Helmet Friction-Layer Design for Oblique Impact Energy Absorption

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Solution Overview

Problem

Existing helmets struggle to effectively absorb rotational energy from oblique impacts due to high friction between layers, which is costly and difficult to shape into required designs.

Innovation Solution

Incorporating a friction-decreasing intermediate layer made of fibers, such as natural or polymer-based fibers, treated with low-friction materials like silicon- or fluoro-polymers, which can be easily formed and adapted to fit various layer designs, and bonded together using methods like web forming and thermo-bonding, with optional support layers and attachment mechanisms to stabilize and secure the layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If an intermediate layer is used to allow displacement between helmet layers to absorb rotational energy, then energy absorption capability is improved, but friction between layers becomes too high to enable effective sliding

Engineering Contradiction:
Improverotational energy absorptionVSAvoidfriction force between layers
Core Design Contradiction:
Loss of energyVSForce

Solution Approach 1:

A layer of fibers is introduced as an intermediary material between the inner and outer helmet layers. This fiber layer acts as a mediator that reduces friction between the sliding layers, enabling relative displacement during oblique impacts while maintaining connection between the layers. The fibers allow the outer layer to slide over the inner layer, facilitating rotational energy absorption through the sliding mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of energy

If thin folio layers with hyper elastic material are used as intermediate layer, then rotational energy absorption is improved, but manufacturing cost and difficulty increase

Engineering Contradiction:
Improverotational energy absorptionVSAvoidmanufacturing cost and difficulty
Core Design Contradiction:
Loss of energyVSEase of manufacture

Solution Approach 1:

The invention changes the material parameters by using common fiber materials (such as textile fibers, paper fibers, or other fibrous materials) instead of expensive thin folio layers with hyper elastic material. The fibers can be obtained in rolls and are easily available, dramatically reducing material costs while maintaining the functional capability of allowing layer displacement for energy absorption.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The fiber layer uses inexpensive, readily available fibrous materials that can be easily replaced or manufactured. These fibers are commonly available in rolls and can be sourced from standard industrial suppliers, making the helmet much more cost-effective to manufacture compared to using specialized thin folio layers with hyper elastic material.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Stability of the object's composition

If complex thin folio layers are used as intermediate layer, then sliding capability is improved, but ease of shaping and handling deteriorates

Engineering Contradiction:
Improvesliding layer stabilityVSAvoidease of shaping and handling
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The invention changes the physical form from complex thin folio layers to simple fiber layers that can be supplied in rolls. These fiber layers are flexible, easy to cut, and simple to shape to fit various helmet designs. The fibrous structure naturally conforms to curved surfaces and can be easily manipulated during manufacturing without requiring specialized handling procedures.

Inventive Principle:
Principle #35Parameter changes

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 significantly reduces friction between helmet layers, allowing for efficient absorption of rotational energy from oblique impacts while being cost-effective and easily manufacturable, enhancing the helmet's ability to manage tangential forces and protect body parts from excessive forces.

Implementation Method 1

an intermediate layer of friction decreasing material adapted to be placed between two layers to create a sliding movement between the layers when an oblique force component is applied

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the fibers are treated with a low friction material, wherein the low friction material is a silicon- or fluoro-polymer

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 3

absorb rotational energy created by oblique impacts to the helmet

Methodology Applied
Scientific EffectEnergy absorption: Damping

Implementation Method 4

heat bonding or spund lacing

Methodology Applied
Scientific EffectHeat bonding: Welding

Implementation Method 5

ultrasonic bonding

Methodology Applied
Scientific EffectUltrasonic bonding: Ultrasonic Vibration

Data Source

PatentEP2523572B1Helmet with an intermediate layer of friction decreasing material
Publication Date: 2019.03.20 MIPS
  • EP2523572B1 patent drawingFigure 1~1b
  • EP2523572B1 patent drawingFigure 2
  • EP2523572B1 patent drawingFigure 3

AI summary

The invention according to the present invention relates to an intermediate layer (1) of friction decreasing material placed between two layers (2, 3). The intermediate layer (1) is adapted to create a sliding movement between the layers (2, 3) when a force (K) is applied and a tangential force component (KT) shears the layers. The friction decreasing material comprises fibers (F).