3D Auxetic Hollow-Cell Structure for Omnidirectional Impact Absorption
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Solution Overview
Problem
Conventional materials and structures lack three-dimensional auxetic behavior, which limits their ability to efficiently absorb impact energy and adapt to varying loads and shapes in applications such as aerospace and marine industries.
Innovation Solution
A three-dimensional auxetic structure comprising a plurality of adjoining hollow cells with folding lines, following a two-dimensional auxetic pattern, allowing the structure to expand in one direction while contracting in the other two, and can be manufactured through 3D printing or folding of sheet materials, integrated into sandwich panels for enhanced impact resistance and morphing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional materials with positive Poisson ratio are used, then the materials get thinner when stretched and fatter when compressed, but they cannot concentrate material around impact area or provide three-dimensional auxetic behavior
Solution Approach 1:
The patent transitions from conventional two-dimensional auxetic patterns to a three-dimensional cellular structure. The hollow cells with folding lines create a 3D configuration that exhibits auxetic behavior in all three spatial directions, enabling material concentration around impact areas from any direction and providing comprehensive impact energy absorption capability.
Solution Approach 2:
The invention employs a cellular porous structure with hollow cells containing folding lines. This porous configuration allows the material to deform in a controlled manner during impact, concentrating material around the impact area while absorbing impact energy through the folding and unfolding mechanisms of the cell walls.
2Adaptability or versatility
If two-dimensional auxetic structures are used, then they exhibit auxetic behavior in two in-plane directions, but they cannot provide three-dimensional auxetic behavior for omnidirectional impact resistance
Solution Approach 1:
The patent extends the auxetic behavior from two dimensions to three dimensions by introducing hollow cells with folding lines that allow deformation in the out-of-plane direction. This 3D configuration enables the structure to exhibit negative Poisson's ratio in all three spatial directions, providing omnidirectional impact resistance and adaptability.
3Strength
If conventional honeycomb structures are used, then they provide strength and lightness, but they lack the ability to concentrate material around impact area
Solution Approach 1:
The invention utilizes a cellular porous structure with hollow cells that can deform through folding lines. This porous configuration enables the material to concentrate around impact areas while maintaining lightness, combining the strength benefits of honeycomb structures with the impact energy absorption capabilities of auxetic materials.
Solution Approach 2:
The patent employs parameter changes in the cell geometry, specifically incorporating folding lines with defined peak and valley angles. These geometric parameters control the deformation behavior, allowing the structure to concentrate material around impact areas and absorb impact energy while maintaining overall structural strength.
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 structure provides improved impact energy absorption, progressive failure mode, and adaptability to non-uniform shapes, enabling lightweight composite parts with enhanced acoustic damping and load-carrying capabilities.
Implementation Method 1
each cell wall comprises folding lines parallel to the plane containing the auxetic pattern such that peaks and valleys are defined in the cell walls and with the cell walls foldable along the folding lines
Implementation Method 2
The sandwich panel having an auxetic behavior on the three directions of space can be used as an elementary part for lightweight composite parts with potential applications that require high impact energy absorption
Implementation Method 3
enabling lightweight composite parts with enhanced acoustic damping and load-carrying capabilities
Data Source
AI summary
A three-dimensional auxetic structure, comprising a plurality of adjoining hollow cells, each hollow cell having cell walls and a transversal cross section of the plurality hollow cells following a two-dimensional auxetic pattern, each cell wall comprising folding lines parallel to a plane containing the auxetic pattern such that peaks and valleys are defined in the cell walls and the cell walls being foldable along the folding lines.