Temperature dependence of polymer-composites used as coatings on megayacht structures

Abstract

Failures associated with thick polymer-composite coatings used on large megayacht vessels is not examined properly and missing studies lead to legal cases with not much technical background to support them. There is a lack of understanding of the thermal effect on the mechanical properties of new thick polymer-composite coatings the megayacht structures are exposed to. This work’s objective is to present the effect of elevated and low temperatures on the quasi-static response of epoxy-based polymer-composites. The results show significant thermal dependence and differing mechanical response at low and high temperatures. The effect of thermal variation that the vessels are exposed to during operation are believed to add to the ageing of the coating, nevertheless the association to failure of the materials has not been fully established in previous studies. It has been shown that probability of failure is increased at low temperatures, where brittle cracking is more likely to occur. Failure strains of materials B and C decreased by a substantial amount of about 29% and 28% respectively at low temperatures, which is likely to be the most influencing factor to the coating failure. Some materials are affected in a greater or lesser effect by elevated temperatures but the low temperatures have shown to compromise their mechanical properties, likely, hence, to subsequently affect their fatigue performance and lifetime. A common observation for all materials was the increase in tensile strength at low temperatures. Material B presented the greater increase in strength of about 80% at low temperatures. With respect to failure strain values at high temperatures, material C presented the most significant increase at 50°C, with an increase of a factor of 7 compared to the ambient temperature result. The conclusions of the study are that reduction in failure strains and increase in stiffness are possible at low temperatures, which are likely to cause early failure or compromise the overall mechanical response of the materials.