Effect of damage progression on the heat generation and final failure of a polyester–glass fiber composite under tension–tension cyclic loading

The use of glass/polyester composite materials in wind turbines is increasing due to their low cost and favorable mechanical properties. The existing knowledge about the fatigue characteristics of such composites leads to rather conservative designs which are over dimensioned and hence costly. The aim of this work is the development of an approach for the characterization of composites under cyclic loadings. An investigation is performed on the reduction of stiffness and the heat generated during the progression of damage. It is shown that even in the matrix mode failure the fatigue limit can be above the monotonic damage criterion, where the composite losses its rigidity either due to plasticity or matrix fiber separation. Thus showing that polyester resins are rather brittle in nature and brittle material fracture models can be used for modeling these composites in fatigue. However the role of fibers in initiation or arresting of the cracks is not presented in this study.