Hyper-damping properties of a stiff and stable linear oscillator with a negative stiffness element

Abstract

A simple, stiff, statically and dynamically stable linear oscillator incorporating a negative stiffness element is used as a template to provide a generic theoretical basis for a novel vibration damping and isolation concept. This oscillator is designed to present the same overall static stiffness, the same mass and to use the same damping element as a reference classical linear SDoF oscillator. Thus, no increase of the structure mass or the viscous damping is needed, as in the case of a traditional linear isolator, no decrease of the overall structure stiffness is required as in the case of 'zero-stiffness' oscillators with embedded negative stiffness elements. The difference from these two templates consists entirely in the proper redistribution and reallocation of the stiffness and the damping elements of the system. Once such an oscillator is optimally designed, it is shown to exhibit an extraordinary apparent damping ratio, which is even several orders of magnitude higher than that of the original SDoF system, especially in cases where the original damping of the SDoF system is extremely low. This extraordinary damping behavior is a result of the phase difference between the positive and the negative stiffness elastic forces, which is in turn a consequence of the proper redistribution of the stiffness and the damping elements. This fact ensures that an adequate level of elastic forces exists throughout the entire frequency range, able to counteract the inertial and the excitation forces. Consequently, a resonance phenomenon, which is inherent in the original linear SDoF system, cannot emerge in the proposed oscillator. The optimal parameter selection for the design of the negative stiffness oscillator is discussed. To further exhibit the advantages that such a design can generate, the suggested oscillator is implemented within a periodic acoustic metamaterial structure, inducing a radical increase in the damping of the propagating acoustic waves. The concept may find numerous technological applications, either as traditional vibration isolators, or within advanced composite materials and metamaterials.

Implementation of the Kdamper Concept to Wind Turbine Towers

“…A novel passive vibration isolation and damping concept, KDamper is proposed in Antoniadis et al [1] incorporating negative stiffness elements in the classical Tuned Mass Damper isolation system (TMD), which can exhibit extraordinary damping properties, without presenting the drawbacks of the traditional linear oscillator, or of the 'zero-stiffness' designs. This oscillator is designed to present the same overall (static) stiffness as a traditional reference original oscillator.…”

“…Although the proposed oscillator incorporates a negative stiffness element, it is designed to be both statically and dynamically stable. Once such a system is designed according to the approach proposed in (Antoniadis et al, 2015 [1]), it is shown to exhibit an extraordinary damping behaviour. Figure 1 presents the basic layout of the fundamental vibration isolation and damping concepts to be considered.…”

Parameter Optimization of the Kdamper Concept in Seismic Isolation of Bridges Using Harmony Search Algorithm

“…Combining the beneficial characteristics of both aforementioned typed of seismic isolation device, a novel passive vibration isolation and damping configuration is introduced, based on the KDamper concept introduced by Antoniadis et al [23]. The proposed device incorporates a negative stiffness element, which can exhibit extraordinary damping properties, without the drawbacks of TMDs or QZS oscillators.…”

“…However, the KDamper overcomes the sensitivity problems of TMDs as the tuning is mainly controlled by the negative stiffness element's parameters. Once such a system is designed according to the approach proposed in [23], it is shown to exhibit an extraordinary damping behaviour. A first approach to the implementation of the KDamper concept for the seismic isolation of a typical bridge can be found in [24].…”

Quantification of Guided Wave Interaction Effects With Localised Structural Nonlinearities in Complex, Composite Structures

“…The vibration of a uniform waveguide through the WFE technique was investigated in [32,33]. The WFE method has recently found applications in predicting the vibroacoustic and dynamic performance of composite panels and shells [34,35,36,37,38,39,40] , with pressurized shells [41,42] and complex periodic structures [43,44,45,46] having been investigated. The variability of acoustic transmission through layered structures [47,48], as well as wave steering effects in anisotropic composites [49] have been modelled through the same methodology .…”