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An explicit finite element modelling of the 5-harness satin woven composite material is proposed in this paper. It is based on the semi-continuous approach which consists in separating fibre and matrix mechanical behaviours. The bundles are modelled with rod elements and a specific damageable shell element is used to stabilize this truss structure. As the woven pattern geometry plays a key role in damage initiation and propagation, a modification has been made in the failure strain of the rods located at the crimp regions where warp and weft yarns cross each other. The method has been implemented into the explicit finite element code RADIOSS and is computationally efficient to model low to medium velocity impact (1-200 m/s) at the structure scale. The modelling strategy is validated by representing a drop weight test and an oblique impact test and provides good prediction of impact force history and damage size and location.

This article concerns the Finite Element modeling of impacts on composite sandwich structures. Low velocity normal impacts and medium velocity oblique impacts on sandwich panels made with woven composite skins and a polyurethane foam core are investigated. The ply orientations and materials of the woven composite laminate skin are varied. The woven skin is modeled using a semi-continuous approach, described in the first part of this two parts article, in which the behavior of the bundles of fibers and that of the resin are disconnected. The foam core is represented with solid elements with a continuous material law. This modeling strategy provides results accurate enough to represent the damage scenario observed experimentally with an acceptable calculation time. The numerical results are used to analyze the damage mechanisms leading to the final fracture shape.