Mechanical response of negative stiffness truncated-conical shell systems: experiment, numerical simulation and empirical model

As promising materials, the NS mechanical metamaterials bring new alternatives for energy-absorbing materials, but also research challenges in performance prediction considering their large, local deformation. In this paper, numerical and experimental methods were employed to investigate the mechanical properties of the truncated-conical shell element. Also, empirical formulas, which can well predicate the element's response, were developed based on the simulated data. Mechanical responses of the metamaterials, consisted of truncated-conical shells in a periodic arrangement, were investigated through the multilinear model. These prediction models were all verified through the simulations and experiments, and the comparison results indicated that the presented models were applicable in wide parameter range, attributed to a piecewise fitting method. Generally, a comprehensive approach, of general applicability, is presented in this paper to study the NS metamaterial's mechanical response from local to global, and it can be a reference to researches on novel NS metamaterials.