Integrated analysis of materials for offshore wind turbine blades: mechanical and acoustical coupling

This work focuses on assessing the structural degradation of offshore wind turbine blade (OWTB) materials caused by exposure to the marine environment using acoustic and mechanical methods. Samples, consisting of a glass fibre reinforced polymer (GFRP) composite laminate with a styrene-acrylo-nitrile (SAN) foam core, are subjected to an accelerated hygrothermal ageing by immersion in seawater at 28-30% salinity, thermostated at 40°C. Non-destructive characterisation using ultrasonic waves and mechanical testing, including 3- and 4-point bending tests, are carried out. These results are in agreement with mechanical tests which show an 8% reduction in maximum stress for the same immersion time.