Numerical modelling of composite structures under impact loads

This paper describes recent progress on the materials meddling and numerica l simulation of the impact response of fibre reinforced composite structure s. A continuum damage mechanics (CDM) model for fabric reinforced composite s is developed as a framework within which both in-ply and delamination fai lure may be modelled during impact loads. Damage evolution equations are de rived and appropriate materials parameters determined from experiment. The CDM model for in-plane failure has been implemented in a commercial explici t FE code, and new techniques are used to model the laminate as a stack of shell elements tied via contact interface conditions. This approach allows the interlaminar layers and strength reduction due to delamination to be co rrectly modelled. The code is applied to predict the response of a composit e shell impacted at low velocity by a steel impactor, and comparison betwee n predicted structural response and failure modes with observed test result s is given.