Flattened Multi-Filament Polymeric Tapes for Ballistic Composites
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Solution Overview
Problem
Traditional non-woven composites for ballistic resistance face limitations in achieving high ultimate tensile strength (UTS) while maintaining high ultimate elongation percentage (UE%), leading to reduced energy absorption and versatility, especially when molded into curved shapes.
Innovation Solution
The development of polymeric tapes composed of flattened multi-filament yarns with specific twisting and bonding methods, which are then consolidated into a planar, unitary layer using heat and pressure, achieving a high UTS and UE% ratio without significant reduction in tensile strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If traditional non-woven composites use resin coating to bind fibers together, then the fibers remain bound in co-planar relationship, but the resin replaces high strength fibers reducing ballistic resistance efficiency
Solution Approach 1:
The invention extracts and eliminates the resin coating from the composite structure, replacing it with a thermoplastic binder applied only to the surfaces of the unidirectional plies. This removes the harmful resin that was replacing high-strength fibers in the bulk of the composite, thereby restoring ballistic resistance efficiency while maintaining fiber binding stability through the surface-bounder layers.
Solution Approach 2:
The invention uses a composite approach by combining unidirectional plies of high-strength fibers with thin layers of thermoplastic binder on the surfaces. This creates a multi-layer composite structure where the bulk material consists of pure fibers for maximum strength, while the surface binder provides binding functionality, achieving both goals simultaneously.
2Strength
If traditional multi-ply non-woven fabrics use 0°/90° cross-plying construction, then ballistic penetration resistance is improved, but delamination occurs when molded into curved shapes reducing versatility
Solution Approach 1:
The invention transitions from a two-dimensional cross-ply construction (0°/90° layers) to a three-dimensional architecture by stacking multiple unidirectional plies in a sequence that maintains ballistic performance while enabling curved form fabrication. The surface-bounder layers provide inter-laminar bonding that prevents delamination during molding, allowing the composite to be formed into complex curved shapes without compromising structural integrity.
3Strength
If high ultimate tensile strength fibers are used in non-woven composites, then strength is improved, but ultimate elongation percentage decreases reducing energy absorption
Solution Approach 1:
The invention changes the architectural parameters of the composite by using unidirectional plies with optimized fiber orientations and incorporating thermoplastic binder layers. This architectural modification allows the high-strength fibers to maintain their tensile strength while the binder system enables greater overall elongation of the composite structure, increasing energy absorption capacity without sacrificing fiber strength.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The resulting polymeric tapes exhibit enhanced ballistic resistance and energy absorption capabilities, with improved versatility due to their ability to maintain structural integrity when molded into complex shapes.
Implementation Method 1
applying heat and/or pressure to said array of tapes under conditions sufficient to consolidate said array of tapes into a substantially planar, unitary layer
Implementation Method 2
applying heat and/or pressure to said array of tapes under conditions sufficient to consolidate said array of tapes into a substantially planar, unitary layer
Data Source
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AI summary
High tenacity, high elongation multi-filament polymeric tapes as well as ballistic resistant fabrics, composites and articles made therefrom. The tapes are fabricated from multi-filament fibers/yarns that are twisted together, bonded together, compressed and flattened.