Finite Element Modelling of Failure of a Multi-Material Target due to High Velocity Space Debris Impacts

Lagrangian finite element methods have been used extensively in the past to study the non-linear transient behaviour of materials, ranging from crash tests of cars to simulating bird strikes on planes. However, as this type of space discretisation does not allow for motion of the material through the mesh when modelling extremely large deformations, the mesh becomes highly distorted. This paper describes some limitations and applicability of this type of analysis for high velocity impacts. A method for dealing with this problem by the erosion of elements is proposed, where the main driver is the definition of element failure strains. Results were compared with empirical perforation results and were found to be in good agreement. The results were then used to simulate high velocity impacts upon a multi-layered aluminium target in order to predict a ballistic limit curve. LS-DYNA3D was used as the FE solver for all simulations. Meshes were generated using Truegrid.