Vibration Energy Dissipation Research Articles

Vibrational couplings and energy transfer pathways of water\u2019s bending mode

Coupling between vibrational modes is essential for energy transfer and dissipation in condensed matter. For water, different O-H stretch modes are known to be very strongly coupled both within and between water molecules, leading to ultrafast dissipation and delocalization of vibrational energy. In contrast, the information on the vibrational coupling of the H-O-H bending mode of water is lacking, even though the bending mode is an essential intermediate for the energy relaxation pathway from the stretch mode to the heat bath. By combining static and femtosecond infrared, Raman, and hyper-Raman spectroscopies for isotopically diluted water with ab initio molecular dynamics simulations, we find the vibrational coupling of the bending mode differs significantly from the stretch mode: the intramode intermolecular coupling of the bending mode is very weak, in stark contrast to the stretch mode. Our results elucidate the vibrational energy transfer pathways of water. Specifically, the librational motion is essential for the vibrational energy relaxation and orientational dynamics of H-O-H bending mode.

Homogenous asymptotic analysis on vibration energy dissipation characteristics of periodical honeycomb reinforced composite laminate filled with viscoelastic damping material

In this paper, free transverse vibration energy dissipation properties of honeycomb reinforced composite laminated structures are studied. By applying the homogenous asymptotic method (HAM) and representative unit cell (RUC) approach, considering the frequency- and temperature-dependent properties of the viscoelastic damping material (VDM), the constitutive equations of the laminated composite structure is obtained. Based on the transverse wave energy propagation and transmission theory in solid structures, the structural loss factor (SLF) of the composite structure can be ultimately determined, which is a frequency- and temperature-dependent variable according to the same properties of VDM’s physical parameters that were applied. Several geometry factors including the thickness of the VDM layer, the width and the inner angle of the honeycomb reinforcements, influence on the vibration energy dissipation characteristics of the composite structure are investigated qualitatively and quantitatively. The results are validated by the Galerkin method based asymptotic approach, which shows consistency with each other, especially when the external excitation frequency larger than 500 Hz in the considered frequency ranges.

Design of a tuned mass damper for damped structures using an orthogonal-function-based equivalent linearization method

One of the most popular strategies of dissipating vibration energy in engineering structures is to use vibration absorbers. The selection of optimum absorber parameters is extremely important, especially for tuned mass dampers (TMD). Various approximate and numerical methods have been proposed to determine the optimum tuning ratio of a TMD attached to a damped linear structure, of which the application is limited either to lightly damped structures or specific forms of external excitation. In particular, the latter constrains the implementation of these existing methods to many practical engineering problems where the external excitations are typically random. In the current study, a new approach of identifying the optimum tuning ratio of a TMD in a damped primary linear structure is proposed based on an orthogonal-function-based equivalent linearization (EL) method. The effectiveness of the proposed TMD design approach is evaluated by numerical examples and two benchmark buildings. Results show that the proposed method cannot only accurately choose the optimum parameters of a TMD, but is also applicable to a structure having a relatively high mass and/or damping ratio and is subjected to random external excitations. The proposed method is an alternative approach to tune the TMD for damped structures, in methodological terms.

Influence of squeeze film damping on quality factor in tapping mode atomic force microscope

The micro-cantilever is one of the crucial components of atomic force microscopy in tapping mode (TM-AFM). Therefore, a thorough dynamic analysis of cantilevers is very important to further enhancing the performances of TM-AFM. In general, the quality factor can be used to characterize the energy dissipation of the micro-cantilever. In order to examine the mechanism of squeeze film damping on the vibration energy dissipation of micro- cantilevers, three types of micro-cantilevers with different tips, i.e. (1) tipless; (2) spherical; and (3) conical tips, were innovatively designed in this paper. The theoretical models of the three types of probes are established, and the simulation results of pressure and quality factor are given. The quality factor varying with the tip-sample distance is obtained by tune experiment method. Through the comparison of theory and experiment, the shortcomings of the theoretical model are analyzed and the contribution of the conical tip to the squeeze film damping is explored. This study is of great significance to understand the cantilever dynamics in the air at the micro-nano scale.

