所开发的方法被证明对于定义混合模式断裂标准是可行和有效的。确定的幂律标准的指数低于统一值，这表明当前文献中常见的（假定的）指数值实际上是不保守的。