This paper deals with impact damage and permanent indentation modeling. A numerical model has been elaborated in order to simulate the different impact damage types developing during low velocity/low energy impact. The three current damage types: matrix cracking, fiber failure and delamination, are simulated. Inter-laminar damage, i.e. interface delamination, is conventionally simulated using interface elements based on fracture mechanics. Intra-laminar damage, i.e. matrix cracks, is simulated using interface elements based on failure criterion. Fiber failure is simulated using degradation in the volume elements. The originality of this model is to simulate permanent indentation after impact with a ''plastic-like'' model introduced in the matrix cracking elements. This model type is based on experimental observations showing matrix cracking debris which block crack closure. Lastly, experimental validation is performed, which demonstrates the model's satisfactory relevance in simulating impact damage. This acceptable match between experiment and modeling confirms the interest of the novel approach proposed in this paper to describe the physics behind permanent indentation.

a b s t r a c tA model enabling the detection of damages developing during a low velocity/low energy impact test on laminate composite panels has been elaborated. The ply model is composed of interface type elements to describe matrix cracks and volumic finite elements. This mesh device allows to respect the material orthotropy of the ply and accounts for the discontinuity experimentally observed. Afterwards delaminations are described with interfaces similar to the ones observed with matrix cracks and the coupling between these two damages are established. In the first step, simple stress criteria are used to drive these interface type elements in order to assess the relevance of model principle. Nevertheless, the well known problem of mesh sensitivity of these criteria prevents the use of this model for now as a predictive tool but rather as a qualitative tool. An experimental validation is carried out thanks to impact experimental tests performed by Aboissiere (2003) and a very good match has been found. However, this model could predictivelly be used and would allow to foresee an original method to detect delaminations during an experimental test. This modelling has been successfully tested experimentally and compared to a C-Scan ultrasonic investigation.