Investigation of the hygrothermal aging behavior of GFRP laminates used for a marine unmanned aerial vehicle structure

In this study, the hygrothermal aging behavior of E-glass fiber/epoxy composites was investigated. The moisture absorption data and diffusivity of the composite laminates were determined by conducting five sets of aging tests at different temperatures and humidities. Based on the Shen and Springer model and the Arrhenius model, a relationship model between environmental parameters and moisture absorption behavior was proposed, which was verified by experimental data and Fick’s law. The Rajaram empirical model was used to predict the aging strength of composite laminates as a function of moisture content. Under the condition of ultimate moisture absorption, the tensile, compression, and bending strengths of the laminate decreased by 24.126%, 11.148%, and 24.942%, respectively. Scanning electron microscopy observations showed that swelling cracks and fiber/matrix interface debonding caused by moisture absorption of the resin matrix are the key factors affecting the macroscopic properties of the composites.