Influence of seawater absorption on vibrational and tensile characteristics of quasi-isotropic glass/epoxy composites

Glass fibre reinforced composites are common structural materials in civil engineering and marine applications. Exposure to moisture is the key challenge for using fibre-reinforced composites in marine structures. This study focuses on preparation of quasi-isotropic E-glass/epoxy laminates with stacking sequence [0°/90°/+45°/-45°] _s fabricated using vacuum bagging technique. Ageing studies in artificial seawater was conducted in sub-zero and ambient temperatures for a duration of 3600 h. Moisture absorption behaviour, variation of damping, stiffness properties, and microstructural failure analysis studies were carried out as per ASTM standards. Results indicate that the rate of moisture absorption depends on ageing temperature. In the current study, it is observed that composites aged in ambient temperature absorbed higher amount of moisture than sub-zero temperature aged specimen. Moisture absorption reduced stiffness and natural frequency of quasi-isotropic laminates.