Statistical evaluation of composites fatigue results using normalizing techniques

Abstract

The adjustment of the S-N curve through a general statistical model and the normalization of the fatigue life of the material permit to establish equivalencies between states of damage for different stress levels. On the other side, the analysis of the stiffness curves of composites under fatigue loading provides an important information about the state of damage accumulation and the failure mechanisms inside of the material. Joining both procedures permits to present the stiffness evolution as a function of a normalized variable, instead of as a function of the number of cycles, supplying in this way the possibility of a unified study for results belonging to various load levels and histories