Fluid-Filled Shock Absorber Cells for Protective Gear
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Solution Overview
Problem
Conventional impact-attenuating foams in protective gear are ineffective for a wide range of impact energies, leading to either inadequate force absorption or excessive bulk and weight, and degrade rapidly with repeated impacts.
Innovation Solution
Hollow, fluid-filled compressible cells with resistive venting mechanisms that utilize both enclosure resistance and fluid-venting to manage impact forces, featuring adjustable enclosure shapes and venting structures to tailor impact 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 weight increase
Solution Approach 1:
The foam layer is divided into multiple discrete compression cells, each filled with fluid. This segmentation allows each cell to be optimized for specific impact energies while the collective provides broad-spectrum protection. The cells can be arranged in patterns that provide both high-energy and low-energy attenuation capabilities without requiring excessive material.
Solution Approach 2:
The invention changes the physical state of the impact-absorbing medium from solid foam to fluid-filled cells. By using incompressible fluid (water or air) instead of compressible foam, the system achieves different attenuation mechanisms: the enclosure walls deform elastically for low-energy impacts while the fluid provides hydrostatic pressure resistance for high-energy impacts, eliminating the need to increase 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:
Multiple thin compression cells are arranged in distributed patterns throughout the helmet interior rather than using a single thick foam layer. This segmentation allows the protective function to be achieved with thinner individual elements while maintaining overall coverage, reducing total bulk while preserving impact absorption capability across different energy ranges.
Solution Approach 2:
The fluid-filled cells utilize the incompressibility of fluid to provide high-pressure resistance without requiring thick cell walls or large cell volumes. The hydrostatic pressure generated by the fluid allows thin-walled cells to withstand high-energy impacts, enabling effective protection with reduced cell thickness and overall helmet bulk.
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
Enhances energy management and durability by effectively attenuating impact forces across a broader energy range, reducing material usage, and improving the performance of protective structures.
Implementation Method 1
the cell attenuates impact forces by resisting compression at least initially through both the enclosure (or walls) and the fluid. Following an initial stage of the impact, the walls may yield to allow the remainder of the impact to be attenuated via resistive fluid-venting.
Implementation Method 2
the cell attenuates impact forces by resisting compression at least initially through both the enclosure (or walls) and the fluid
Implementation Method 3
impact-attenuating structures that deform elastically and/or plastically in response to an impact force, thereby mechanically attenuating the impact
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, fluid-filled, compressible cells. In various embodiments, the cell enclosure includes one or more orifices, or vents, through which a fluid (such as air or water) can escape from the inner chamber formed by the enclosure.