Reticulated Foam Density Gradients for Energy Absorption
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Solution Overview
Problem
Existing methods for manufacturing open celled foams, such as DUOCEL, are limited by their homogeneous relative density and inability to achieve complex geometries, leading to restricted design capabilities and performance in applications like energy absorption and filtration systems, where customized relative density and porosity across a part are necessary.
Innovation Solution
The development of methods to create heterogeneous relative density open celled DUOCEL structures through densification processes using presses and dies, allowing for customized relative density ranges from 3-85% across a single part, enabling optimized system performance in applications like energy absorbers and filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If homogeneous relative density foam structures are used, then manufacturing simplicity is maintained, but design versatility and performance optimization are limited
Solution Approach 1:
The patent applies local quality by creating heterogeneous foam structures with varying relative densities within different regions of the same component. This allows specific areas to have optimized properties for their intended function, such as higher density for structural support and lower density for weight reduction, thereby achieving design versatility without requiring multiple different components.
Solution Approach 2:
The invention segments the foam structure into regions with different relative densities, allowing each segment to be optimized for specific performance requirements. This segmentation enables complex geometries and customized density distributions while maintaining the structure as a single integrated component, resolving the contradiction between versatility and complexity.
2Strength
If open celled foam structures are compressed to high relative density, then structural integrity improves, but the material fails due to lower yield stress
Solution Approach 1:
The patent resolves this contradiction by creating local quality variations in density throughout the foam structure. Regions requiring high structural integrity are densified to higher relative densities, while other regions maintain lower densities to preserve yield stress and prevent catastrophic failure. This localized density control allows the structure to achieve overall integrity without sacrificing material reliability.
3Adaptability or versatility
If 3-D printing is used to create complex geometries, then design freedom improves, but manufacturing cost and setup time increase
Solution Approach 1:
The patent replaces complex 3-D printing mechanical systems with a chemical foaming process that naturally forms complex geometries through controlled expansion of foam precursors. This substitution allows complex shapes to be manufactured using simpler, more cost-effective chemical processes rather than expensive additive manufacturing equipment, thereby improving manufacturing efficiency while maintaining geometry customization capability.
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 approach enhances the structural integrity and energy absorption capabilities of DUOCEL structures, enabling them to compete with 3-D printed materials by allowing for progressive relative density distribution and complex geometries, thereby improving system performance and versatility.
Implementation Method 1
enhances the structural integrity and energy absorption capabilities of DUOCEL structures
Implementation Method 2
open celled foam structures that are manufactured using additive processes, to include CVD and 3-D printing, often fail when compressed due to the lower yield stress (foam modulus)
Data Source
Figure 1~3
Figure 4~5A
Figure 5B~6A
AI summary
Heterogeneously dense (relative density) continuous one-piece insoluble reticulated foam material with a continuous relative density gradient and/or distinct and marked relative densities and methods of manufacture.