A Macromechanical Damage Model of Fibrous Laminated Composites

Abstract

A new model for the damage factor in terms of strain energy densities is derived and proposed. The damage factor values can be predicted directly from the stress–strain data using the aforementioned model. Moreover, an expression of crack density ratios in terms of total strain energy densities is inferred. Their validity has been shown by comparing their results with the limited experimental data. The proposed model compares well with the model and the experimental data of Voyiadjis performed on metal-matrix laminates. A new technique, used to predict reasonably the values of crack density ratios at any fiber orientation angle using measured data in the principal material directions, is also developed. Due to difficulties encountered in the evaluation of amount of damage in composite materials up to failure, especially, when using experimental techniques, it was shown that the proposed method for finding the damage factor and crack-density ratios is sufficient and gives reasonable predictions.