Techniques for Relating Stresses and Strains in Fabrics and Fiber-Reinforced Composites between Various Hierarchical Scales

摘要

Fiber-reinforced composites and fabrics in armor systems and other structuressubjected to high-rate impacts resist perforation through multiple deformation andfailure mechanisms, which individually affect the constitutive stress-strain behavior ofthese materials. The complex behavior of these materials requires either a complexmesh geometry, as is characteristic of mesoscale models, or a complex materialmodel, as is characteristic of continuum models. However, many purported continuummaterial models for composites in the literature require separate elements for differentunidirectional lamina and only consider the effects of stresses and strains on thematerial behavior at the lamina scale, i.e. the material model has little knowledgeabout the fibers or matrix constituents that make up the composite. A fullunderstanding of the average stresses and strains at the element, lamina, andconstituent scales requires methods to relate stresses or strains at one scale to those atanother scale. Techniques used to bridge these scales are briefly presented here alongwith initial results comparing results using the modeling approach to ballistic impactdata found in the literature. The simulations shown here are of dry fabric layups,which are conceptually and computationally simpler, but some initial discussion ofhow the techniques apply to full composites is also presented.