The end‐notched flexure (ENF) test is widely used for measuring the Mode II critical strain energy release rate of adhesively bonded joints (ABJs). Unstable crack growth in ENF joints with brittle adhesives is a common phenomenon. Classic data reduction methods like the direct beam theory (DBT) and the compliance‐based beam method (CBBM) usually result in unacceptable scatter when crack grows unstable. In this study, the application of a compliance calibration method (CCM) for ENF adhesive joints with a brittle adhesive is experimentally investigated. For this purpose, ENF specimens were manufactured and tested. Different data reduction methods were considered for treating the results. Afterwards, the obtained fracture energies were used as an input parameter in a finite element (FE) analysis with a cohesive zone model to evaluate the validity of the experimental data. It is shown that the fracture loads obtained by the CCM have the best agreement with the experimental ones comparing with the other data reduction approaches. To study the effect of geometry on the CCM results, ENF specimens with different adhesive thicknesses, substrate thicknesses and span lengths were also considered in this study, and some general conclusions are made about the geometrical parameters effect on the Mode II fracture energy.

中文翻译：

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使用顺应性校准方法表征脆性胶粘剂的II型断裂能

端部弯曲挠曲（ENF）测试广泛用于测量粘合接头（ABJ）的II型临界应变能释放率。脆性胶粘剂在ENF接头中裂纹扩展不稳定是普遍现象。当裂纹变得不稳定时，直接束流理论（DBT）和基于柔量的束流方法（CBBM）等经典的数据减少方法通常会导致不可接受的散射。在这项研究中，对使用脆性胶粘剂的ENF胶粘接头的顺应性校准方法（CCM）的应用进行了实验研究。为此，制造并测试了ENF标本。考虑使用不同的数据缩减方法来处理结果。之后，所获得的断裂能在具有内聚区模型的有限元（FE）分析中用作输入参数，以评估实验数据的有效性。结果表明，与其他数据约简方法相比，CCM获得的断裂载荷与实验值具有最佳的一致性。为了研究几何形状对CCM结果的影响，本研究还考虑了具有不同粘合剂厚度，基底厚度和跨度长度的ENF标本，并得出了几何参数对II型断裂能的影响的一些一般性结论。