Multi-Layer Ballistic Sheet Mouldability
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Solution Overview
Problem
Existing ballistic resistant sheets lack improved mouldability and consistent ballistic resistance, especially in curved articles, due to inhomogeneous drape and limited effectiveness against high-velocity impacts.
Innovation Solution
A multi-monolayer construction comprising a core layer of unidirectionally oriented reinforcing fibers with an elastomeric matrix material sandwiched between face layers of unidirectionally oriented fibers and non-elastomeric matrix material, optimized for enhanced bonding and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single-layer or two-layer ballistic resistant sheet is used, then the manufacturing process is simpler, but the mouldability and ballistic resistance are insufficient
Solution Approach 1:
The ballistic resistant sheet is divided into three distinct layers: a first layer with unidirectionally oriented fibers and elastomeric matrix material, a second layer with unidirectionally oriented fibers and non-elastomeric matrix material, and a third layer identical to the first layer. This segmentation allows each layer to contribute different properties, achieving superior ballistic resistance while maintaining manufacturability through a systematic multi-layer architecture.
Solution Approach 2:
The invention employs composite materials by combining different fiber-matrix systems in a three-layer configuration. The first and third layers use elastomeric matrix material (such as polyurethane or styrene-isoprene-styrene block copolymer) with unidirectionally oriented fibers, while the second layer uses non-elastomeric matrix material, creating a composite structure that leverages the advantages of both material types for enhanced ballistic performance.
2Shape
If curved ballistic resistant articles are manufactured from conventional sheets, then the articles can be shaped, but inhomogeneous drape results in inconsistent ballistic resistance
Solution Approach 1:
The three-layer construction provides local quality optimization where the middle layer with non-elastomeric matrix material offers dimensional stability and the outer layers with elastomeric matrix material provide flexibility and energy absorption. This localized functional differentiation ensures uniform drape characteristics across the entire sheet when formed into curved shapes, eliminating the inhomogeneity problems of conventional single-layer sheets.
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 solution achieves improved mouldability and increased ballistic resistance, with a 20% enhancement in V50 performance against 7.62×39 mm mild steel core bullets, and a 6% increase at lower pressures, while maintaining structural integrity and homogeneity in molded articles.
Implementation Method 1
a core layer formed of at least one, preferably at least two, first monolayer comprised of first unidirectionally oriented reinforcing fibers and an elastomeric matrix material
Implementation Method 2
each face layer formed of at least one, preferably at least two, second monolayer comprised of second unidirectionally oriented reinforcing fibers and optionally a non-elastomeric matrix material
Implementation Method 3
achieves improved mouldability and increased ballistic resistance, with a 20% enhancement in V50 performance against 7.62×39 mm mild steel core bullets
Data Source
AI summary
Ballistic resistant sheets (12), articles (10) comprising such sheets and methods of making the same are provided. The embodiments are especially adapted to facilitate the manufacture of curved ballistic resistant articles (e.g. curved ballistic resistant armor, helmets and the like). In preferred forms, the ballistic resistant sheets are a multi-monolayer construction including a core layer (12-1) formed of at least one first monolayer having first unidirectionally oriented reinforcing fibers and an elastomeric matrix material which is sandwiched between respective face layers (12-2) each formed of at least one second monolayer having second unidirectionally oriented reinforcing fibers and a non-elastomeric matrix material.