An experimental investigation of the impact of seawater on the compressive performance of solid and open hole glass/epoxy laminates

The compressive strength of composite materials is critical for designers. This study investigates how seawater immersion influences the mechanical properties and compressive behaviour of solid and open-hole glass/epoxy laminates used in aircraft structures. The specimens were divided into three groups: first not immersed, second immersed in seawater for 30 days, and last sun-dried 12 hours after immersion. Immersion in seawater lowered the compressive strength of solid and open-hole specimens by 40 % and 33 %, respectively. The sun-drying process after seawater immersion increased the compressive strength of solid and open-hole specimens by 5 % and 17 %. After drying, the residual strength of solid and open-hole GFRP was 65 % and 84 %, respectively. In solid GFRP composites, the seawater immersion and drying process is irreversible; besides, in open-hole composites it can be reversible. The compressive examination was numerically duplicated using a finite element method (FEM) model of the composite material.