Effect of Moisture Content and Salinity on Impact Strengths of Glass-Reinforced Plastics and Aluminum Honeycomb Sandwich Composites: An Experimental Investigation

Polymer composites, such as fiber-reinforced plastics (FRPs), are widely used in shipbuilding, aerospace, and automobile industries due to their lightweight and high strengths. In real-world conditions, ship hulls are exposed to harsh environmental factors, including variations in moisture and salinity. FRPs tend to absorb water and moisture, leading to an increase in weight and a reduction in strengths over time, which is undesirable for ship and aircraft structures. This study investigates the reduction in energy absorption and specific energy absorption of glass FRPs (GFRP) and aluminum honeycomb sandwich composites (AHSC) due to exposure to moisture and salinity. Experimental analysis was conducted by immersing the materials in saline and non-saline water. A comparative assessment of the percentage reduction in specific energy absorption (SEA) of GFRP and AHSC is presented. Additionally, the influence of honeycomb parameters such as cell size (CS), foil thickness (FT), and core height (CH) on SEA has been analyzed. Results indicate a 27% reduction in SEA for GFRP and a 7% reduction for AHSC due to water absorption. Furthermore, SEA in AHSC can be improved by changing honeycomb parameters, with foil thickness having the most significant impact on SEA enhancement.