Numerical modeling on compressive behaviors of 3-D braided composites under high temperatures at microstructure level

This paper reports a numerical modeling on the compressive behaviors of 3-D braided carbon/epoxy composites with different braided angles under high temperatures at microstructure level. The coupling effect of temperature and braided angle on the compressive failure mechanisms and damage morphologies have been calculated with finite element method (FEM) and compared with experimental results. In the FEM model, the imperfect interfacial bonding and the fibers with waviness were introduced into the FEM model. The ductile/brittle transition temperature was investigated and the ductile failure criterion was employed in the FEM model at high temperatures. It was found that braided angle affects the compressive failure. The compressive failure changes from ductile to brittle when the braided angle changes from larger to smaller one. The high temperature has almost no influence on the damage mode but it leads to the failure modes more ductile. The thermal stress improves the longitudinal compressive properties. The higher temperature and larger braided angle lead to the ductile behaviors of the 3D braided under longitudinal compression.