Realization of active metamaterials with odd micropolar elasticity

Area of Science:

• Active Materials
• Metamaterials
• Non-Hermitian Physics

Background:

• Active materials with local sensing and computation exhibit emergent properties.
• Conventional elastic media are typically energy-conserving and lack non-reciprocal properties.

Purpose of the Study:

• To realize a freestanding active metabeam with piezoelectric elements and electronic feed-forward control.
• To investigate the emergent odd micropolar elasticity and its relation to non-Hermitian topology.
• To explore the energy conversion capabilities and tunable vibrational properties of the active metabeam.

Main Methods:

• Fabrication of a freestanding active metabeam incorporating piezoelectric elements.
• Implementation of electronic feed-forward control for dynamic regulation.
• Development of a continuum mechanics approach based on symmetries and conservation laws.
• Analysis of the odd micropolar elasticity, non-Hermitian topological index, and vibrational mode localization.

Main Results:

• The active metabeam exhibits an emergent odd micropolar elasticity, distinct from energy-conserving media.
• The non-reciprocal odd modulus facilitates bidirectional energy conversion between electrical and mechanical domains.
• The sign of the elastic modulus correlates with a non-Hermitian topological index, governing mode localization.
• Tunable phase angles of the active modulus allow control over direction-dependent bending and non-Hermitian vibrational characteristics.

Conclusions:

• The developed active metabeam demonstrates a novel form of elasticity with energy conversion capabilities.
• The findings link odd elasticity to non-Hermitian topology, providing a framework for designing advanced active materials.
• This approach offers potential for creating synthetic biofilaments and membranes with sophisticated feed-forward control mechanisms.