Meso-scale finite element analyses of three-dimensional five-directional braided composites subjected to uniaxial and biaxial loading

A meso-scale finite element-based model has been developed to evaluate the uniaxial and biaxial strength characterizations of three-dimensional five-directional braided composites. The representative volume cells are established based on the realistic geometry cross sections. A continuum damage mechanics model, which is implemented as a user-defined material subroutine in the ABAQUS commercial finite element code, is introduced to predict the mechanical responses and the failure locus under uniaxial and biaxial loadings. For the verification of numerical results, a series of tensile and compressive tests are conducted along the longitudinal and transverse directions. The results show that under uniaxial loading, the calculated max stress and the final damage morphology agree well with the experimental data. Moreover, it is found that the interaction effect between the axial stress and the shear stress is not apparent, whereas that between two axial stresses becomes significant. It is expected that such a numerical investigation will provide useful information for building a strength criterion of three-dimensional five-directional braided composites.