Flexible Helmet Liner Cells for Linear and Rotational Impact Protection
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Solution Overview
Problem
Current sports helmets, particularly those designed for contact sports, fail to adequately protect against both linear and rotational brain acceleration during impacts, leading to potential mild traumatic brain injury (MTBI), as they rely on outdated energy absorption materials and geometries that prioritize high-speed impacts over sub-concussive ones and do not account for anisotropic impact directions.
Innovation Solution
A flexible energy absorbing system comprising cells with anisotropic geometries, varying in three directions, and different packing densities, which are integrated into helmet liners to reduce both linear and rotational acceleration, while also improving breathability and comfort, and can be applied to other protective gear for enhanced impact protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional EPS foam with increased density and stiffness is used to pass high-speed impact test standards, then high-speed impact protection is improved, but protection against sub-concussive and slow speed impacts deteriorates
Solution Approach 1:
The energy absorbing system is divided into multiple discrete cells with different geometries (spherical, cylindrical, polyhedral) rather than using a homogeneous foam material. This segmentation allows each cell type to be optimized for specific impact conditions, providing both high-speed and sub-concussive impact protection through the collective response of diverse cell structures.
Solution Approach 2:
Different regions of the helmet incorporate different cell geometries and packing densities tailored to local impact risks. High-density cells are placed in areas prone to high-speed impacts, while lower-density cells are used in regions more susceptible to sub-concussive impacts, creating spatially varying protection properties throughout the helmet structure.
2Ease of manufacture
If round or axisymmetric energy absorbing elements are used, then manufacturing simplicity is improved, but protection against rotational acceleration deteriorates
Solution Approach 1:
The patent introduces asymmetric and anisotropic cell geometries (such as polyhedral cells with non-uniform face distributions) to replace traditional symmetric round elements. These asymmetric shapes create more complex stress distribution patterns during impact that are effective at reducing rotational acceleration, while still maintaining manufacturing feasibility through injection molding or similar processes.
Solution Approach 2:
The energy absorbing system transitions from two-dimensional planar arrangements to three-dimensional configurations with cells extending in multiple directions. This dimensional enhancement allows the structure to engage more effectively with rotational impact forces by distributing stresses across three-dimensional space, improving rotational protection beyond what flat or axisymmetric elements can achieve.
3Device complexity
If homogeneous bulk foam materials are used, then material simplicity is improved, but control over density distribution and impact response deteriorates
Solution Approach 1:
Instead of using homogeneous foam, the patent employs cells with locally varied geometries and packing densities. Each cell type (spherical, cylindrical, polyhedral) and its spatial arrangement is specifically designed to address local impact characteristics, enabling precise tuning of the energy absorbing response to match different impact scenarios and anatomical regions.
Solution Approach 2:
The system utilizes variations in cell geometric parameters (shape, size, wall thickness) and packing density as design variables to optimize impact response. By changing these parameters across different cell types and locations, the system achieves versatile adaptation to various impact conditions while maintaining a relatively simple overall structure composed of repeating cell units.
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 significantly reduces peak linear and rotational accelerations by up to 23% and provides tailored protection in various impact directions, enhancing safety and comfort in helmets and other personal protective equipment.
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
the first plurality of cells and the second plurality of cells comprise an elastomeric material
Data Source
AI summary
The present disclosure relates to flexible energy absorbing systems and body armor, 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.