Negative Poisson's Ratio Foam for Ski Impact Resistance

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Solution Overview

Problem

Conventional winter sports equipment lacks efficient energy absorption and impact resistance, leading to discomfort and potential injuries during use.

Innovation Solution

The use of materials with negative Poisson's ratio (NPR) in combination with positive Poisson's ratio (PPR) materials in the construction of winter sports equipment, such as skis, ice skates, snowboards, and snowmobiles, to enhance energy absorption and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional materials are used in winter sports equipment, then the equipment structure is simple and easy to manufacture, but the energy absorption and impact resistance are insufficient

Engineering Contradiction:

Improveimpact resistanceVSAvoidmaterial composition complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent applies composite materials by combining NPR materials (with negative Poisson's ratio) and PPR materials (with positive Poisson's ratio) in a layered structure. The NPR material layer provides enhanced energy absorption and impact resistance through its unique cellular structure that expands laterally when compressed, while the PPR material layer provides structural support and stiffness. This composite approach resolves the contradiction by achieving superior impact resistance without requiring complete redesign of the entire equipment structure.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the material parameter of Poisson's ratio by incorporating NPR materials with negative Poisson's ratio values (ranging from -0.1 to -0.5) into the equipment structure. This parameter change enables the material to exhibit auxetic behavior where compression in one direction causes expansion in perpendicular directions, significantly improving energy absorption and impact resistance while maintaining manageable structural complexity through controlled integration.

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If NPR materials are used to improve energy absorption, then impact resistance and comfort are enhanced, but the manufacturing process becomes more complex

Engineering Contradiction:

Improveenergy absorption efficiencyVSAvoidmanufacturing process simplicity

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

The patent segments the equipment structure into distinct layers: an NPR material layer and a PPR material layer. This segmentation allows each layer to be optimized independently for its specific function (energy absorption vs. structural support) and simplifies the manufacturing process by enabling separate fabrication and assembly of layers, rather than requiring complex monolithic NPR material construction.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent utilizes porous NPR materials with specific cellular structures (characteristic dimensions of 0.1 μm to 3 mm) that provide high energy absorption efficiency. The porous structure enables the material to deform and absorb impact energy through cell collapse and rearrangement, achieving superior energy absorption while maintaining a relatively simple manufacturing process through foam formation techniques.

Inventive Principle:

Principle #31Porous materials

3Reliability

If NPR materials are used in the equipment, then durability and impact resistance are improved, but the device weight may increase

Engineering Contradiction:

ImprovedurabilityVSAvoidequipment weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent applies local quality by positioning the heavier NPR material layer specifically in regions requiring enhanced impact resistance and energy absorption (such as the middle layer of skis or protective areas of snowboards), while using lighter PPR materials in other regions. This localized application optimizes durability where needed while minimizing overall equipment weight increase.

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 NPR materials provide improved comfort, impact resistance, and durability by efficiently absorbing energy from impacts, reducing the weight of the equipment while maintaining desired stiffness and performance characteristics.

Implementation Method 1

the middle layer includes a negative Poisson's ratio (NPR) foam material having a Poisson's ratio of between 0 and −1

Methodology Applied

Scientific EffectNegative Poisson's ratio effect: Auxetic Materials

Implementation Method 2

The NPR foam material is composed of a cellular structure having a characteristic dimension of between 0.1 μm and 3 mm

Methodology Applied

Scientific EffectCellular structure deformation: Foam

Implementation Method 3

an NPR viscoelastic foam

Methodology Applied

Scientific EffectViscoelasticity: Viscoelasticity

Data Source

PatentUS20240423316A1Negative poisson`s ratio materials for winter sports equipment

Publication Date: 2024.12.26 PARK JOON BU

AI summary

A ski includes an elongated ski body having a bottom layer defining a bottom surface of the ski, a top layer defining a top surface of the ski, and a middle layer disposed between the bottom layer and the top layer, in which the middle layer includes a negative Poisson's ratio (NPR) foam material having a Poisson's ratio of between 0 and −1.