A finite element simulation approach to the mechanical behaviour of 3D angle-interlock fabrics at the scale of their internal components, using an implicit scheme, is presented in this paper. Based on the determination of the static equilibrium of assemblies of fibres, this approach is used first to find the unknown initial configuration of a unit cell of angle-interlock fabric, by implementing an original method to gradually separate initially inter-penetrating yarns. This method, only based on the weaving pattern, does not require any geometrical pre-processor. Various loading cases can then be simulated to characterize the non-linear behaviour of such fabrics. Applications to the determination of the initial configuration of the unit cell of a typical example of a 5-layer angle-interlock fabric, and to the simulation of a transverse compression test and a forming test are presented.