International audienceFiber breakage and fiber pull-out induce loss of stiffness, anelastic strains, hysteresis loops, and crack closure. Ultimate strength properties of fiber-reinforced composites are derived and compared with results related to localization. These features are analyzed in the framework of continuum mechanics through the introduction of internal variables. Three models which are progressively more faithful to the micromechanical analysis are studied. They provide guidance on the choice of the relevant internal variables to model the mechanical behavior of unidirectional fiber-reinforced composites
