•To decompose 3-D woven composite into micro repeat unit cells (RUCs) and meso-RUCs.•Using finite element method to calculate 3-point bending based on multi-scale RUCs.•Bending failures compared ...between numerical and theoretical are in good agreement.
This paper reports the deformation and damage mechanisms of 3D orthogonal woven composite (3DOWC) under three-point bending based on finite element analysis (FEA) at micro/meso/macro-scale level. One type of micro-scale repeating unit cell model (micro-RUC) has been established with the same fiber volume fraction of the 3DOWC. Two types of meso-scale repeating unit cell models, surface meso-RUC and inner meso-RUC, were established from fiber bundles structures. Combined with the smeared crack failure modes, the mechanical properties of fiber bundles which including the longitudinal and transverse ultimate strengths have been obtained based on properties of the fibers and the resins. Then the ultimate strengths of the surface layer and inner layer of the 3DOWC have been calculated based on the damaged surface meso-RUC and the inner meso-RUC with developed smeared cracks. Finally the 3DOWC beam was modeled with two types of elements, i.e., the surface layer elements and the inner layer elements, at the macro-scale level. The global and local responses of the beam under three-point bending, and the damage initiation and propagation, have been predicted at the full scale beam level. The numerical results were compared with the experimental results and good agreement was found.
