Multi-layer Auxetic Structure for Thermo-mechanical Expansion Management
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Solution Overview
Problem
Conventional materials exhibit positive Poisson's Ratio behavior, which limits their ability to efficiently manage thermo-mechanical expansion and porosity in industrial applications, particularly in high-temperature environments like gas turbines, where tailored negative Poisson's Ratio (NPR) behavior is required for optimal performance.
Innovation Solution
A multi-layer auxetic structure is created by overlaying sheets with distinct opening patterns and porosities, connected via specific elements, allowing for tailored porosity and NPR behavior through computer-aided design and modeling to achieve desired properties such as reduced porosity and enhanced stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional materials with positive Poisson's Ratio are used, then manufacturing and design are straightforward, but the ability to manage thermo-mechanical expansion and porosity is limited
Solution Approach 1:
The structure is divided into multiple layers, each with distinct opening patterns and porosity characteristics. The first layer provides a first porosity while the second layer provides a second porosity, and their combination creates a multi-layer structure with tailored effective porosity and NPR behavior. This segmentation allows independent optimization of each layer's properties to achieve the desired overall performance.
Solution Approach 2:
The patent combines multiple layers with different porosity characteristics and opening patterns to create a composite structure. The first sheet and second sheet, each with distinct porous structures, are integrated to form a multi-layer NPR structure that exhibits negative Poisson's Ratio behavior while maintaining tailored porosity properties for thermal management applications.
2Adaptability or versatility
If single-layer porous structures are used, then porosity is uniform, but the ability to tailor effective porosity and NPR behavior is limited
Solution Approach 1:
The structure is divided into multiple layers, each with distinct opening patterns and porosity characteristics. The first layer provides a first porosity while the second layer provides a second porosity, and their combination creates a multi-layer structure with tailored effective porosity and NPR behavior. This segmentation allows independent optimization of each layer's properties to achieve the desired overall performance.
Solution Approach 2:
Different regions of the structure (different layers) have different porosity properties and opening patterns. The first sheet and second sheet are designed with distinct local characteristics that, when combined, provide the desired effective porosity and NPR behavior. This local quality variation enables precise control over the structure's macroscopic properties.
3Temperature
If cooling holes are provided in combustor liners, then thermal management is improved, but stress concentrations and structural integrity are compromised
Solution Approach 1:
The patent employs porous structures with engineered opening patterns and tailored porosity to provide thermal management functionality. The porous architecture allows for controlled heat transfer and cooling while maintaining structural integrity through the distributed nature of the porosity, avoiding stress concentrations associated with discrete cooling holes.
Solution Approach 2:
The multi-layer porous structure combines different porosity characteristics to achieve both thermal management and structural strength. The composite architecture distributes stress more evenly compared to conventional cooling hole configurations, maintaining structural integrity while providing effective cooling.
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 multi-layer auxetic structure effectively mimics negative Poisson's Ratio behavior, reducing transverse expansion under axial compression and enhancing thermal management and stress reduction in industrial components, such as gas turbine combustors, while allowing for tailored porosity and improved load-bearing capacities.
Implementation Method 1
materials with a negative Poisson's Ratio (NPR), also known as 'auxetic' materials, will contract in the transverse direction when compressed in the axial direction and expand in the transverse direction when stretched in the axial direction
Data Source
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AI summary
In some aspects, an auxetic structure includes a first sheet and a second sheet, the first sheet defining therein a plurality of first openings in a first pattern, the plurality of first openings providing a first porosity and the second sheet defining therein a plurality of second openings in a second pattern to provide a second porosity. The second sheet is positioned to overlay the first sheet so that the plurality of second openings at least partially occlude the plurality of first openings to define a plurality of third openings in a third pattern, the plurality of third openings defining a third porosity less than that of the first porosity or the second porosity. The second sheet is connected to the first sheet by a plurality of distinct connection elements. In other aspects, one or more additional sheets defining therein one or more opening and porosities are provided in combination with the aforementioned first and second sheet.