A study of the vibration isolation performance of a limited phononic crystal vibration isolator based on local resonance theory

Abstract

In this study, a limited phononic crystal vibration isolation (LPCVI) model is constructed based on a vibration isolator used in the field of rail transit, and analyses of the characteristics of the bandgap, the vibration isolation effect, and the vibrational energy transfer of the model are presented. In this paper, the Boltzmann integration theory and the Bloch theorem are used to establish a mathematical model that analyzes the band structure based on the viscoelastic damping of the system. Additionally, by comparing the practical finite periodic structure model and the conventional mass-spring-damping vibration isolation model, explicit forms of the vibration isolation coefficients of the models are derived. It is found that when the external excitation frequency is within the forbidden band range, the vibration isolation coefficient of the LPCVI system with a harmonic oscillator is much smaller than that of the vibration isolation system with a general mass-spring. Furthermore, the Newmark-β integration method is adopted to solve the vibration equation of the LPCVI model. The energy input, distribution, and output of the system are obtained when the energy is under excitation in the forbidden band and bandpass frequencies. It is found that the external excitation does both positive and negative works on the vibration isolation system within a certain period under the action of the central frequency excitation of the forbidden band; therefore, the energy cannot be input into the isolation system. This makes it possible to achieve effective vibration isolation at lower frequencies.

High sensitivity biosensing scheme based on a GHz phononic crystal waveguide

“…We choose the waveguide defect width for the proposed biosensor to be w = 1.3a, since it yields a relatively high quality (Q) factor as well as enough transmission for high sensitivity biosensing. Compared to cavity-type phononic-crystal sensors, 6) the waveguide type can exhibit higher transmission efficiencies because they transfer the energy through the phononic-crystal instead of trapping it inside, which facilitates excitation and detection (as shown by the example of a cavity-type geometry in Fig. S1 of the Supplementary Data).…”

“…2) To control acoustic waves, phononic crystals (PnC) in particular have attracted much attention in the past few decades because they can influence the propagation behavior of sound waves by means of flexible design methodologies based on different shapes, dimensions, and materials. PnC has been applied to waveguides, 3) filters, 4) energy harvesters, 5) vibration isolators, 6) and, notably, sensors, [7][8][9][10][11][12][13] showing great potential. Sensors based on PnC show advantages of high sensitivity, quality factor and target selectivity.…”

Ultra-Wide Bandgap in Two-Dimensional Metamaterial Embedded with Acoustic Black Hole Structures

“…The concept of metamaterials provides novel ideas and methods to the research and applications in wave guiding [11], filtering [12], cloaking [13,14], bandgaps [15][16][17][18], and energy harvesting [19]. Moreover, this fundamental property offers a variety of promising applications in the isolation of vibration and shock waves for a lot of precision equipment and engineering structures [20]. Ruan et al provided a type of spiral phononic crystal for the low-frequency isolation on a ship [21].…”

Long-Term Efficient Control of Structure-Borne Noise Inside Buildings Caused by Underground Railways by Using Novel Damping Fasteners

“…In recent years, a variety of new damping materials have been developed. Xi, Wang, and Zhao used phononic crystal vibration isolators to replace the steel springs in floating slab tracks and improve the vibration isolation performance of the floating slab track (15)(16)(17)(18). Yang et al developed a theoretical method for predicting the dynamic response and damage of railway slab tracks using a periodic structure model (19,20).…”