An energy-based fatigue approach for composites combining failure mechanisms, strength and stiffness degradation

In order to improve the fatigue analysis of large structures made of fibre-reinforced plastics a physically motivated fatigue assessment procedure is investigated. In contrast to the analysis procedure usually applied the novel model consists of a layer-wise continuum mechanics approach on macro scale and considers different failure modes. The approach subdivides into two analysis parts: discontinuous quasi-static degradation and continuous fatigue degradation. The discontinuous approach is based on a well-known failure mode theory. The continuous degradation approach makes use of an energy-based hypothesis, which combines strength and stiffness degradation. With the present approach stress redistributions and sequence effects can be investigated.