Simulation of Composite Tubes Axial Impact with a Damage Mechanics Based Composite Material Model

Composite tube axial impact is a benchmark problem measuring the predictive capability of composite crash simulation. A previous work revealed that MAT58 in LS-DYNA®, a continuum damage mechanics (CDM) composite material law based on Matzenmiller-Lubliner-Taylor (MLT) model, is inadequate in representing the unloading response of composite tubes that form continuous fronds in axial impact testing. To address the issue, two approaches have been attempted. The first one is to modify the compressive unloading response. The second one is to incorporate plasticity in a CDM framework. Both approaches were tested in an MLT theory based user material model. The modified MLT models improved the stability of the tube crush simulations and the simulation results.