A ballistic material model for cross-plied unidirectional ultra-high molecular-weight polyethylene fiber-reinforced armor-grade composites

The known fiber and polymeric-matrix material properties, unit-cell microstructural characteristics and unit-cell level finite-element analyses are used to construct a new ballistic material model for 0°/90° cross-plied oriented polyethylene fiber-based armor-grade composite laminates. The model is constructed in such a way that it can be readily integrated into commercial finite-element programs like ANSYS/Autodyn [ANSYS/Autodyn version 11.0, User Documentation, Century Dynamics Inc., a subsidiary of ANSYS Inc., 2007] and ABAQUS/Explicit [ABAQUS version 6.7, User Documentation, Dessault Systems, 2007] as a user material subroutine. To validate the model, a series of transient non-linear dynamics simulations of the transverse impact of armor-grade composite laminates with two types of bullets/projectiles is carried out. The results obtained are next compared with their experimental counterparts. This comparison revealed that a relatively good agreement is obtained between the experimental and the computational analysis relative to: (a) the success of the armor panels of different areal densities in defeating the bullets at different initial bullet velocities; (b) post-mortem spatial distribution of damage within the panels; (c) the temporal evolution of a bulge at the back-face of the armor; and (d) the existence of three distinct armor-penetration stages (i.e. an initial filament shearing/cutting dominated stage, an intermediate stage characterized by pronounced filament/matrix de-bonding/decohesion and the final stage associated with the extensive bulging of the armor panel).