Influence of Core Thickness and Boundary Condition on the Modal Characteristics of Composite Structure with Metallic Damping Core

To reduce the vibration of the plate-like structure under different boundary conditions, an all-metal damping composite structure was proposed, and its damping layer was entangled metallic wire material (EMWM). A series of quasi-static compression tests were carried out to investigate the damping property of the EMWM layer. A modal test system was set up to evaluate whether the EMWM could dissipate vibration energy. The evaluation results showed that the displacement deviation between the baseplate and constraining plate of the structure was large enough and the EMWM could dissipate vibration energy in the form of friction. The modal characteristics of the composite structure with different core thicknesses under different boundary conditions were researched in this paper by experimental modal tests. The outcomes showed that the damping ratio of the structure would be significantly improved by adding EMWM and constraining plate. The larger the thickness of the core thickness is, the larger the damping ratio and vibration reduction performance of the composite structure are. This paper provides a new technical way for the damping design of high temperature plate structure.

Design and Simulation of a Damper with Negative Stiffness for Vibration Mitigation from Drilling Equipment to a Semi-Submersible Platform

A negative-stiffness damper (NSD) that incorporates eccentric columns and high-stiffness springs is proposed for vibration mitigation from drilling equipment to a semi-submersible platform. Eccentric columns are considered as negative-stiffness elements, which can provide high static stiffness and achieve negative stiffness with hysteresis energy dissipation caused by buckling mode transition under dynamic conditions. With the assistance of high-stiffness springs, the damper possesses a hysteresis loop that can dissipate vibration energy and mitigate responses. Firstly, the hysteresis characteristics and negative stiffness of eccentric columns are analyzed. Then, the design principle of the NSD is derived, and several characteristics required for applications are investigated. In addition, an NSD system is designed for a target drilling mud pump based on measured data, and the mitigation performance is analyzed by comparing the vibration responses between cases of the proposed NSD system and the steel pedestal. The results demonstrate that the proposed system can effectively reduce the width of affected coverage and the magnitudes of vibration responses. The investigations performed in this paper not only provide the design principle of the new damper, but also prove the great potential of the proposed damper in vibration mitigation from drilling equipment to the hull of the platform.

Dynamic behavior of laterally loaded caisson foundations based on different cushion types: an experimental and theoretical study

Bridge foundations located in deep water are usually subjected to horizontal dynamic loads and moments which may be caused by the wind, waves, earthquake, and the possibility of boat crashing or vehicle braking. Caisson foundations based on gravel or sand cushions are a new type of deep-water foundation for bridges, suitable for meizoseismal areas. In this paper, harmonic horizontal excitation tests for the study of the lateral dynamic response of caisson foundations based on cushion layers are described. Different lateral loads and two different cushion types are considered. The results show that the lateral dynamic responses of caisson foundations based on sand and gravel cushions both show strong nonlinear characteristics, and the resonant frequency of the foundation decreases with the increase of the excitation force. The dynamic displacement of a foundation based on a sand cushion is far less than that based on a gravel cushion, and the rate of decrease of the resonant frequency of a foundation based on a gravel cushion is faster than that of a foundation based on a sand cushion under the same conditions. Under dynamic loading the gravel cushion can more effectively dissipate vibration energy and isolate the vibration, than the sand cushion can. A simplified nonlinear analysis method is proposed to simulate the lateral dynamic response of caisson foundations, and the predicted response shows a reasonable match with the results observed in laboratory tests. Scaling laws have also been applied in this small-scale vibration model test to predict the dynamic behavior of the prototype foundation.

Interfacial Vibrational Dynamics of Ice Ih and Liquid Water.

