Negative Poisson's Ratio Cellular Structures for Impact Energy Absorption

Solution Overview

Problem

Existing materials lack effective solutions for absorbing and attenuating various forms of energy, such as sound waves, impacts, light, magnetic fields, and radiation, while maintaining durability and structural integrity.

Innovation Solution

Development of materials with negative Poisson's ratio (NPR) structures, including corrugated paper and composite window and MRI machine components, which utilize NPR cells and foams to absorb and redirect energy through specific cellular structures and layering configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If traditional positive Poisson's ratio (PPR) materials are used for energy absorption, then structural integrity is maintained, but energy absorption capability and impact resistance are insufficient

Engineering Contradiction:

Improveenergy absorptionVSAvoidimpact resistance

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent changes the Poisson's ratio parameter from positive to negative by modifying the cellular structure geometry. The NPR cells have inwardly angled side walls that cause lateral contraction during compression, fundamentally altering the material's mechanical response to improve energy absorption while maintaining structural integrity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates composite structures by combining NPR cells with traditional PPR cells in alternating patterns within the same foam structure. This composite approach allows the NPR regions to provide superior energy absorption while PPR regions maintain structural stability, achieving both improved energy absorption and impact resistance simultaneously

Inventive Principle:

Principle #40Composite materials

2Reliability

If denser materials are used to improve impact resistance, then durability increases, but weight increases

Engineering Contradiction:

ImprovedurabilityVSAvoidweight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent changes the Poisson's ratio parameter from positive to negative by modifying the cellular structure geometry. The NPR cells have inwardly angled side walls that cause lateral contraction during compression, fundamentally altering the material's mechanical response to improve energy absorption while maintaining structural integrity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates composite structures by combining NPR cells with traditional PPR cells in alternating patterns within the same foam structure. This composite approach allows the NPR regions to provide superior energy absorption while PPR regions maintain structural stability, achieving both improved energy absorption and impact resistance simultaneously

Inventive Principle:

Principle #40Composite materials

3Loss of energy

If conventional foam structures are used, then manufacturing is simple, but energy absorption and attenuation capabilities are limited

Engineering Contradiction:

Improveenergy attenuationVSAvoidmanufacturing complexity

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

The patent changes the Poisson's ratio parameter from positive to negative by modifying the cellular structure geometry. The NPR cells have inwardly angled side walls that cause lateral contraction during compression, fundamentally altering the material's mechanical response to improve energy absorption while maintaining structural integrity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates composite structures by combining NPR cells with traditional PPR cells in alternating patterns within the same foam structure. This composite approach allows the NPR regions to provide superior energy absorption while PPR regions maintain structural stability, achieving both improved energy absorption and impact resistance simultaneously

Inventive Principle:

Principle #40Composite materials

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

These NPR materials demonstrate enhanced energy absorption, impact resistance, and structural integrity, while being lighter in weight and more durable than traditional positive Poisson's ratio (PPR) materials, effectively attenuating or redirecting energy across different forms.

Implementation Method 1

NPR materials are durable and capable of attenuating or absorbing energy, such as sound waves, energy from impact, electricity, light, magnetic fields, or energy released from chemical reactions

Methodology Applied

Scientific EffectNegative Poisson's ratio effect: Auxetic Materials

Implementation Method 2

application of a compressive force between the top and bottom walls of the NPR cell causes a lateral dimension of the NPR cell between opposite side walls to decrease

Methodology Applied

Scientific EffectCompression: Compression

Data Source

PatentUS20240353511A1Negative poisson's ratio materials for energy absorption

Publication Date: 2024.10.24 PARK JOON BU

AI summary

Corrugated paper includes first and second sheets of paper; and a layer of structured paper disposed between the first and second sheets of paper. The layer of structured paper includes cells, in which at least some of the cells are negative Poisson's ratio (NPR) cells. Each NPR cell includes top and bottom walls, and side walls angled inwards toward a central portion of the NPR cell, such that application of a compressive force between the top and bottom walls of the NPR cell causes a lateral dimension of the NPR cell between opposite side walls to decrease. The NPR cells exhibit a Poisson's ratio of between 0 and −1.