Finite-element homogenization of short glass fiber/silicone rubber composites: Experimental validation of RVE and orientation-Averaged RVE methods

A novel silicone rubber (SR) composite reinforced with randomly dispersed short glass fibers (SGFs) was developed and experimentally characterized. Five composite groups, with fiber weight fractions ranging from 5 wt% to 25 wt%, were fabricated and tested under uniaxial tension according to ASTM standards. Experimental test showed that composite stiffness increased proportionally with fiber reinforcements content, 33% for 5% fiber wt% to 200% for 25% of fiber wt%. Two finite element-based homogenization approaches were employed: the Representative Volume Element (RVE) and the Orientation-Averaged RVE (OARVE). Both were validated against experimental stress–strain data and four established analytical homogenization models. While the OARVE method offered computational efficiency, it failed to capture micromechanical behaviors such as fiber microbuckling and protrusion. Analytical models served as upper and lower bounds for stiffness estimation. Quantitatively, OARVE overestimated stiffness by nearly 10x, whereas RVE showed 15–50% error. Both experimental and simulation results confirmed that increasing fiber content enhances stiffness in the linear elastic regime.