Insights into energy flow dynamics at ice surfaces are essential for understanding chemical dynamics relevant to atmospheric and geographical sciences. Here, employing ultrafast surface-specific spectroscopy, we report the interfacial vibrational dynamics of ice Ih. A comparison to liquid water surfaces reveals accelerated vibrational energy relaxation and dissipation at the ice surface for hydrogen-bonded OH groups. In contrast, free-OH groups sticking into the vapor phase exhibit substantially slower vibrational dynamics on ice. The acceleration and deceleration of vibrational dynamics of these different OH groups at the ice surface are attributed to enhanced intermolecular coupling and reduced rotational mobility, respectively. Our results highlight the unique properties of free-OH groups on ice, putatively linked to the high catalytic activities of ice surfaces.

Рассеяние энергии в приводной цепи при ее поперечных колебаниях как струны с закрепленными концами

Chain transmissions are widespread in drives of machines used for various industrial purposes. In order to study drive dynamics, it is important to know the dissipative characteristics of its components and gears. However, the information on the damping ability of chain transmissions in research and technical literature is limited and fragmented, which makes the topic of this work, dedicated to the study of energy dissipation in transverse vibrations of chain transmission branches, of great current interest. The objective of this work was to study and determine the quantitative characteristics of energy dissipation in a drive chain experiencing the most common form of transverse vibrations as a string with fixed ends, which is characteristic of transmissions with large masses of sprockets and parts attached to them. To achieve this objective, a mathematical model of the dissipation of vibrational energy was developed using a method of estimating energy losses due to friction when parts of the chain’s hinge joint slip in a compressed contact. Engineering formulas for calculating energy dissipation per cycle of vibrations and absorption coefficient were obtained. The adequacy of the developed model and the obtained calculation formulas was confirmed by the results of the experimental determination of the absorption coefficients of the chain using the method of free damped vibrations. The results of the study allow us to conclude that chain transmissions have an increased damping capacity, and to determine the influence of transmission parameters and the oscillatory process on it.

Performance Analysis of a Novel Magnetorheological Damper with Displacement Self-Sensing and Energy Harvesting Capability

External sensors are vulnerable to the external magnetic field, temperature, noise, and other factors in the semi-active control system based on magnetorheological (MR) damper, which not only reduces the reliability and stability but also increases the complexity, installation space, and system cost. Meanwhile, mechanical energy is generally dissipated as heat due to the friction between the cylinder and damper piston of the MR damper. To further broaden the applications of MR damper, it is essential to maintain excellent functions when the power supply is cut off in various emergencies. Based on this, a novel MR damper with displacement self-sensing and energy harvesting capability is proposed to solve the problems such as large structural size, high system cost, and vibration energy dissipation. Firstly, the structures of the MR damping, displacement self-sensing, and vibration energy harvesting are designed and integrated into the proposed MR damper. Then, the distribution of the magnetic flux density, displacement self-sensing voltage, and energy harvesting efficiency with a single induction coil and double induction coil is obtained using the finite element method. The experimental test system is set up and the performance of MR damping, displacement self-sensing voltage, and energy harvesting efficiency is experimentally tested. The experimental results show that the damping force reaches 513 N at the applied current of 0.25 A. At the same time, the amplitude of self-sensing voltage increases linearly with the increase of the amplitude of sinusoidal displacement excitation, and the displacement sensitivity comes up to 54.37 mV/mm. Moreover, the self-sensing voltage of the vibration energy harvesting component with a double induction coil is 2.512 V, and the energy harvesting efficiency is about twice than that with a single induction coil. It is found that the proposed MR damper, with a relatively compact structure and lower cost compared with traditional MR damper, not only promisingly achieves excellent dynamic damping performance but also simultaneously possesses displacement self-sensing ability and energy harvesting capability.

