Crimp-imbalanced protective fabric

#This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/070,262 filed on Mar. 21, 2008 and entitled “Crimp Imbalanced Protective Fabric Armor” by the inventor, Paul V. Cavallaro.

#None.

#(1) Field of the Invention

#A more complete understanding of the invention and many of the attendant advantages thereto will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein like reference numerals and symbols designate identical or corresponding parts throughout the several views and wherein:

#FIG. 1 depicts a prior art example of a woven fabric layer;

#FIG. 2 depicts a geometric model of prior art uni-directional crimping in plain-woven fabrics;

#The present invention is accomplished by varying the levels of yarn crimp within a layer and/or across layers of a multi-layer fabric armor system such that functionally-graded, improved protections can be achieved against ballistic and/or stab penetration threats. FIG. 8 is a prior art depiction of a fabric containing balanced crimp contents among yarn families in a plain-woven architecture while FIG. 9 depicts the inventive use of unbalanced crimp contents among yarn families in a plain-woven architecture. FIG. 10 demonstrates the graded performances as functions of crimp gradient for a multi-layered woven fabric system. Four layers are shown in FIG. 10; however, the multi-layer fabric may have even more numerous amounts of layers in individual crimp variants or sets of layers with similar crimp variants.

#The present invention also relates to crimped fabric architectures using fiber placement techniques such as woven (plain, harness, twill, satin, basket, leno, mock leno, etc.) or braided (biaxial, triaxial, quadraxial, etc.) as shown in prior art FIGS. 11-13. In relation to FIG. 12, a braid is formed when the yarns are at a non-orthogonal angle such as 30 or 60 degrees. A triaxial braid of FIG. 13 is a braid with the addition of one extra yarn family which is generally aligned along the 0-degree axis. The construction of these architectures may appear slightly different, their load-carrying capabilities and deformation shapes are significantly different. The crimped layers can be stacked in a variety of configurations along with non-woven fabrics layers and other materials (RHA steels, ceramics, etc.) to form hybrid constructions for specific applications and protection levels.

#The variations of crimp within a fabric layer and along the through-thickness direction of the multi-layered fabric armor systems may be designed to: selectively control the levels of energy absorption and blunting performance within each layer; optimally tailor variable energy absorption and blunting performance levels (including projectile tumble) in the through-thickness direction; increase protection during fragmentation from obliquely dispersed fragments (particularly within regions of oblique susceptibility); decouple the arrival of peak stress waves between yarn families; minimize stress wave reflections at the yarn crossover points; deliver the performance benefits afforded by both crimped and uni-directional fabric armor systems combined with the maintained flexibility associated with crimped fabric systems; and integrate within vehicle, personnel, structural and inflatable systems.