Flexible Elastomeric Cell Structure for Multi-Directional Impact Absorption
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Solution Overview
Problem
Current energy absorbing systems in helmets, particularly those used in sports, are inadequate in reducing both linear and rotational brain acceleration during impacts, leading to traumatic brain injuries, and lack flexibility and directional protection, which are critical for effective head and limb protection.
Innovation Solution
A flexible energy absorbing system comprising cells with anisotropic geometries and varying packing densities, designed to provide different levels of protection in multiple directions, enhancing comfort and breathability by using elastomeric materials with strain rate sensitivity and complex re-entrant geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If EPS density and stiffness are increased to pass high speed test standards, then linear acceleration protection is improved, but protection against sub-concussive and slow speed impacts deteriorates
Solution Approach 1:
The patent employs multiple cell geometries with different mechanical properties (re-entrant, elongated, polyhedral, spherical cells) to provide a range of stiffness values. This allows the foam to respond appropriately to different impact severities, from sub-concussive to high-speed impacts, resolving the contradiction between protecting against linear acceleration and sub-concussive impacts.
Solution Approach 2:
The patent creates a composite foam structure combining multiple cell types within a single material system. The different cell geometries work together to provide both high-speed impact protection (through stiffer re-entrant and elongated cells) and sub-concussive impact protection (through more compliant polyhedral and spherical cells), achieving dual protection capabilities.
2Ease of manufacture
If traditional round or axisymmetric elements are used in energy absorbing systems, then manufacturing simplicity is improved, but protection against rotational acceleration deteriorates
Solution Approach 1:
The patent introduces asymmetric cell geometries (elongated cells, polyhedral cells, and re-entrant cells with specific orientation patterns) that are specifically designed to resist rotational acceleration. These asymmetric structures provide torque resistance and rotational control that round elements cannot achieve, while still being manufacturable through standard foam molding processes.
Solution Approach 2:
The patent transitions from isotropic round elements to anisotropic cells with specific orientations and shapes that address the third dimension of rotational protection. The elongated and polyhedral cells provide directional stiffness and rotational resistance, adding a new dimension of protection against rotational acceleration while maintaining manufacturing feasibility.
3Device complexity
If homogeneous bulk foam materials are used in protectors, then material simplicity is improved, but directional protection performance and breathability deteriorate
Solution Approach 1:
The patent applies local quality by distributing different cell geometries in specific regions of the foam. Certain areas contain more re-entrant cells for high-speed impact protection, while other regions have polyhedral or spherical cells for sub-concussive protection and breathability. This spatial variation in cell structure provides directional protection performance while maintaining overall material simplicity.
Solution Approach 2:
The patent utilizes the porous structure of foam materials with different cell geometries to enhance breathability while providing directional protection. The interconnected cell structures allow air flow and moisture vapor transmission, improving comfort and thermal regulation, while the varying cell types provide tailored protection in different directions and impact scenarios.
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 system effectively reduces both linear and rotational brain acceleration, improves protection against sub-concussive impacts, and offers tunable performance in various directions, enhancing safety and comfort in helmets and other protective gear.
Implementation Method 1
a flexible energy absorbing system comprising a first plurality of cells comprising a first re-entrant geometry and a second plurality of cells comprising a second, different geometry, wherein the first plurality of cells and the second plurality of cells comprise an elastomeric material
Implementation Method 2
wherein the first plurality of cells and the second plurality of cells comprise an elastomeric material
Implementation Method 3
designed to provide different levels of protection in multiple directions, enhancing comfort and breathability by using elastomeric materials with strain rate sensitivity
Data Source
Figure 1a~1c
Figure 2a~2c
Figure 3a~3d
AI summary
The present disclosure relates to flexible energy absorbing systems and body armour, helmets and protective garments incorporating flexible energy absorbing systems. A flexible energy absorbing system may comprise a first plurality of cells having a first re-entrant geometry and a second plurality of cells having a second, different geometry. The first plurality of cells and the second plurality of cells may comprise an elastomeric material.