Micromechanics-based finite element modeling of damping in hollow spheres/fiber-reinforced polymer composites

Unidirectional fiber-reinforced polymer matrix composites (PMCs) have great potential for engineering applications. The effective properties can be further tailored by incorporating a secondary reinforcement into these materials. This study investigates the damping characteristics of PMCs reinforced by both unidirectional glass fibers and hollow glass microspheres (HGMs) using a micromechanics-based finite element method (FEM). To account for the complex nature of the filler/matrix dissipation mechanisms, a thin, lossy interphase layer is considered for both the fibers and HGMs inside the representative volume element (RVE) of the PMCs. The numerical homogenization approach is first validated against analytical, numerical, and experimental data from the literature. Subsequently, a comprehensive parametric study is conducted to examine the influence of microstructural features on the composite’s damping behavior. Specifically, the effects of thickness, stiffness, and damping properties of the interphase, as well as fiber volume fraction (FVF), HGM volume fraction (HVF), and HGM thickness on the directional loss factors are evaluated using the strain energy approach. The findings indicate that while an increase in FVF generally reduces the damping performance of the composite, a weak interfacial bond between the fillers and the matrix can enhance the damping properties of hybrid filler-reinforced PMCs.