Interdigitated Cellular Cushioning for Controlled Energy Absorption
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Solution Overview
Problem
Conventional cushioning systems, such as those used in impact protection and comfort applications, often lack a controlled spring rate over their deformation range and can break down over time, failing to effectively absorb kinetic energy across various load ranges.
Innovation Solution
An interdigitated cellular cushioning system comprising two sheets of resilient material with arrays of void cells, where each void cell's peak contacts a binding layer, allowing for monotonically collapsing cells that absorb kinetic energy without collapsing the binding layer, providing a configurable spring rate profile and enhanced energy absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cushioning systems (foam, closed-cell air chambers, elastomeric honeycomb) are used, then cushioning function is provided, but the structures break down over time and lack controlled spring rate
Solution Approach 1:
The cushioning system is divided into multiple discrete void cells arranged in arrays within binding layers. Each void cell acts as an independent energy-absorbing unit with controlled collapse characteristics, preventing the breakdown and degradation seen in conventional foam and honeycomb structures while maintaining overall structural integrity.
Solution Approach 2:
The spring rate and energy absorption characteristics are controlled by varying parameters such as void cell geometry, wall thickness, material properties, and cell arrangement. This allows customization of the force-deflection profile to achieve desired cushioning performance while maintaining structural stability over time.
2Force
If conventional cushioning structures are used, then impact protection is provided, but they lack controlled spring rate over the deformation range
Solution Approach 1:
Different regions of the cushioning system can have void cells with different geometries, wall thicknesses, or material properties to create localized variations in spring rate. This allows customization for specific application requirements while maintaining overall system performance.
Solution Approach 2:
The void cells are designed to collapse in a controlled, progressive manner during deformation, providing a dynamic spring rate that changes with compression level. This allows the system to adapt to different impact energies and deformation ranges while maintaining predictable force-deflection characteristics.
3Loss of energy
If void cells are made to collapse monotonically to absorb kinetic energy, then energy absorption is improved, but the binding layer may collapse
Solution Approach 1:
The binding layers are designed with sufficient strength and stiffness to withstand the collapse forces of the void cells during energy absorption. The void cell geometry and material properties are selected to ensure that cell collapse occurs before binding layer failure, providing predictable energy absorption while protecting the binding layer structure.
4Duration of action of stationary object
If conventional foam structures are used, then cushioning is provided, but they break down over time
Solution Approach 1:
By dividing the cushioning system into discrete void cells with defined collapse mechanisms, the system avoids the progressive degradation and breakdown that occurs in conventional foam structures. Each void cell maintains its structural integrity until designed collapse, providing consistent performance over the service life.
Solution Approach 2:
The void cells are designed as sacrificial elements that absorb energy through controlled collapse rather than permanent deformation. This allows the binding layer structure to remain intact and reusable, while the void cells provide disposable energy absorption capacity that prevents overall system failure.
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 interdigitated system effectively absorbs kinetic energy across multiple load ranges, reducing the transmission of energy to users or surfaces, and can change the path of projectiles, enhancing protection and comfort by maintaining structural integrity and customizable energy absorption.
Implementation Method 1
the void cells are configured to monotonically collapse under a load, wherein a peak of each void cell in the first array contacts the second binding layer and a peak of each void cell in the second array contacts the first binding layer
Implementation Method 2
a first sheet of resilient material including a first binding layer and a first array of void cells protruding from the first binding layer
Data Source
AI summary
An interdigitated cellular cushioning system includes an array of void cells protruding from each of two sheet layers interdigitated between the two sheet layers. Peaks of each of the void cells are attached to the opposite sheet layer forming the interdigitated cellular cushioning system. The interdigitated cellular cushioning system may be used to absorb and distribute a source of kinetic energy incident on the interdigitated cellular cushioning system (e.g., an impact or explosion) so that the amount of force transmitted through the interdigitated cellular cushioning system is low enough that it does not cause injury to personnel or damage to personnel and/or equipment adjacent the interdigitated cellular cushioning system.