Segmented Shock Absorber for Protective Gear Impact Attenuation
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Solution Overview
Problem
Conventional impact-attenuating foams in protective gear are ineffective for a wide range of impact energies, either failing to absorb high energies adequately or being too hard for low energies, leading to inefficient material use and rapid performance degradation with repeated impacts.
Innovation Solution
A shock absorber design featuring a side wall and corrugation that attenuate impact forces in multiple stages, with the side wall deforming first, followed by the corrugation, and finally contacting a surface to provide progressive levels of force attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the density of foam is decreased to improve impact attenuation for high energy impacts, then the foam becomes softer and can absorb more energy, but the bulk and weight of the protective structure increases significantly
Solution Approach 1:
The protective structure is divided into multiple discrete compression cells rather than using a continuous foam layer. Each cell independently attenuates impact through its side walls and fluid venting mechanism, providing distributed impact protection that reduces the total material required while maintaining high energy absorption capability.
Solution Approach 2:
The impact attenuation characteristics are customized by modifying cell design parameters such as cell geometry, wall thickness, and orifice size rather than changing overall foam density. This allows optimization for specific impact energy ranges without proportionally increasing bulk and weight.
2Strength
If the thickness of foam layer is increased to improve impact attenuation, then more impact energy can be absorbed, but the bulk and weight of the protective structure increases
Solution Approach 1:
Multiple discrete cells provide cumulative impact attenuation through their collective action. The side walls of multiple cells deform sequentially during impact, extending the ride-down distance without requiring a single thick foam layer, thereby reducing overall structure thickness while maintaining energy absorption capability.
Solution Approach 2:
The discrete cells are arranged to provide continuous impact attenuation throughout the protective structure. As impact forces propagate through the structure, multiple cells engage in sequence, ensuring continuous energy absorption over an extended duration and distance without requiring excessive thickness in any single location.
3Ease of manufacture
If conventional foam is used to attenuate impact, then the structure is simple and easy to manufacture, but the performance degrades rapidly with repeated impacts
Solution Approach 1:
The discrete compression cells create a controlled porous structure that allows predictable deformation and recovery. The cellular geometry provides consistent mechanical response under repeated loading, maintaining reliable impact attenuation performance across multiple impact events while remaining manufacturable through standard molding processes.
4Strength
If foam density is increased to prevent bottoming out for high impact energies, then the foam can handle higher impacts, but it becomes too hard to adequately attenuate low energy impacts
Solution Approach 1:
Different regions of the protective structure use discrete cells with locally optimized characteristics. Cells can be designed with specific wall thicknesses, geometries, and orifice sizes tailored to local impact risk profiles, allowing the structure to effectively attenuate a wide range of impact energies from low to high without requiring uniform high-density foam throughout.
Solution Approach 2:
The discrete cell design provides multi-functional impact attenuation that works across diverse impact scenarios. The combination of side wall deformation and fluid venting mechanisms in each cell creates a universal response that effectively handles various impact energies, replacing the need for multiple different foam densities.
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
This design effectively absorbs impact forces across a broader energy range, improving the durability and customization of impact-absorption characteristics in protective gear, reducing material waste, and enhancing safety by distributing force over a longer distance and time.
Implementation Method 1
the side wall deforms to provide a first level of attenuation
Implementation Method 2
resistive yielding of the side wall
Implementation Method 3
at least a portion of the corrugation deforms to provide a second level of attenuation
Implementation Method 4
resistive yielding of the corrugation
Data Source
AI summary
A shock absorber includes a bottom rim, a top wall comprising a raised central portion and a top rim, a side wall extending between the top and bottom rims, and a corrugation surrounding a periphery of the raised central portion that (i) connects the raised central portion to the top rim, (ii) descends to a depth below half a height of the side wall, and (iii) is separated by a distance from a surface. Impact forces imparted on the shock absorber are attenuated by a first amount in a first stage by resistive yielding of the side wall; by a second amount in a second stage by depression of the central portion and resistive yielding of the corrugation associated therewith; and by a third amount in a third stage by resistive yielding of the corrugation in response to a force applied to the top rim upon contact with the surface.