Abstract We subjected a commercial dental composite formed by interconnecting polymer-ceramic scaffolds to extensive quasi-static, static and cyclic experiments under biaxial flexure. By this we meant to obtain static and cyclic subcritical crack growth exponents that, based on established relationships describing the degradation of frictional bridging mechanisms, challenging the notion of a suggested R-curve behavior. By exploring the fracture statistics of specimens with increasing effective volumes and effective areas, we demonstrated the presence of a bi-modal defect size distribution in disaccord with the Weibull behavior across length scales. Lifetime distributions seemed to follow the strength distributions, and were used to derive crack growth velocity diagrams for combined levels of applied stress. Ultimately, the claim of an R-curve behavior could not be supported based on the absence of any significant cyclic fatigue effect, i.e. bridging degradation.

中文翻译：

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亚临界条件下生物医学聚合物-陶瓷互穿支架复合材料的裂纹扩展行为

摘要 我们对通过互连聚合物-陶瓷支架形成的商用牙科复合材料进行了双轴弯曲下的大量准静态、静态和循环实验。我们的目的是获得静态和循环亚临界裂纹扩展指数，这些指数基于描述摩擦桥接机制退化的既定关系，挑战建议的 R 曲线行为的概念。通过探索具有增加的有效体积和有效面积的试样的断裂统计数据，我们证明了双峰缺陷尺寸分布的存在与长度尺度上的威布尔行为不一致。寿命分布似乎遵循强度分布，并用于推导出应用应力组合水平的裂纹扩展速度图。最终，