Zero-Porosity NPR Structure for High-Temperature Stress Resistance
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Solution Overview
Problem
Conventional materials used in high-temperature applications, such as gas turbine combustors, often require porosity for cooling but suffer from stress and fluid permeability issues, limiting their effectiveness.
Innovation Solution
A zero-porosity structure with a Negative Poisson's Ratio is achieved by arranging structural elements, such as spherical caps or ellipsoidal shapes, in specific tiling patterns that transform the material's behavior from Positive to Negative Poisson's Ratio, reducing stress and allowing for non-porous, high-stiffness designs suitable for high-temperature environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If porosity is introduced for cooling in high-temperature applications, then heat dissipation is improved, but stress resistance and fluid permeability issues worsen
Solution Approach 1:
The patent changes the Poisson's ratio parameter from positive to negative by transforming the microstructure into reentrant configurations. This parameter change enables the material to simultaneously achieve cooling functionality and stress resistance, resolving the contradiction between heat dissipation and stress resistance in high-temperature applications
Solution Approach 2:
The patent creates composite structures combining reentrant microstructures with matrix materials to form NPR materials. These composite structures provide both the cooling pathways needed for heat dissipation and the enhanced mechanical properties required for stress resistance, eliminating the trade-off between these two requirements
2Device complexity
If conventional positive Poisson's ratio materials are used, then material simplicity is maintained, but stress concentration and fluid permeability issues arise
Solution Approach 1:
The patent transforms the Poisson's ratio parameter from positive to negative through microstructural reconfiguration. This fundamental parameter change inverts the material's deformation behavior, causing it to expand laterally when compressed and contract when stretched, thereby eliminating stress concentration while maintaining structural integrity
Solution Approach 2:
The patent employs reentrant curved microstructures with specific geometries that enable the NPR effect. The curved, reentrant configurations distribute stress more uniformly throughout the material, preventing stress concentration points while maintaining overall material simplicity
3Stress or pressure
If reentrant structures are introduced to achieve NPR behavior, then stress distribution is improved, but manufacturing complexity increases
Solution Approach 1:
The patent divides the material into repeating unit cells with reentrant microstructures. This segmentation allows the complex NPR behavior to be achieved through simple, standardized unit cell patterns that can be manufactured using conventional techniques, reducing overall manufacturing complexity while maintaining improved stress distribution
Solution Approach 2:
The patent optimizes the geometric parameters of the reentrant structures (such as reentrant angle, cell size, and wall thickness) to achieve the desired NPR effect while keeping the structures manufacturable. By carefully selecting parameters within practical ranges, the patent balances stress distribution improvement with manufacturing ease
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 zero-porosity Negative Poisson's Ratio structure exhibits low stress values and high structural stiffness, making it suitable for applications like gas turbine components, heat exchangers, and other mechanically and thermally loaded structures without fluid permeability, enhancing performance and reliability.
Implementation Method 1
A zero-porosity structure with a Negative Poisson's Ratio is achieved by arranging structural elements, such as spherical caps or ellipsoidal shapes, in specific tiling patterns that transform the material's behavior from Positive to Negative Poisson's Ratio
Data Source
AI summary
The present concepts include a zero-porosity structure having a plurality of structural elements arranged to provide a negative Poisson's ratio and, further, a new mechanism to generate negative Poisson's ratio is single material, zero-porosity structure.