Zero Poisson's Ratio Structure for Stress Control
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Solution Overview
Problem
Existing technologies face challenges in designing complex structures with a near-zero Poisson's ratio, which is essential for controlling stress and mechanical noise in fields like electronic circuits and soft robots, as they struggle to fabricate monolithic and anisotropic structures with effective stress confinement.
Innovation Solution
A novel structure with a zero Poisson's ratio is designed, comprising a central pillar with radially extending branched connectors, where the angles between the central pillar, segmental portions, and legs are variable, allowing for minimal horizontal displacement under pressure, and can be arranged in planar or three-dimensional forms using 3D printing or stacking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If conventional methods are used to control stress by modifying mechanical modulus of specific parts, then stress control of specific parts is achieved, but it is difficult to fabricate monolithic structures and anisotropic structures
Solution Approach 1:
The structure is divided into multiple unit cells, each comprising a central pillar and branched connectors. These unit cells can be independently designed and then assembled into larger monolithic structures through 3D printing or stacking, enabling both stress control and complex fabrication.
Solution Approach 2:
The invention transitions from 2D planar arrangements to 3D stacked configurations of unit cells. This dimensional transformation enables the creation of complex monolithic structures with controlled stress distribution properties while maintaining manufacturability through additive manufacturing processes.
2Stress or pressure
If conventional methods are used to control stress by modifying mechanical modulus of specific parts, then stress control of specific parts is achieved, but it is difficult to fabricate anisotropic structures
Solution Approach 1:
Each unit cell is designed with specific geometric characteristics (central pillar and branched connectors at defined angles) that provide localized stress control properties. By arranging these standardized units in different configurations, anisotropic structures with direction-dependent mechanical properties can be fabricated.
Solution Approach 2:
The unit cell structure serves multiple functions: it acts as a stress control element, an anisotropic structural unit, and a modular component for 3D assembly. This multi-functionality enables the simultaneous achievement of stress control and anisotropic structure fabrication without requiring separate design processes.
3Stress or pressure
If existing zero Poisson's ratio structures are used, then stress spreading is reduced, but it is difficult to design complex structures and confine stress
Solution Approach 1:
The complex structure is segmented into repeating unit cells with simple geometries (central pillar and branched connectors). This segmentation allows the complex overall structure to be designed through modular assembly while maintaining the simple stress-spreading characteristics of individual units.
Solution Approach 2:
The branched connectors are designed with variable angles that can dynamically adjust under applied load. This dynamic behavior enables the structure to adapt to different stress states, providing both stress spreading reduction and effective stress confinement in complex configurations.
4Stress or pressure
If existing zero Poisson's ratio structures are used, then stress spreading is reduced, but it is difficult to confine stress
Solution Approach 1:
The structure utilizes 3D stacking of unit cells to achieve stress confinement in multiple dimensions. By arranging unit cells in vertical stacks with controlled geometries, stress can be confined in the vertical direction while maintaining horizontal stress spreading characteristics, enabling complex stress control functionality.
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 structure effectively controls stress and mechanical noise, enabling the creation of complex mechanical designs that do not expand under pressure, suitable for sensitive electronic devices and robotics, while allowing for stress transmission and contraction through combined Poisson's ratio structures.
Implementation Method 1
A Poisson's ratio close to zero allows stress from mechanical impact to spread to a material in a reduced manner. Implementation of the near-zero Poisson's ratio may be used in various fields.
Implementation Method 2
due to a force pressing the central pillar, each of an angle between the central pillar and the first segmental portion, an angle between the first segmental portion and the second segmental portion, and an angle between the second segmental portion and the leg is variable
Data Source
AI summary
Disclosed is a zero Poisson's ratio structure including a central pillar; at least two branched connectors extending radially from a lower end of the central pillar, wherein each of the branched connectors includes: a first segmental portion extending inclinedly upwardly or downwardly from the central pillar; and a second segmental portion extending inclinedly downwardly or upwardly from a distal point of the first segmental portion, wherein the extension directions of the first and second segmental portions are opposite to each other; and each leg extending perpendicularly downwardly from a distal point of each of the second segmental portions, wherein due to a force pressing the central pillar, each of an angle between the central pillar and the first segmental portion, an angle between the first segmental portion and the second segmental portion, and an angle between the second segmental portion and the leg is variable.