3D Shellular Metamaterial With Multistable Perforated Hinges
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Solution Overview
Problem
Current low-density materials lack tunable properties and durability under large forces and deformation, limiting their applications in load-bearing and energy absorption applications.
Innovation Solution
Development of a 3D multistable shellular metamaterial with staggered perforations that form hinges, enabling multiple stable states and enhanced energy dissipation through snap-through and snap-back instabilities, and self-contact mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If low-density materials are used, then weight is reduced, but strength and durability under large forces deteriorate
Solution Approach 1:
The material is segmented into discrete unit cells arranged in a periodic lattice structure. Each unit cell contains a shell with perforations that can independently snap between stable states, allowing the material to maintain low density while distributing mechanical loads across multiple discrete elements rather than requiring a monolithic high-strength structure.
Solution Approach 2:
The material transitions from a static structure to a dynamic one where the shell perforations can snap between multiple stable states. This dynamic capability allows the material to adapt its stiffness and strength characteristics in response to applied forces, enabling low-density material to tolerate large forces through progressive structural reconfiguration rather than relying solely on material strength.
2Weight of moving object
If low-density materials are used, then weight is reduced, but ability to tolerate large deformation deteriorates
Solution Approach 1:
The shell perforations are designed to snap between multiple stable states (bistable or multistable), enabling the material to undergo large deformations while maintaining structural integrity. The dynamic reconfiguration of the perforations allows the material to absorb and dissipate energy during deformation, tolerating large shape changes without failure while keeping the overall material density low.
Solution Approach 2:
The material's effective mechanical properties (stiffness, strength, stability) are changed by altering the snap state of the shell perforations. By controlling which perforations are in which stable state, the material can adapt its parameters to tolerate large deformations when needed, while maintaining low density as a fundamental structural characteristic.
3Ease of manufacture
If conventional material design is used, then manufacturing is simple, but tunable properties are limited
Solution Approach 1:
The material's properties are tuned by changing geometric parameters of the unit cells and shell perforations (size, shape, distribution, number of stable states) rather than changing the base material itself. This allows extensive property customization while maintaining compatibility with standard additive manufacturing processes, achieving both ease of manufacture and tunable properties.
Solution Approach 2:
The material is divided into repeating unit cells with specific perforation patterns. This segmentation allows independent optimization of each unit cell's geometry to achieve desired macroscopic properties, while the periodic structure maintains manufacturing simplicity through repetition. Different unit cell designs can be selected or combined to tune overall material behavior.
4Loss of energy
If multistable shellular metamaterial with staggered perforations is used, then energy dissipation is enhanced, but device complexity increases
Solution Approach 1:
The complex multistable behavior is achieved by segmenting the structure into unit cells with staggered perforations. Each perforation acts as an independent energy-dissipating element that can snap between stable states. The staggering arrangement ensures that not all perforations snap simultaneously, creating a progressive energy dissipation mechanism that enhances damping while keeping individual unit cells relatively simple.
Solution Approach 2:
The design merges the shellular material structure with multistable mechanism functionality and staggered perforation patterning into a single integrated structure. This combination achieves enhanced energy dissipation through the coupled effects of shell bending, perforation snapping, and staggered configuration, without requiring separate components or complex assembly procedures.
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 multistable shellular metamaterials exhibit strong rigidity and enhanced energy dissipation, enabling multidirectional load-bearing capabilities and potential applications in soft robotics, shape morphing, and reusable energy absorbers/dampers.
Implementation Method 1
certain shellular snapping motifs with elliptical perforations exhibit mechanical bistability. To bring the concept of multistability to a single snapping motif, we develop multistable shellular snapping motifs by introducing multilayer staggered perforations that form hinges and facilitate local instability.
Implementation Method 2
Harnessing snap-through and snap-back instabilities and self-contact mechanism, the introduced multistable perforated shellulars exhibit strong rigidity both in loading and unloading and enhanced energy dissipation.
Implementation Method 3
a section of the shell extending between adjacent staggered perforations defines a hinge, and the shell bends and twists about the hinge between the first structural state and the second structural state
Implementation Method 4
Harnessing snap-through and snap-back instabilities and self-contact mechanism, the introduced multistable perforated shellulars exhibit strong rigidity both in loading and unloading and enhanced energy dissipation.
Data Source
AI summary
A shell-based material, also referred to as a shellular or a shell-based mechanical metamaterial, is comprised of a plurality of unit cells that are each made of a curved shell, and contain at least one perforation on their snapping motif. The shell-based material has a predetermined number of structural stable states based on the snapping motif and on the at least one perforation. The predetermined number of structural stable states including a first structural stable state, for example an unloaded initial state, and a second structural stable state being different from the first structural stable state.