0000000000868934
AUTHOR
J. Renard
A theoretical and experimental study to point out the notion of loading mode in damage mechanicsApplication to the identification and validation of a fatigue damage modeling for laminates composites
A model of fatigue-induced intralaminar cracking in strongly anisotropic laminates is presented. The features of the microscopic phenomenon are explicitly taken into account at the macroscopic level by the use of two variables, which define a new concept in Damage Mechanics that results not only in a coherent model of crack density evolution, but also in a coherent treatment of damage deactivation. Damage evolution indeed is strongly dependent on the local loading mode in each ply where cracking occurs. Experiments on complex lay-ups provided sufficient data for complete calibration of the model. These tests also allowed to validate the theoretical choice of the damage variable. Finally, nu…
Modelling unilateral damage effect in strongly anisotropic materials by the introduction of the loading mode in damage mechanics
Abstract Damage weakens the mechanical characteristics of materials. But this weakening can disappear if the cracks close again: this is called the unilateral effect of damage. We propose a model of this phenomenon using damage mechanics in the case of a diffuse network of identical microcracks. The microcracks state is defined with two internal state variables. These two variables are control parameters of the geometry of the microcracks. They also define the loading mode in damage mechanics as in fracture mechanics. In order to limit the anisotropy induced by the microcracks, hence by the loading, we suppose that the geometry of damage spreads into preferential directions. Therefore, this…