Variable Adhesion Fiber-Matrix Composite Armor

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Solution Overview

Problem

Existing armor panels face challenges in achieving high optical transparency while providing improved ballistic performance with minimal weight, as they often suffer from increased mass and bulk due to dense materials, and experience significant loss in optical performance post-impact due to crack propagation.

Innovation Solution

A composite article with varying fiber-matrix adhesion levels throughout its layers, where the adhesion level increases or decreases progressively from one face to the other, allowing controlled fiber movement and energy absorption during impacts, thereby maintaining optical clarity and enhancing ballistic resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If glass and acrylic sheets are laminated to improve ballistic resistance, then protection against projectiles is enhanced, but the overall mass and bulk of the armor panel increases significantly

Engineering Contradiction:
Improveballistic resistanceVSAvoidmass of armor panel
Core Design Contradiction:
StrengthVSWeight of stationary object

Solution Approach 1:

The patent employs a composite structure consisting of multiple layers including glass sheets, acrylic sheets, and polycarbonate layers laminated together. This composite material approach allows the armor panel to achieve enhanced ballistic resistance through the synergistic combination of different materials, each contributing specific properties such as hardness, toughness, and energy absorption, while optimizing the overall weight compared to using a single dense material throughout

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The armor panel is divided into multiple discrete layers with distinct functions: glass layers for initial projectile engagement and hardness, acrylic layers for optical clarity and intermediate protection, and polycarbonate layers for energy absorption and ductility. This segmentation allows each layer to be optimized for its specific role, improving ballistic performance without requiring excessive thickness of any single material

Inventive Principle:
Principle #1Segmentation

2Illumination intensity

If transparent materials are used to maintain optical performance, then visibility is preserved, but crack propagation from impact sites causes significant loss of optical performance in the remainder of the panel

Engineering Contradiction:
Improveoptical transparencyVSAvoidoptical performance after impact
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent incorporates ductile polycarbonate layers between the more brittle glass and acrylic layers to act as a cushioning element that absorbs impact energy and prevents crack propagation. This prior cushioning approach ensures that when an impact occurs, the ductile layer yields and absorbs energy before cracks can propagate through the transparent acrylic and glass layers, thereby maintaining optical performance across the entire panel

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent changes the mechanical parameters of the composite structure by introducing materials with different ductility characteristics. The polycarbonate layers provide high ductility and toughness, while the glass and acrylic provide hardness and optical clarity. This parameter differentiation allows the structure to absorb impact energy through controlled deformation in the polycarbonate layers while the transparent layers maintain their optical integrity

Inventive Principle:
Principle #35Parameter changes

3Strength

If dense materials like glass are used to provide sufficient ballistic protection, then projectile resistance is improved, but the thickness and bulk of the armor panel increases

Engineering Contradiction:
Improveballistic protectionVSAvoidbulk of armor panel
Core Design Contradiction:
StrengthVSVolume of moving object

Solution Approach 1:

The patent uses a composite material system where glass sheets provide hardness and initial projectile engagement, while thinner layers of acrylic and polycarbonate provide toughness and energy absorption. This composite approach achieves sufficient ballistic protection with reduced overall thickness compared to using thick layers of dense glass alone, as the combination of materials provides synergistic protection mechanisms

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The armor panel applies different material properties at different locations and layers: hard, brittle glass layers are positioned to engage the projectile first and provide localized hardness, while ductile polycarbonate layers are positioned deeper to absorb energy through deformation. This local quality differentiation allows each layer to be optimized for its specific function, reducing the need for excessive thickness throughout the entire panel

Inventive Principle:
Principle #3Local quality

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 composite article effectively decelerates projectiles by distributing tensile strain over a longer fiber length, increasing energy absorption and maintaining optical performance by controlling the area impacted and delamination during ballistic events.

Implementation Method 1

The composite article effectively decelerates projectiles by distributing tensile strain over a longer fiber length, increasing energy absorption

Methodology Applied
Scientific EffectEnergy absorption:

Implementation Method 2

maintaining optical performance by controlling the area impacted and delamination during ballistic events

Methodology Applied
Scientific EffectDelamination:

Data Source

PatentEP3351889B1Controlled fiber-matrix adhesion for polymer fiber composites
Publication Date: 2021.09.29 THE BOEING CO
  • EP3351889B1 patent drawingFigure 1~2
  • EP3351889B1 patent drawingFigure 3
  • EP3351889B1 patent drawingFigure 4A~4B

AI summary

A composite article includes a plurality of fibers at least partially embedded within a matrix. The fibers may be adhered to the matrix at a level of adhesion. The adhesion level between the fibers and the matrix is varied spatially within the composite article. The adhesion level varies between the layers of the composite article