A meso-scale unit-cell based material model for the single-ply flexible-fabric armor

A meso-scale unit-cell based material model for a prototypical plain-woven single-ply flexible armor is developed and implemented in a material user subroutine for use in commercial explicit finite element programs. The main intent of the model is to attain computational efficiency when calculating the mechanical response of the multi-ply fabric-based flexible armor material during its impact with various projectiles without significantly sacrificing the key physical aspects of the fabric microstructure, architecture and behavior. To validate the new model, a comparative finite element method (FEM) analysis is carried out in which: (a) the plain-woven single-ply fabric is modeled using conventional shell elements and weaving is done in an explicit manner by snaking the yarns through the fabric and (b) the fabric is treated as a planar continuum surface composed of conventional shell elements to which the new meso-scale unit-cell based material model is assigned. The results obtained show that the material model provides a reasonably good description for the fabric deformation and fracture behavior under different combinations of fixed and free boundary conditions.