Synergistic effects of marine environments and flexural fatigue on carbon fiber-vinyl ester composites protected by gelcoat

The current process for designing reliable and enduring naval composite crafts and structures is instrumentally dependent upon utilizing protective coatings to shield composite materials against environmental based degradation. However, as coatings can be vulnerable to corrosion and/or erosion in harsh marine environments, they may gradually lose their protective abilities, leading to damage accumulation in the protected composites. To demonstrate the criticality of this process, gel-coated carbon fiber-vinyl ester laminates are subjected to a simulated marine environment consisting of ultraviolet (UV) radiation, moisture, and cyclic mechanical loading. Next, degradation in composite laminates is probed through measuring the flexural strength. Damage in gelcoat is further characterized by digital microscopy of its surface. Correlation between degradation of the gelcoat surface and loss in the mechanical properties of coated composite laminates is also investigated.