An Experimental and Numerical Investigation of Particle Morphology Effect on the Elasto-plastic Behavior of Particle-filled Composites

In this study, the influence of particle shapes on the elastoplastic response of composite materials is investigated both experimentally and computationally. Flake, spherical, irregular, and rod type glass particles are used as filler in the epoxy matrix material in various mass fractions: 5, 10, 15 %. For each investigated composite material, mechanical properties such as elastic modulus, tensile strength, and tensile fracture strain are determined by experimentally obtained stress-strain curves. Flake and irregular particle types give the maximum and minimum elastic modulus values, respectively. The addition of glass particles has an adverse effect on the tensile strength and tensile fracture strain. The worst filling types in terms of tensile strength and tensile fracture strain are the flake and the irregular ones due to the stress concentrations at the sharp edges and corners present on these filler particles under loading conditions. On the otherhand, for spherical type fillers that have no sharp corners, debonding seem to be the main failure mechanism. Representative volume element (RVE) approach is utilized to determine experimentally identified properties by means of Finite Element Method. In the model, the debonding among particle and matrix components is simulated through the cohesive zone model (CZM). Computational outputs are quite well compliant with experimental results. Experimental results and computational analysis indicate that along with the aspect ratio, some other morpohological characteristics of particles have a marked effect on the mechanical properties of the particle filled composites, such as presence of sharp corners and edges on the particle geometry and surface area to volume ratio of the particles.