An extended Euler-Bernoulli beam principle in multi-component metamaterial towards tunable Poisson's ratio

In this paper, a multi-component mechanical metamaterial was proposed to achieve tunable nominal modulus and Poisson's ratio to extend the potential and practical applications in smart materials and structures. Based on the Euler-Bernoulli beam theory, a universal model was formulated for the multi-component metamaterial to explore the constitutive relationship between the model parameters and mechanical properties. The theoretical model reveals that the Poisson's ratio of the multi-component metamaterial could be quantitatively regulated over a broad range by manipulating the moduli of its constituent components. On this basis, a bi-component metamaterial composed of polylactic acid (PLA) and thermoplastic polyurethane (TPU), featuring distinct temperature-dependent moduli and geometric configurations, was manufactured and exhibited thermally tunable mechanical behavior. Parametric finite element simulations were conducted to investigate the synergistic effect of temperature-dependent moduli and geometric parameters on the stable mechanical behaviors of the bi-component metamaterial, with the results validated by experimental measurements. This study examines the design principle that combines material parameters (temperature-dependent moduli) and structural parameters (geometric parameters) for the multi-component mechanical metamaterial. The methodologies and insights presented in this paper provide new perspectives and technical approaches for the innovative applications of metamaterials in aerospace, biomedical, and microelectronic fields.