Design and mechanical characterisation of piezoelectric fibre-driven variable-Poisson’s-ratio honeycomb structures

Conventional mechanical metamaterials typically have fixed geometries, which limits their adaptability to complex service conditions. To address this limitation, this study proposes an electrically tuneable honeycomb structure with a variable Poisson’s ratio, achieved by integrating macro fibre composite (MFC) actuators into the cell walls. A multi-field coupled analytical model was developed to describe the voltage-induced bending deformation, effective Poisson’s ratio, in-plane equivalent elastic modulus, and out-of-plane bending stiffness of the structure. The underlying mechanism of the electrically driven geometric reconfiguration was systematically revealed. By switching the polarity of the applied voltage, the cell walls undergo a reversible transition between the convex and concave configurations, enabling controllable switching between auxetic (negative) and conventional (positive) Poisson’s ratio regimes. Experimental results and finite element simulations demonstrate good agreement with the theoretical predictions, with deviations consistently within 5%. Notably, the Poisson’s ratio can be reversibly switched between −11.5 and a positive value under ±1200 V. Although the out-of-plane bending stiffness is significantly tuned, the longitudinal equivalent elastic modulus varies by less than 3%, demonstrating an effective decoupling between deformation-mode regulation and axial load-bearing capacity. The proposed MFC-driven honeycomb structure provides a feasible strategy for programming mechanical properties through electrical stimuli, thereby offering a viable pathway for developing next-generation adaptive structures for aerospace, robotics, and vibration control applications.