Effectiveness and robustness of an asymmetric nonlinear energy sink‐inerter for dynamic response mitigation

Abstract

Nonlinear energy sinks (NESs) have outperformed tuned mass dampers in mitigating undesired responses against changes in structural frequencies. However, the dilemma of gaining frequency robustness at the cost of energy sensitivity as well as the large masses of devices required for civil engineering structures impede the applications of existing NESs. To solve the issue of lacking energy robustness and take advantage of inerters to reduce physical mass, an asymmetric NES‐inerter (Asym NESI) is developed in this study. This passive inerter‐based nonlinear mass damper is configured based on an energy‐robust NES with an inerter added between the auxiliary mass and a fixed point. The paper commences with the formulation of the Asym NESI through mathematical derivations. Then an Asym NESI is designed and evaluated on a three‐story structure in comparison with other counterpart mass dampers. The effectiveness of the Asym NESI can be attributed to its unique dynamics which are revealed analytically using the harmonic balance method through free vibrations and harmonically forced vibrations. The ensuing numerical validations show that due to the integrated linear and nonlinear dynamics of the Asym NESI, the proposed device exhibits strong robustness against changes in both structural frequency and energy level. Moreover, driven by the large inertial effect induced by the auxiliary inerter, the Asym NESI shows flexibility in choosing a practical installation location without sacrificing excellent control capacity. Importantly, the benefits of the Asym NESI are further confirmed by the responses subjected to a suite of ground motions. This study provides analytical insights into the effectiveness and robustness of Asym NESIs and demonstrates substantial performance enhancement by the inerter in structural response mitigation.

Dynamic analysis of 1-dof and 2-dof nonlinear energy sink with geometrically nonlinear damping and combined stiffness

“…[21][22][23]. It has special advantages in vibration suppression, which also provides a new idea and reference index for optimizing the design of NES [24,25].…”

An inerter‐enhanced asymmetric nonlinear energy sink for response mitigation of structures subjected to harmonic and seismic ground excitations

“…In the previous study, 42 the fundamental dynamics of standalone ANESI (without the primary structure) were revealed analytically. The analytical results declare that the ANESI exhibits linear‐like dynamics when the displacement is within a certain range.…”

“…Note that the ANESI model presented in Wang et al 42 only considers the damping element between the primary structure and the auxiliary mass (termed as the mass damping element). However, due to the friction and backlash that inevitably exist in the motion transmission system, damping should also be considered in the inerter part.…”

“…Note that TMDs and TIDs are actually two special cases of TMDIs with inertance and mass set to zero, respectively. Following the same inerter arrangement, CNES‐inerters ( CNESIs ) 41 and ANES‐inerters ( ANESIs ) 42 are also developed based on CNESs and ANESs, respectively. Studies show that mass dampers with inerter can achieve excellent control effect that are competitive to their counterparts without inerter but with a much lighter physical mass involved and much less space demand required.…”

Wind‐ and sea wave‐induced response mitigations of offshore wind turbines using track nonlinear energy sinks

“…Lu et al 41 provided a comprehensive review on the development of various NESs. NESs were recently combined with shape memory alloy (SMA) spring and inerter to form SMA- 42 and inerter-based [43][44][45] NESs, respectively, to improve the control performance of NESs further. The effectiveness and robustness of NESs against changes in natural frequencies of the host structure have been experimentally and numerically investigated.…”