RESIDUAL MODAL ENERGY EVALUATING OF FATIGUE DAMAGED COMPOSITE STRUCTURE

This paper deals with the evaluation of the residual modal energy in glass/epoxy unidirectional fibrous composite beam at a desired state. In this damaged state, the damaged elementary stiffness matrix is proposed for the evaluation of the global potential energy. The extraction of the global stiffness matrix is done as in classical finite element analysis. The prediction of the damage using Kachanov postulate is adopted. The loss rigidity phenomenon is considered as the main reason of increasing Of the damage in the composite beam. Global structural modelling of this damage is achieved by implementing the local damaged elastic law in a global structural bending formulation. Dynamical equation under its matrix form is given and solved to extract the effective modal characteristics at the given dosage of cyclic solicitations. The efficiency of this approach for damaged structures is shown for its possible implementation in FEM codes to treat more complex structures.