# Auxetic behavior and acoustic properties of microstructured piezoelectric strain sensors

## TL;DR

This paper investigates the mechanical, piezoelectric, and acoustic properties of auxetic microstructured lattice materials for strain sensors, using computational homogenization and dispersion analysis to identify band gaps and sensor designs.

## Contribution

It introduces a first-order homogenization method for electro-mechanical coupling in auxetic piezoelectric lattices and explores their acoustic band gaps for sensor applications.

## Key findings

- Identification of acoustic band gaps in auxetic piezoelectric structures
- Design concepts for in-plane and out-of-plane strain sensors
- Demonstration of auxetic topology's influence on acoustic and piezoelectric properties

## Abstract

The use of multifunctional composite materials adopting piezo-electric periodic cellular lattice structures with auxetic elastic behavior is a recent and promising solution in the design of piezoelectric sensors. In the present work, periodic anti-tetrachiral auxetic lattice structures, characterized by different geometries, are taken into account and the mechanical and piezoelectrical response are investigated. The equivalent piezoelectric properties are obtained adopting a first order computational homogenization approach, generalized to the case of electro-mechanical coupling, and various polarization directions are adopted. Two examples of in-plane and out-of-plane strain sensors are proposed as design concepts. Moreover, a piezo-elasto-dynamic dispersion analysis adopting the Floquet-Bloch decomposition is performed. The acoustic behavior of the periodic piezoelectric material with auxetic topology is studied and possible band gaps are detected.