Finite Element Analysis for Short-Beam Shear Test of Spread Carbon Fiber Reinforced Polymer Containing Microcapsules

Self-healing carbon fiber reinforced polymers (CFRPs) containing microencapsulated healing agents have been proposed to improve reliability and environmental issues. However, microcapsules (MCs) would degrade the mechanical properties of self-healing CFRPs due to their low strength and easy aggregation within the complex CFRP structure. Although we have proposed a spread carbon fiber (SCF) reinforced polymer that can suppress the aggregation of MCs, it is difficult to completely control the MC dispersion state. In this study, we used a representative volume element (RVE) modeling approach to investigate the effects of MC dispersion state, volume fraction and diameter on the elastic properties and internal stresses of MC/SCF/EP laminates. A finite element analysis of RVE models with different microstructures was performed, and the elastic properties and stress distributions of the MC/SCF/EP laminates were predicted. To validate the RVE models, the finite element analysis of short-beam shear test for the MC/SCF/EP laminates was performed using the predicted elastic properties from the RVE models and compared with the experimental results. The results show that the elastic properties of the MC/SCF/EP laminates depend on the MC dispersion state and volume fraction. It was also found that the well dispersed MCs in the MC/SCF/EP laminates resulted in the reduction of stress concentration and supported the higher shear stress. In addition, the initial slopes of the analytical and experimental load-displacement curves in the short-beam shear test showed reasonably good agreement. Therefore, the RVE modeling approach in this study is effective for predicting the properties of the MC/SCF/EP laminates and can contribute to microstructural design of the laminates.