Progressive damage and nonlinear analysis of 3D four-directional braided composites under unidirectional tension

A representative volume cell (RVC) is chosen to analyze the progressive damage behavior of 3D four-directional braided composites with large braid angle subjected to uniaxial tension. An anisotropic damage model is established by Murakami-Ohno damage theory. A new damage evolvement model is proposed, which is controlled by material fracture energy of braided composites constituents and equivalence displacements. According to the different damage modes (yarn transverse tension, compression and shear; yarn longitudinal tension and compression; matrix cracking), the different damage states and progressive damage of the braided composite are obtained. The numerical results show that the main failure modes of the braided composites are transverse tension, shear breakage of yarns and matrix cracking, which are in good agreement with the relevant experimental results in some literatures.