Effects of Matrix Microcracking on the Response of 2D Braided Textile Composites Subjected to Compression Loads

This article is concerned with the implementation of a coupled damage-elastic-plastic constitutive model for the matrix material of a 2D triaxial braided carbon fiber composite (2DTBC) subjected to compression loads. Damage in the matrix of 2DTBC is in the form of matrix microcracking which is observed in laboratory experiments of 2DTBC coupons subjected to cyclic loading. In the model, the matrix is treated as a continuously evolving solid governed by a coupled elasticplastic damage theory which is modified from the classical elasto-plastic theory. With this description of the matrix, the response of 2DTBC to compression loading is studied through the adoption of a representative unit cell that consists of a progressively damaging matrix and elastic-plastic progressively damaging fiber tows. Results from the analysis are compared against a model without evolving damage and also against available experimental data to understand the significance of matrix damage and its influence on compression load bearing capability.