No abstract

Glass-fibre-reinforced polyester (GFRP) is a composite commonly used in the manufacture of wind turbine blades. In the present work, one such material has been subject to static and dynamic tests in order to obtain data that can be applied to the design of wind turbine blades and other machine elements. The results of the static tests established a basis for the determination of a set of tension-tension (constant amplitude and sinusoidal load) dynamic tests with the aim of establishing a mathematical model in order to predict life as a function of the load state and calculate the fatigue limit. The multiplicative model (y ¼ ax b ) for y ¼ log of life and x ¼ transformed stress (a and b are characteristic parameters of the material obtained from data) matches the data quite well. The conclusion is that the GFRP studied has no fatigue limit. The possible decrease of fatigue strength of the material with solar radiation and moisture absorption was also investigated, with a negative result.