Soft and Stiff Simplex Tensegrity Lattices as Extreme Smart Metamaterials

Area of Science:

• Materials Science
• Mechanics of Materials
• Computational Solid Mechanics

Background:

• Cellular metamaterials offer tunable mechanical properties.
• Tensegrity structures provide unique load-bearing capabilities.
• Understanding the behavior of complex metamaterials is crucial for advanced applications.

Purpose of the Study:

• To evaluate novel cellular metamaterials based on a tensegrity pattern.
• To investigate the mechanical properties and deformation modes of these metamaterials.
• To classify the metamaterials within the framework of extreme materials.

Main Methods:

• Construction of metamaterials from simplex modules forming supercells.
• Utilizing a continuum model based on strain energy equivalence.
• Incorporating nonlinearities related to self-equilibrated forces in tensegrity structures.
• Analyzing eigensolutions of equivalent elasticity matrices.

Main Results:

• Mechanical properties are controllable via self-equilibrated forces and member properties.
• Six representative deformation modes (stiff, soft, medium extensional; high/low shear) were identified.
• Lattices were classified as extreme metamaterials, specifically unimode or nearly bimode.

Conclusions:

• Tensegrity-based cellular metamaterials represent a novel class of extreme materials.
• The developed continuum model accurately captures their qualitative properties and nonlinear behavior.
• The identified deformation modes and classification provide insights for material design and application.