Laminated Transparency with Failure Strips for Blast Resistance

Solution Overview

Problem

Conventional window strengthening methods to resist blast pressures, such as using thicker glass or metallic structures, compromise visible light transmittance and are easily detectable, failing to provide a controlled failure orientation that reduces damage and maintains stealth.

Innovation Solution

Incorporating a polymeric interlayer with failure strips between glass plies, allowing the window to break in a predetermined orientation while remaining attached to the frame, and using polyvinylbutyral or polypropylene strips to ensure controlled failure without compromising visible light transmission or detectability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional window strengthening methods (thicker glass, metallic structures, laminated glass, safety films) are used to resist blast pressures, then the window strength and blast resistance are improved, but the visible light transmittance is reduced and the window becomes easily detectable

Engineering Contradiction:

Improveblast resistanceVSAvoidvisible light transmittance

Core Design Contradiction:

StrengthVSIllumination intensity

Solution Approach 1:

The window is segmented into multiple glass plies (first ply and second ply) separated by a polymeric interlayer. This segmentation allows each component to contribute to blast resistance while maintaining overall transparency. The interlayer acts as a separate functional element that provides structural support without significantly blocking light.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The polymeric interlayer is positioned locally between the glass plies at specific locations where it is needed for blast resistance and controlled failure. This localized approach maintains high visible light transmittance in the overall window structure while providing strength enhancement only where required for safety functionality.

Inventive Principle:

Principle #3Local quality

2Strength

If conventional window strengthening methods (thicker glass, metallic structures, perforated metal sheets) are used to resist blast pressures, then the window strength and blast resistance are improved, but the window becomes easily detectable by viewing with the naked eye

Engineering Contradiction:

Improveblast resistanceVSAvoiddetectability

Core Design Contradiction:

StrengthVSDifficulty of detecting and measuring

Solution Approach 1:

The polymeric interlayer is positioned locally between the glass plies at specific locations where it is needed for blast resistance and controlled failure. This localized approach maintains high visible light transmittance in the overall window structure while providing strength enhancement only where required for safety functionality.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The polymeric interlayer is a thin film that bonds the glass plies together and provides controlled failure capability. This thin film approach maintains the aesthetic appearance and transparency of the window while providing the necessary safety functionality, making it difficult to detect as a safety window.

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If the window is designed to break in a predetermined orientation to reduce damage, then the safety and damage reduction are improved, but the device complexity increases due to incorporated failure strips

Engineering Contradiction:

Improvecontrolled failure orientationVSAvoidstructural complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The window is segmented into multiple glass plies (first ply and second ply) separated by a polymeric interlayer. This segmentation allows each component to contribute to blast resistance while maintaining overall transparency. The interlayer acts as a separate functional element that provides structural support without significantly blocking light.

Inventive Principle:

Principle #1Segmentation

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 enables a window to break in a controlled manner, reducing injury and maintaining stealth, while maintaining high visible light transmission and being difficult to detect as a safety window.

Implementation Method 1

A polymeric interlayer is positioned between the first and second plies

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 2

heating the glass plies and interlayer to incorporate the failure strip into the interlayer and adhere the glass plies together

Methodology Applied

Scientific EffectHeating: Heating

Data Source

PatentUS9550343B2Laminated transparency with controlled failure and method of making the same

Publication Date: 2017.01.24 PPG INDUSTRIES OHIO INC

AI summary

A laminated transparency includes a first ply having a No. 1 surface and a No. 2 surface. A second ply is spaced from the first ply and has a No. 3 surface and a No. 4 surface, with the No. 2 surface facing the No. 3 surface. A polymeric interlayer is positioned between the first and second plies. At least one failure strip is incorporated into the interlayer to provide a predetermined failure orientation for the transparency.