A new analytical method for progressive failure analysis of two-dimensional triaxially braided composites

A new analytical model is developed for predicting progressive damage, equivalent stiffness and strength of a two-dimensional triaxially braided composite (2DTBC) under tensile and compressive loading. In this model, an alternative concept of equivalent lamina elements (ELEs) is first established for the four subcells parallel to the axial direction in a representative unit cell of the 2DTBC; Next, the ELEs are laminated in the thickness direction and integrated via a series-parallel model to establish a two-way stress–strain response within the unit cell, that allows failure initiation and propagation in the ELEs to be examined and ultimate failure strength to be predicted. The analytical results are validated against a finite element simulation of an infinite plate as well as experimental results. Numerical case studies are conducted to assess the sensitivity of analytical results against compressive strength of ELEs. The results demonstrate the capability and efficiency of the present model for predicting the mechanical responses of single-layer and multi-layer 2DTBC specimens under different loading conditions.