Abstract We present a computational framework to explore the effect of microstructure and constituent properties upon the fracture toughness of fibre-reinforced polymer composites. To capture microscopic matrix cracking and fibre-matrix debonding, the framework couples a phase field fracture method and a cohesive zone model in the context of the finite element method. Virtual single-notched three point bending tests on fibre reinforced composites are conducted. The actual microstructure of the composite is simulated by an embedded cell in the fracture process zone, while the remaining area is homogenised to be an anisotropic elastic solid. A detailed comparison of the predicted results with experimental observations reveals that it is possible to accurately capture the crack path, interface debonding and load versus displacement response. The sensitivity of the crack growth resistance curve (R-curve) to the matrix fracture toughness and the fibre-matrix interface properties is determined. The influence of porosity upon the R-curve of fibre-reinforced composites is also explored, revealing a higher crack growth resistance with increasing void volume fraction. These results shed light into microscopic fracture mechanisms and set the basis for efficient design of high fracture toughness composites.

中文翻译：

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纤维增强复合材料微观断裂和R曲线行为的相场预测

摘要 我们提出了一个计算框架来探索微观结构和成分特性对纤维增强聚合物复合材料的断裂韧性的影响。为了捕捉微观基体开裂和纤维-基体脱粘，该框架在有限元方法的背景下结合了相场断裂方法和内聚区模型。对纤维增强复合材料进行了虚拟单缺口三点弯曲试验。复合材料的实际微观结构由断裂过程区中的嵌入式单元模拟，而其余区域均化为各向异性弹性固体。预测结果与实验观察的详细比较表明，可以准确捕获裂纹路径、界面脱粘和载荷与位移响应。确定裂纹扩展阻力曲线（R 曲线）对基体断裂韧性和纤维-基体界面特性的敏感性。还探讨了孔隙率对纤维增强复合材料 R 曲线的影响，表明随着空隙体积分数的增加，抗裂纹扩展性更高。这些结果揭示了微观断裂机制，并为高断​​裂韧性复合材料的有效设计奠定了基础。