Damage Model For Laminates Research Articles

Intralaminar Damage Model for Laminates Subjected to Membrane and Flexural Deformations

Prediction of transverse damage initiation and evolution for not necessarily symmetric laminates under membrane and/or bending loads is the subject of this work. The laminate stiffness reduction is computed via crack opening displacement (COD) methods and the generalization to multiple cracking laminas is made via continuum damage mechanics (CDM) concepts. Using available COD solutions combined with homogenization techniques leads to an analytical constitutive model capable of predicting the initiation and evolution of crack density versus applied strain, as well as laminate modulus degradation, not only for symmetric laminates subjected to membrane deformation but also for general laminates subjected to flexural deformations as well. To adjust the model parameters, experimental data is required in the form of crack density, or modulus reduction, versus strain for two laminates of the same material system. Then, the model is capable of predicting crack density and modulus degradation for other laminate stacking sequences. The model takes into account crack closure, which is important under flexure, as well as the case of the center lamina straddling the neutral axis. The effect of thermal stresses is incorporated in the formulation.

A multi-scale progressive damage model for laminates

Predicting the strength of composite laminates subjected to complex multi-axial loading based on the properties of the constituents, fibres and matrix, remains a major technical challenge. The purpose of this paper is to present a multi-scale progressive damage model for composite laminates. At the lamina scale, stress-based failure criteria are proposed for the fibres and the matrix, with the stresses required in the failure criteria being determined by a micro-mechanics analysis. Linking the lamina scale with the laminate scale is achieved through a finite element micromechanics model and a progressive damage model. Comparison has been carried out with the experimental data generated during the world-wide failure exercise, indicating a good agreement for several materials over a wide range of loading conditions.

A delay damage mesomodel of laminates under dynamic loading: basic aspects and identification issues

This paper deals with the modeling of damage in laminates under dynamic loading. In the first part, the basic aspects of the model, which were developed in previous studies, are described. In the second part, we focus on current developments concerning the identification of the model using dynamic experiments. Since the applications are related to the design of composite crash absorbers, particular attention is given to the dissipation of energy.