Numerical studies of crack propagation in composites reinforced by irregular particles

Abstract

The study of crack-particle interaction and its impact on a material's fracture toughness are important investigations in composite materials. The micromechanical deformations that occur in the area of the embedded particles can lead to crack initiation and affect the overall macroscopic properties. It is a known fact that in composites with stiff brittle particles and weak plastic matrix, during the process of tensile deformation, microcracks are first formed at the defects and weak interfaces. Many such fine cracks converge to form large cracks leading to the fracture propagation on the particle-matrix boundary and in the matrix. Crack propagation in particle-reinforced composites can be significantly influenced by parameters such as particle size, geometry, distribution, and interface to the surrounding matrix. This article studies the effect of these parameters on crack initiation and growth by simulating various 2D models of uniaxial tensile tests through finite element modeling. A typical part of a tensile test specimen is used for 2D modeling. It is observed that the irregular shape of the particles plays a crucial role in the crack propagation and trajectory of the crack path, as particles with sharp corners that are oriented perpendicular to the tensile loading define the sites of stress concentration, which eventually leads to the crack formation. Furthermore, the irregular particles are approximated by circular and elliptical shapes with the same surface area. The tangential behavior between the particles and the matrix has been modeled as zero friction. Finally, the tensile strengths for different microstructure realizations have been evaluated in this study.