Application of Geometrically Nonlinear Metamaterial Device for Structural Vibration Mitigation

Abstract

One of the major challenges encountered by civil structures throughout their life cycle pertains to exposure to dynamic loadings, with earthquakes representing an extreme case of such a load. The frequency content of a dynamic excitation is of primary importance not only because of the potential resonance it induces but also due to limitations that arise for the capabilities of vibration mitigation devices. A recently emerging technology for civil structure applications includes the development of metamaterial configurations. These are structures, which are formed by periodic arrangement of a fundamental component design, termed the unit cell. They can offer impressive filtering properties within specific frequency ranges, the so-called bandgaps. Considering the low-frequency content of earthquake excitation, a design that features a bandgap in the lower-frequency range is required. In this study, the potential of a geometrically nonlinear design for vibration mitigation purposes is investigated for lowering of the corresponding bandgap. The system consists in the periodic arrangement of nonlinear unit cells, each including a triangular arch configuration, which under large displacement considerations can produce not only geometrically nonlinear behavior but also negative stiffness effects. Analytical derivations result to the determination of the amplitude-dependent bandgap of the system. The proposed configuration is attached to a target structure subjected to protection. An assessment on the capabilities of the device toward this direction was performed via numerical analyses, revealing considerable effectiveness. Acceleration response and energy-related measures are considered in the evaluation of the system’s performance. An additional potential, which the proposed configuration can offer, refers to the applicability of the system for retrofitting purposes of existing structures. It is concluded that the system can offer significant vibration mitigation capabilities, while further study and development of the design, taking into consideration constructability limitations, can lead to an efficient passive vibration absorption device.