International audienceThis paper describes recent progress in materials modelling and numerical simulation of the impact response of fibre reinforced composite structures. A continuum damage-mechanics (CDM) model for fabric-reinforced composites is developed as a framework within which both in-ply and delamination failure may be modelled during impact loading. Damage-development equations are derived and appropriate materials parameters determined from experiments. The CDM model for in-plane failure has been implemented in a commercial explicit finite element (FE) code, and new techniques are used to model the laminate as a stack of shell elements tied by contact interface conditions. This approach allows the interlaminar layers to be modelled and strength reduction due to delamination to be represented; it also provides a computationally efficient method for the analysis of large-scale structural parts. The code is applied to predict the response of carbon-fabric-reinforced epoxy plates impacted at different velocities by a steel impactor. A comparison of structural response and failure modes from numerical simulations and impact tests is given which shows a good agreement for the prediction of delamination damage at low impact energies and fracture and penetration at higher impact energies

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This paper reports on recent experimental work to investigate the response of bolted carbon fibre composite joints and structures when subjected to constant dynamic loading rates between 0.1 m/s and 10 m/s. Single fastener joints were tested in both the bearing (shear) and pull-through (normal) loading directions. It was found that the joints exhibited only minor loading rate dependence when loaded in the pull-through direction but there was a significant change in failure mode when the joints were loaded in bearing at or above 1 m/s. Below 1 m/s loading rate the failure mode consisted of initial bolt bearing followed by bolt failure. At a loading rate of 1 m/s and above the bolt failed in a 'tearing' mode that absorbed significantly more energy than the low rate tests. A simple composite structure was created to investigate the effect of loading rate on a more complex joint arrangement. The structure was loaded in two different modes and at constant dynamic loading rates between 0.1 m/s and 10 m/s. For the structure investigated and the loading modes considered, only minor loading rate effects were observed, even when the dominant contribution to joint loads came from bearing. It was observed that the load realignment present in the structural tests allowed the joints to fail in a mode that was not bearing dominant, and hence the loading rate sensitivity was not expressed.

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