Modeling and simulating interfacial shear load transfer in fiber-reinforced composites is crucial for characterizing fiber pullout behaviors. Addressing this complicated topic, this work presents a novel phase-field framework to simulate interfacial failure behaviors in fiber-reinforced cementitious composites. Specifically, a comprehensive constitutive model is proposed to describe both interfacial debonding and frictional slipping, which accounts for snubbing and bonding effects in fiber-reinforced composites. The developed model has the following novel features: (1) The model can simultaneously characterize interfacial debonding and frictional slipping, and thus thoroughly describe the fiber-reinforcing mechanisms in quasi-brittle solids; (2) An interfacial slipping degradation theory is implemented in the model to describe interfacial slippage and stress degradation during slipping; and (3) The model effectively and precisely incorporates the friction law with interface normal vectors. The developed model is successfully validated against experimental and simulated results. Finally, a series of parameter studies are undertaken to provide strategic insights to improve the mechanical properties of the composites. The proposed method adds efficiency and robustness to the study of features and fracture mechanisms of fiber reinforcements in complex fiber–cement systems.

对纤维增强复合材料中的界面剪切载荷传递进行建模和仿真对于表征纤维的拉拔行为至关重要。针对这个复杂的主题，这项工作提出了一种新颖的相场框架，可以模拟纤维增强水泥基复合材料中的界面破坏行为。具体而言，提出了一种综合的本构模型来描述两种界面剥离摩擦滑移，这解释了纤维增强复合材料的缓冲和粘结作用。所开发的模型具有以下新颖特征：（1）该模型可以同时表征界面剥离和摩擦滑移，从而详尽地描述了准脆性固体中的纤维增强机理；（2）在模型中采用了界面滑移退化理论来描述滑移过程中的界面滑移和应力退化。（3）该模型有效，精确地将摩擦定律与界面法线向量相结合。针对实验和模拟结果成功验证了开发的模型。最后，进行了一系列参数研究，以提供战略见解以改善机械性能复合材料。所提出的方法为复杂纤维水泥系统中纤维增强材料的特征和断裂机理的研究增加了效率和鲁棒性。