Non-planar Shearing Auxetic Structures for Deployable Engineering
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Solution Overview
Problem
Conventional auxetic structures are limited to planar surfaces and cannot efficiently deploy on non-planar shapes like spheres, spheroids, and cylinders, lacking the ability to switch between rigid and compliant states, which hinders their application in fields such as aerospace, robotics, and deployable structures.
Innovation Solution
Development of non-planar shearing auxetic structures that can tile over compact surfaces, featuring handedness to expand only in response to net shear in one direction, allowing for self-locking deployable structures and actuators with varying degrees of freedom, utilizing repeating unit cells with pivot joints and living hinges or mechanical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional auxetic structures are used, then they can be manufactured with simple unit cells, but they are limited to planar surfaces and cannot deploy on non-planar shapes
Solution Approach 1:
The patent applies curvature by developing auxetic structures that can be tiled over non-planar surfaces including spheres, spheroids, cylinders, and capsules. The unit cells are designed with geometric configurations that accommodate curved surfaces while maintaining the auxetic properties, allowing the structure to adapt to various three-dimensional geometries rather than being limited to flat planes.
Solution Approach 2:
The patent transitions from two-dimensional planar auxetic structures to three-dimensional non-planar configurations. By adding the third dimension and enabling the structure to wrap around curved surfaces, the invention achieves versatility across different geometric forms while preserving the fundamental auxetic behavior of the unit cells.
2Stability of the object's composition
If conventional auxetic structures are used, then they have predefined rigidity and stiffness, but they cannot switch between rigid and compliant states
Solution Approach 1:
The patent implements dynamic rigidity switching by designing unit cells with movable joints and flexible connections that allow the structure to transition between rigid and compliant states. The unit cells can change their internal configuration in response to applied forces, enabling the overall structure to adapt its stiffness properties rather than maintaining a fixed rigidity.
Solution Approach 2:
The patent changes the mechanical parameters of the structure by varying the internal angles and configurations of the unit cells. Through controlled deformation of the unit cell geometry, the structure can switch between different mechanical states, including rigid and compliant configurations, allowing dynamic adjustment of rigidity and stiffness properties.
3Stability of the object's composition
If conventional auxetic structures are used, then they deform in a predefined manner, but they lack the ability to convert rotational motion into translation, bending, or volume expansion
Solution Approach 1:
The patent enables dynamic motion conversion by designing unit cells with movable joints and flexible connections that can transform different types of motion. The structure can convert rotational motion into translational movement, bending, or volume expansion through the coordinated deformation of unit cells, providing versatile actuation capabilities rather than being limited to predefined deformation patterns.
Solution Approach 2:
The patent achieves multi-functionality by designing unit cells that can perform multiple deformation modes and motion conversions simultaneously. The same unit cell structure can facilitate rotational-to-translational conversion, bending, and volume expansion, making the auxetic structure capable of performing diverse functions through a single unified design.
4Adaptability or versatility
If non-planar shearing auxetic structures are developed, then they can tile over compact surfaces and provide flexibility, but they increase structural complexity
Solution Approach 1:
The patent applies segmentation by dividing the complex non-planar structure into repeating modular unit cells that can be independently designed and assembled. These standardized unit cells can be tiled across different surface geometries, allowing complex three-dimensional structures to be constructed from simple, reusable components that maintain auxetic properties.
Solution Approach 2:
The patent implements nesting by creating hierarchical structures where unit cells are arranged within larger modular assemblies that can be nested or stacked to form complex three-dimensional configurations. This modular nesting approach allows complex surfaces to be built up from simpler repeating units, managing structural complexity through organized modularity.
Data Source
AI summary
Non-planar shearing auxetic structures, devices, and methods are provided herein. In some embodiments, a non-planar shearing auxetic structure can include a mathematically compact surface with an auxetic pattern of repeating unit cells. The shearing auxetic structure can have a contracted configuration and an expanded configuration, and, when in the compact configuration, can be configured to move to the expanded configuration while generating a net shear on the surface. Shearing auxetic structures can have handedness and, in some embodiments, multiple handed shearing auxetic structures can be joined to create rigid or semi-rigid composite structures, e.g., by arranging differently-handed structures concentrically wherein two or more structures lock against each other. Handed shearing auxetic structures can also provide actuators to convert rotation or other motion to translation, volume expansion, bending, twisting, etc. These structures have many applications, e.g., deployable structures such as pressure vessels, space habitats, fluid carrying vessels, soft robotics, toys, etc.