Meso-structure of 2.5D woven composites and its strength prediction model

By adopting the hypothesis of rectangle section shape for warp, hexagon section shape for weft, and broken lines for the simplified orientation of warp, a unit-cell geometric model for 2.5D woven composites was developed. A progressive strength prediction model was developed based on the new model, which adopted Hashin and Mises failure criterions to identify failure of the yarns and matrix separately, and established different stiffness degradation method for different failure mode. A parametric progressive damage analysis program was developed by finite element analysis(FEA) software, which can predict the tensile strength, as well as the progressive damage behavior of bend-joint structure of 2.5D woven composite with different woven parameters, both in warp and weft directions. Compared with tensile experimental data, the strength errors are within 10% in both directions. The predicted failure modes agree well with the test results.