Effective Reduction of Cyclic Stresses in Coated Samples

Two condensed electron-beam copper coatings, one consisting of copper and the other of Hf/Ag/Ni/Cr microlayers, were deposited onto a titanium alloy (Ti−6Al−4V) substrate to study the energy dissipation and fatigue resistance in the uncoated and coated samples under nonbreaking and breaking cyclic stresses. The microlayer coating is peculiar in that a material with a higher elastic modulus is used in each subsequent layer (from the substrate to the outer layer) and the coating layers and submicron twins in the binder sublayer have a columnar microstructure peculiar to electron-beam evaporation and vacuum condensation. Having layered macro- and microstructure, the coating absorbs the energy of vibrations through both internal friction (between the coating layers and between the coating and substrate) and dissipation of vibration energy on numerous defects in the columnar structure (intercolumnar porosity). Resonant first- and secondmode vibrations were excited in cantilevered samples to determine how the vibration decrement depended on their maximum stresses and the breaking fatigue stresses on the number of load cycles. In addition, vibration transmission coefficients for cyclic stresses and vibration energy were experimentally defined and justified for use. One coefficient is equal to the ratio of difference in stresses between the uncoated and coated samples to stresses in the uncoated sample, relative machine power being the same in various tests. The other coefficient is equal to the ratio of difference in energy between the uncoated and coated samples to the energy of vibrations induced in the uncoated sample, relative machine power being the same in various tests. The Hf/Ag/Ni/Cr coating is shown to provide greater energy dissipation but lower fatigue properties than the Cu coating and substrate. The vibration transmission coefficients are more sensitive to energy dissipation than the vibration decrement is.

Quantifying moisture damage in asphalt concrete using axisymmetric flexural vibration technique

ABSTRACT The Tensile Strength Ratio (TSR) test is commonly used to quantify the moisture susceptibility of asphalt mixtures. This test method is based on the indirect tensile strength, which is not a fundamental property and hence cannot be used in the asphalt mixture design process. Therefore, alternative test methods that use a fundamental property to quantify moisture sensitivity of asphalt mixtures are needed. This study investigates if the linear impact resonance shift and frequency spectrum bandwidth changes measured using Axisymmetric Flexural Vibration (AFV) technique can be used to quantify moisture damage. This test enables calculation of the dynamic elastic modulus of the disk, based on measured resonance frequency as well as quantification of vibration energy dissipation in the specimens based on the change in bandwidth of frequency spectrum. AFV test is used to quantify moisture damage susceptibility of asphalt mixture specimens with different moisture conditioning levels and different mixture designs. The results of the AFV test are compared with the TSR test. Also, the sensitivity of the AFV test to quantify the effect of thixotropic aging due to storage and temperature are discussed. The results show that the AFV technique can successfully quantify moisture damage and the effect of aging and temperature change.

VIBRATION LEVEL EVALUATION OF ENGINES FUELED WITH BRAZILIAN COMMERCIAL DIESEL AND BIODIESEL

This paper is aimed to analyze vibrations from engines fueled with two different fuels, Brazilian commercial diesel (B8) and Biodiesel (B100). Consumption, level of particulate matter emissions and engine temperature were also analyzed. The experiments were performed considering noninvasive tests in a diesel engine, taking into account three different speeds: 800 rpm, 1800 rpm and 3600 rpm. Results showed that the engine energetic loss from vibration signals collected allowed a quantitative assessment of how each fuel influenced the engine vibration level. In the three analyzed speeds, B8 diesel fuel showed be more energetic when compared to B100 biodiesel fuel. Although the consumption using B100 biodiesel fuel presented higher values than B8, the level of particulate matter emissions was lower than commercial diesel B8. It was also noted that the vibration increased in both cases when the engine speed increased. B8 diesel presented a total vibration varying according to speeds range, from 4.5% to 21% higher than B100 biodiesel. Therefore, the dissipated vibration energy using B8 diesel was higher (10% to 45%) than B100 biodiesel. It is concluded that combustion is one of the item that generates higher level of vibration in diesel engines and it depends on the kind of fuel used.

