Fluid-Filled Compressible Cells for Multi-Stage 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, often requiring increased material usage and bulk, and degrade rapidly with repeated impacts, failing to adequately manage energy absorption across varying impact forces.
Innovation Solution
The development of hollow, fluid-filled compressible cells with resistively yielding enclosures and venting mechanisms that attenuate impact forces through multiple stages, utilizing varying wall thickness, corrugations, and orifices to tailor energy management and absorption characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If foam density is decreased to improve impact attenuation for high energy impacts, then impact absorption capability is improved, but material usage and bulk increase
Solution Approach 1:
The patent divides the continuous foam layer into discrete compression cells with individual enclosures. Each cell independently attenuates impact through its enclosure walls and fluid venting, eliminating the need for excessive material while maintaining high energy absorption capability across multiple impact levels
Solution Approach 2:
The patent changes the physical state from solid foam to fluid-filled enclosure, transforming the impact attenuation mechanism from cellular compression to enclosure yielding and fluid venting. This parameter change enables adjustable impact absorption characteristics without increasing material quantity
2Reliability
If foam layer thickness is increased to improve impact attenuation, then impact absorption capability is improved, but bulk and weight increase
Solution Approach 1:
The patent segments the protective structure into multiple discrete cells that can be strategically positioned within the available space. This segmentation allows thorough utilization of volume without requiring a single thick continuous layer, reducing overall bulk while maintaining protection capability
Solution Approach 2:
The patent nests multiple compression cells within the protective structure's available volume, allowing cells to be arranged in configurations that maximize space utilization without increasing external dimensions. Cells can be nested within helmet shells or protective gear contours
3Reliability
If conventional foam is used to attenuate impact, then impact absorption is provided, but durability degrades rapidly with repeated impacts
Solution Approach 1:
The compression cells automatically reset after each impact by allowing fluid to re-enter the enclosure through the same orifice used for venting. This self-service mechanism eliminates permanent deformation and maintains consistent protection capability across repeated impacts without external intervention
Solution Approach 2:
The patent recovers the protective function after each impact by allowing fluid to re-enter the compressed enclosure, restoring the cell to its original state. This recovery mechanism prevents cumulative degradation and maintains durability across multiple impact events
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 effectively manages a broader range of impact energies with improved durability and reduced material usage, providing enhanced impact absorption and resistance across multiple stages, thereby enhancing the protective capabilities of gear like helmets and body pads.
Implementation Method 1
The cell attenuates impact forces by resisting compression at least initially through both the enclosure (or walls) and the fluid
Implementation Method 2
the fluid (e.g., air or water) resistively vents, providing an additional impact-attenuating mechanism that operates in conjunction, simultaneously or in sequence, with resistive yielding of the enclosure
Implementation Method 3
different portions and features of the cell enclosure contribute to shock-absorption at different times throughout the impact by resistively yielding in response thereto
Implementation Method 4
impact-attenuating structures that deform elastically and/or plastically in response to an impact force
Data Source
AI summary
Shock absorbers for integration into protective structures generally take the form of hollow, compressible cells. The cell enclosure may be configured to provide for two or more compression stages. For example, in various embodiments, the cell enclosure includes one or more corrugations descending from the top wall, which, upon contact with the bottom wall, contribute to impact absorption.