论文标题
复合材料微观桥接行为的相位场断裂预测
Phase field fracture predictions of microscopic bridging behaviour of composite materials
论文作者
论文摘要
我们研究了微结构桥梁对复合材料断裂韧性的作用。为了实现这一目标，提出了一个新的计算框架，该框架集成了相位场断裂和凝聚区模型，以模拟纤维断裂，基质裂纹和纤维 - 矩阵脱键蛋白。复合微结构由裂纹尖端附近的嵌入式细胞表示，而样品的其余部分被建模为各向异性弹性固体。首先，根据单不正的三分弯曲测试的横向基质破裂的实验数据进行了验证。然后，扩展该模型以预测晶粒桥梁，实体微结构和3D纤维桥对裂纹生长抗性的影响。结果表明，这些微观结构在通过纤维 - 矩阵脱发，纤维断裂和裂纹偏转方面非常有效地增强断裂韧性。特别是，相对于散装基质的3D纤维桥接效应可以将失败时消散的能量增加三个数量级以上。远远超过了从混合物规则获得的预测。这些结果阐明了微观桥接机制，并为开发高断裂韧性复合材料提供了虚拟工具。
We investigate the role of microstructural bridging on the fracture toughness of composite materials. To achieve this, a new computational framework is presented that integrates phase field fracture and cohesive zone models to simulate fibre breakage, matrix cracking and fibre-matrix debonding. The composite microstructure is represented by an embedded cell at the vicinity of the crack tip, whilst the rest of the sample is modelled as an anisotropic elastic solid. The model is first validated against experimental data of transverse matrix cracking from single-notched three-point bending tests. Then, the model is extended to predict the influence of grain bridging, brick-and-mortar microstructure and 3D fibre bridging on crack growth resistance. The results show that these microstructures are very efficient in enhancing the fracture toughness via fibre-matrix debonding, fibre breakage and crack deflection. In particular, the 3D fibre bridging effect can increase the energy dissipated at failure by more than three orders of magnitude, relative to that of the bulk matrix; well in excess of the predictions obtained from the rule of mixtures. These results shed light on microscopic bridging mechanisms and provide a virtual tool for developing high fracture toughness composites.