Multimode cable vibration control using a viscous‐shear damper: Case studies on the Sutong Bridge

This study investigates multimode damping effects of a long cable attached with a viscous-shear damper (VSD). A typical VSD comprises a casing box containing viscous medium and shearing plates with parts submerged in the medium. It dissipates vibration energy through shear deformation of the viscous medium. The VSD is low-cost and invulnerable to leakage or increasing joint play and hence requires low maintenance effort. For studying its damping effects on long cables, three VSDs were designed respectively for three long cables of the Sutong Bridge, a cable-stayed bridge with a main span of 1,088 m, and then tested in laboratory under forced sinusoidal displacements with various frequencies and amplitudes. Their dynamic behaviors were found to be accurately modeled using a viscous damper with intrinsic stiffness, while the viscous and stiffness coefficients depend on frequency and amplitude. The VSDs were subsequently attached to the cables respectively, and modal damping ratios of in-plane modes of each cable without dampers and with the VSD were measured by free-decay testing. The measurements obtained for most in-plane modes with frequency less than 3 Hz show that the VSD provides satisfactory multimode damping effects with efficiency factors between 30% and 50% as compared to an ideal viscous damper and the damping decreases slightly for higher modes. The measurements are also found consistent with the results of complex modal analysis of a shallow cable with a Kelvin–Voigt damper considering frequency- and amplitude-dependent damper properties. Particularly, analytical prediction using the damper properties tested under small deformation amplitude provides the lower bound of the damping effect.

Research Review of a Vehicle Energy-Regenerative Suspension System

Vehicles are developing in the direction of energy-saving and electrification. suspension has been widely developed in the field of vehicles as a key component. Traditional hydraulic energy-supply suspensions dissipate vibration energy as waste heat to suppress vibration. This part of the energy is mainly generated by the vehicle engine. In order to effectively utilize the energy of this part, the energy-regenerative suspension with energy recovery converts the vibrational energy into electrical energy as the vehicle’s energy supply equipment. This article reviews the hydraulically powered suspension of vehicles with energy recovery. The importance of such suspension in vehicle energy recovery is analyzed. The main categories of energy-regenerative suspension are illustrated from different energy recovery methods, and the research status of hydraulic energy-regenerative suspension is comprehensively analyzed. Important factors that affect the shock-absorbing and regenerative characteristics of the suspension system are studied. In addition, some unresolved challenges are also proposed, which provides a reference value for the development of energy-regenerative suspension systems for hybrid new energy vehicles

Viscoelasticity of Rubber Springs Affects Vibration Characteristics of a Flip-Flow Screen With the High G Value

With the high G value of vibration, outstanding sieving behaviors of a flip-flow screen are more likely to appear, but structural damages are aggravated under the high amplitude vibration. Considering rubber springs role on the vibration energy dissipation, viscoelasticity of rubber springs (i.e., shear springs and vibration isolation springs), is noticed to deal with the above contradiction. However, when rubber springs experience large amplitude vibration, viscoelastic responses influence more on the amount of damping than in the linear (i.e., small amplitude) vibration regime, as the frequency dependence of rubber springs is noteworthy. For this purpose, the Generalized Maxwell model is used to depict the frequency dependence of rubber springs and the practical damping is converted to a series damping parameters of the system, numerical models of the flip-flow screen under startup and shutdown modes and steady working conditions are proposed and verified firstly. Secondly, in order to explore kinetics responses of the elastic screen panel under different rubber springs damping coefficients, nonlinear finite element model of which is established. Finally, effects of rubber springs nonlinear damping on screen frames vibrations and screen panels nonlinear responses are studied. Results indicate that hysteretic damping of rubber springs can effectively solve the conflict between vibration strength and structural reliability of the flip-flow screen, since the low sensitivities of maximum stresses and the high sensitivities of accelerations to rubber springs damping are found.

