Super Damping of Mechanical Vibrations

Abstract

We report the phenomenon of coherent super decay (CSD), where a linear sum of the displacement of several damped oscillators can collectively decay much faster than the individual ones in the first stage, followed by stagnating ones after more than 97% of the energy has been dissipated. The parameters of the damped oscillators for CSD are determined by the process of response function decomposition, which is to use several slow decay response functions to approximate the response function of a fast decay resonator. Evidence established in experiments and in finite element numerical simulations not only strongly supported the numerical investigations, but also uncovered an unexplored region of the tuned mass damper (TMD) parameter space where TMD’s with total mass less than 0.2% of a stainless steel plate can damp its first resonance at 100 Hz up to a damping ratio of 4.6%. Our findings also shed light onto the intriguing underline relationships between complex functions with different singular points.

Folded sheet resonators that aim at low frequency attenuation of surface elastic waves in solids

“…scitation.org/journal/jap and 2.0 s, respectively, after the initial impact excitation is applied. 30 Four major resonances at 7.2, 9.5, 51.8, and 100.9 Hz can be clearly identified. The peak amplitudes of the four resonances at different delayed moments 30 are shown in the remaining four figures after Fig.…”

“…Decorated membrane resonators (DMR's) 29 can serve as compact and lightweight miniature dampers with single or multiple working frequencies. 27,28,30 The photo of a typical one is shown in the right half of Fig. 1(a), which consists of a rubber membrane (purple in color) mounted on a rigid circular ring about 25 mm in diameter and decorated by a rigid metallic disk.…”

“…Using membranes to provide the restoring forces, DMR's with resonant (working) frequency ω 0 around 100 Hz while having total weight about 1.5 g have been demonstrated. 27,28,30 Furthermore, they can be effectively treated as equivalent TMD's for their damping effect on any primary object of sufficiently large size. 27,28,30 Due to the limited lifespan of the latex rubber membranes, DMR's with metallic membranes are preferred if they are to last for decades.…”

“…27,28,30 Furthermore, they can be effectively treated as equivalent TMD's for their damping effect on any primary object of sufficiently large size. 27,28,30 Due to the limited lifespan of the latex rubber membranes, DMR's with metallic membranes are preferred if they are to last for decades. The DMR-like dampers were reported in our previous work; 23 here, it is a laboratory sample containing a stainless steel sheet about 0.1 mm in thickness folded into a zigzag pattern as the replacement of the elastic rubber membrane.…”

Loss Factor Behavior of Thermally Aged Magnetorheological Elastomers

“…Mechanical vibrations, which are caused by oscillations in mechanical dynamic systems such as in manufacturing processes or in-home appliances are an unwanted phenomenon in our daily lives [1]. Moreover, these mechanical vibration forms can lead to excessive noise, which have a negative impact on labor safety, manufacturing efficiency, and productivity [2,3].…”