Multiphysics-based multiscale computational modeling of hydrothermal aging–induced mechanical property degradation in glass fiber-reinforced polymer composites

A multiscale computational model was developed to analyze the hydrothermal aging effect on glass fiber-reinforced polymer composites (GFRPCs). The computational framework, incorporating multiphysics simulations, integrates microscale and macroscale analyses to capture the coupled hydro-thermo-mechanical behavior of the material. At the microscale, COMSOL Multiphysics was used to model a hexagonal representative volume element (RVE) for 55%, 60%, and 65% weight fractions of fiber, by coupling moisture diffusion, heat transport, and solid mechanics physics. The homogenized effective thermomechanical properties obtained from the RVE were utilized in a macroscale finite element model to simulate the global mechanical response in both unaged and aged states. The diffusion behavior was analyzed at both scales to understand the moisture transport characteristics within the composite models. The computational findings showed that hydrothermal aging reduced the compressive strength by 26.11%, 18.43%, and 10.16%, and the flexural strength by 23.35%, 18.73%, and 14.59% for composite models with fiber weight fractions of 55%, 60%, and 65%, respectively. The numerical predictions showed good agreement with the experimental data, with deviations of less than 10%, confirming the reliability and accuracy of the proposed modeling approach.