Mechanical and electrical strain response of a piezoelectric auxetic PZT lattice structure

A two-dimensional auxetic lattice structure was fabricated from a PZT piezoceramic. Tape casted and sintered sheets with a thickness of 530 μm were laser cut into inverted honeycomb lattice structure with re-entrant cell geometry (θ = −25°) and poling direction oriented perpendicular to the lattice plane. The in-plane strain response upon applying an uniaxial compression load as well as an electric field perpendicular to the lattice plane were analyzed by a 2D image data detection analysis. The auxetic lattice structure exhibits orthotropic deformation behavior with a negative in-plane Poisson's ratio of −2.05. Compared to PZT bulk material the piezoelectric auxetic lattice revealed a strain amplification by a factor of 30–70. Effective transversal coupling coefficients ${d^{al}}_{31}$ of the PZT lattice exceeding 4 × 10³ pm V⁻¹ were determined which result in an effective hydrostatic coefficient ${d^{al}}_h$ 66 times larger than that of bulk PZT. (paper)