Magneto-liquid damping method and analysis of generated dissipative characteristics

The paper presents the problem of damping technological equipment oscillations by electrical systems. A method of reducing the emerging vibrations using dampers with a magnetic fluid is proposed. The variants of the optimal location of the permanent magnets and the interaction of their fields for the effective design of the magneto-liquid damper are considered. The optimal scheme is obtained – “for repulsion”. The analysis of the known statistical data is carried out, and the correlation dependence of the dynamic viscosity on the magnetic field parameters depending on the gap between the permanent magnets is obtained. The values of vibration energy dissipation for the proposed magnetic- liquid damping method are obtained. The universality and adaptability of this method of damping vibrations in the process of reducing the vibrations of the technological equipment have been proved.

Efficiency of vibrational energy dissipation by tuned rolling-cylinder dampers

The damping efficiency of a tuned rolling-cylinder damper in a horizontally vibrating system under sinusoidal excitation was investigated experimentally and analytically. The damper is an auxiliary system and consists of some rotary bodies placed on a circular arc surface attached to the primary system. The friction force between rotary bodies is a source of energy dissipation of the auxiliary system. In an experimental approach, the effects of the size of rotary bodies, the number of rotary bodies with different radii used in combination and the amplitude of external excitation on the damping performance were investigated. In an analytical approach, an analytical model based on the discrete element method was constructed. The validity of the analytical model was confirmed by comparing experimental and analytical results. In addition, the effect of the radius of the circular arc surface on the damping performance was examined analytically.

Development and evaluation of a versatile semi-active suspension system for high-speed railway vehicles

Abstract With the increase in speed of high-speed trains, their vibration will become fiercer and fiercer, especially when the lateral resonance of the car body occurs. This paper develops a versatile semi-active suspension system with variable stiffness (VS) magnetorheological elastomer (MRE) isolators and variable damping (VD) magnetorheological (MR) dampers for high-speed trains, aiming to improve ride comfort by avoiding car body resonance and dissipating vibration energy. As the first step, a multifunction VSVD semi-active suspension system for high-speed railway vehicles was designed and prototyped, including four VS-MRE isolators and two VD-MR dampers. After that, a scaled train model, composing of a car body and a secondary lateral suspension system was designed and built to evaluate the performance of the new VSVD suspension system; a control strategy based on short-time Fourier transform (STFT) and sky-hook was proposed to control the new suspension system. Two different excitations, harmonic excitation and random excitation, were applied to evaluate the train’s VSVD suspension. As a comparison, four alternative suspension systems, including passive-off suspension, passive-on suspension, pure VS suspension, and pure VD suspension were also evaluated. The evaluation results verified that the VSVD suspension of the train can avoid lateral resonance of car body and dissipate the vibration energy efficiently. The comparison verified that the VSVD suspension system outperforms the passive-off suspension, passive-on suspension, pure VS suspension, and pure VD suspension.

Energy Harvesting from Vehicle Suspension System by Piezoelectric Harvester

In this paper, a new type of piezoelectric harvester for vehicle suspension systems is designed and presented that addresses the current problems of low energy density, vibration energy dissipation, and reduced energy harvesting efficiency in current technologies. A new dual-mass, two degrees of freedom (2-DOF), suspension dynamic model for the harvester was developed for the inertial mass and the force of the energy conversion component by combining with the piezoelectric power generation model, the rotor dynamics model, and the traditional 2-DOF suspension model. The influence of factors such as vehicle speed, the parameters of the harvester, and road classification on the root mean square (RMS) of the generated electric power is discussed. The results show that the RMS increases with the increase of the speed of the vehicle, the thickness and length of piezoelectric patches and magnetic slabs, and the residual flux density of magnets and road roughness coefficient and with the decrease of the width of piezoelectric patches and magnetic slabs and the space between the stator ring and the rotator ring. In the present research, a power of up to 332.4 W was harvested. The proposed model provides a powerful reference for future studies of energy harvesting from vehicle suspension systems.