9. Conclusion

The properties of high-performance composites offer many advantages in fatigue compared to metallic materials. Their endurance limit in cyclic tension is higher than that of metals, and composite materials are less sensitive to the notch effect in fatigue than metallic materials. On the other hand, cyclic compression stresses remain the critical point. Any passage in compression can lead to reductions of around 30% compared to cyclic tension. This aspect must therefore remain a point of vigilance for design offices.

The nature of damage in composite materials does not depend on the type of stress, but is strongly conditioned by the anisotropic nature of these materials. The fact that they are designed as laminated structures leads to very specific types of damage, the directions of which are guided by the reinforcements. While ply cracking remains acceptable, and...