Parametric Damage Modelling of Composites Due to Moisture Absorption

This article presents a theoretical parametric model for the assessment of strength degradation of composite laminates subjected to different degrees of moisture concentration. The model is based on the real observation that the failure mechanism of composites after moisture absorption always initiates as debonding at the interface be tween the reinforcement and the matrix. In the development of the model, the composite is treated as a three-phase material: (1) the reinforcing fibers, (2) a thin bonding layer be tween matrix and fibers, and (3) the matrix. The material properties are assumed to be af fected by the moisture content according to a linear empirical relation. Finally, the overall performance of the composite is determined by the combined effect of all the empirical pa rameters related to the three phases.