This paper reports upon the design and development of a novel testing rig for the examination of additively manufactured auxetic componentry. By firstly reviewing the key challenges for practical researchers and exploring the range of approaches used to examine auxetic structures, we subsequently introduce a new testing configuration seeking to enhance the existing methods found within the literature. The developed testing configuration includes a novel mechanical design with a new method for component mounting offering advanced control of the boundary condition and a fully developed control interface which facilitates real-time analytics, a range of data acquisitions and integration with a CAD environment. This paper describes both the development of the mechanical design and the development of the control interface by exploring the key design features and documentation of the manufacturing and assembly process. Finally, we discuss how the presented testing configuration offers a new and flexible way of testing auxetic componentry with additional insights offered for future researchers who wish to recreate or adapt the testing setup for their own examinations of additively manufactured componentry.

The exact solutions of Pochhammer — Chree equation for propagating harmonic waves in isotropic elastic cylindrical rods, are analyzed. Spectral analysis of the matrix dispersion equation for the longitudinal axially symmetric modes is performed. Analytical expressions for displacement fields are obtained. Variation of the wave polarization due to variation of Poisson’s ratio for mild auxetics (Poisson’s ratio is greater than -0.5) is analyzed and compared with the non-auxetics. It is observed that polarization of the waves for both considered cases (auxetics and non-auxetics) exhibits abnormal behavior in the vicinity of the bulk shear wave speed.

This paper presents a tunable planar auxetic metamaterial (PAM) for controlling and filtering acoustic waves and provides guidelines for bandgap design of the proposed PAMs. Numerical results for deformed and undeformed PAMs were obtained from several finite element analyses based on Bloch–Floquet theory. The acoustic band structures of the PAMs were calculated with periodic boundaries. Tunable bandgaps in certain frequency ranges were generated by various deformations applied to the PAMs. Wave attenuation in experimental transmission loss at specific frequencies was demonstrated, showing favorable agreement with the bandgaps obtained from numerical calculations. Both the numerical and experimental results indicate that the proposed structure demonstrates great tunability and offers significant advantages over the regular materials for controlling sound wave propagation and filtering sound waves within specific frequency ranges.