Probabilistic modeling of fiber–matrix interface stresses in short-fiber 3D printed composites using effective field methods

This study presents a novel probabilistic modeling approach to investigate the impact of interfacial damage between fibers and the matrix on 3D-printed composites. The approach employs effective field methods (EFM) and Weibull statistics and considers an elastoplastic matrix reinforced with short fibers. A new formulation is developed to compute normal and shear interface stresses using the internal stress of each fiber, which is modeled as an ellipsoid with various aspect ratios. The approach is applied to 3D-printed PLA reinforced with short basalt fibers and compared to literature experiments. The results demonstrate that the proposed approach can aid in understanding interfacial damage and explain the progressive softening of the stress–strain response of composite structures.