Particle Damping Research Articles

Experimental and analytical studies of the dynamic behavior of particle dampers prepared with waste cement‐based materials

AbstractThe particle damper made of steel balls has a great capability of vibration attenuation. However, its noise causes serious problems in the comfortability of structures. In this study, waste concrete aggregates and powders are utilized as particles in particle dampers, aiming to reduce the generated noise and achieve comparable performance as well as better environmental and ecological benefits. The parameters, including damper type, particle materials, earthquake waves, particle number, and tunning frequency on the damping performance, are investigated through free vibration test and shaking table tests. The results show that the damping ratio and seismic performance of this novel damper are comparable to those of the steel particle dampers. Moreover, simulation was conducted based on theoretical analysis. Finally, the generated sound is tested and proved less than the commonly adopted steel ball damper. This study can encourage the application of particle dampers by reducing noise and cost, besides, promotes the environmental benefits by extending the usage of recycled building materials.

Experimental Investigation on the Vibration Attenuation of Tensegrity Prisms Integrated with Particle Dampers

Experimental Investigation on the Vibration Attenuation of Tensegrity Prisms Integrated with Particle Dampers

Energy dissipation in horizontally driven particle dampers of low acceleration intensities

The energy dissipation in sinusoidally driven particle dampers is highly dependent on the motion mode of the particle bed. Especially, for applications of low acceleration intensity, i.e., acceleration amplitude below gravitational acceleration, only small energy dissipation rates are obtained so far, due to sticking of particles. Here, a new and more efficient design of particle dampers is introduced for such applications, whereby the focus is on horizontal vibrations. The proposed design makes use of the rolling property of spheres inside particle containers with flat bases. First, a cuboid container shape is studied. Two different motion modes are observed experimentally within this container shape. For low driving amplitudes, the particle bed is showing a scattered behavior resulting in a low damping efficiency. For high driving amplitudes instead, the rolling collect-and-collide state is observed resulting in much higher efficiency. Analytical descriptions for the energy dissipation are derived for both motion modes, being in good agreement with experimental measurements. It is obtained that the optimal working point of such dampers, i.e., the optimal stroke, is only depending on the filling ratio of the damper. Additionally, the optimal working point separates both motion modes. For lower strokes as the optimal one, the scattered state is observed, while for higher strokes the rolling collect-and-collide mode is seen. Sensitivity analyses are performed using the experimental setup and discrete element simulations. It is obtained that especially a low friction coefficient and a high particle radius are beneficial. On the other hand, a small tilt around the container’s longitudinal or pitch axis might significantly decrease the efficiency of the damper. Besides the cuboid container, the effect of a cylindrical container heading against gravity is analyzed. While the particle bed motion modes are only little influenced, the efficiency of the damper becomes independent of the excitation direction in the horizontal plane. Thus, such dampers could be applied to a large field of applications in mechanical and civil engineering.

Design of Particle Dampers for Laser Powder Bed Fusion

Additively manufactured particle dampers can significantly improve component damping. However, if designed incorrectly, the damping can be worsened. For the design of additively manufactured particle dampers, there are not yet sufficient design rules and models to describe the effect due to numerous design parameters. The research question answered in this paper describes how the effect of particle damping can be characterised as a function of excitation force and excitation frequency for different cavity sizes. To characterise the effect of particle damping, a 33 full factorial test plan is constructed, and the damping is determined experimentally. It is shown that the damping can be reliably evaluated with the circle-fit method. The effect of particle damping is investigated for beams made of AlSi10Mg, 1.2709 and Ti6Al4V. As a result, a positive effect of the particle damping in a frequency range from 500 to 30,000 Hz and partly up to the 9th bending mode can be proven. It is shown that, for the first bending mode, there is an optimum at approx. 2000 Hz. For the optimum, the increase of the damping for the tool steel 1.2709 to 28 and for the aluminium alloy AlSi10Mg to 18 can be proven.

Study on Damping Behavior of Electromagnetic Particle Dampers with a Ferromagnetic End Cover in Weightless Environments

Study on Damping Behavior of Electromagnetic Particle Dampers with a Ferromagnetic End Cover in Weightless Environments

Experimental investigation of dynamic vibration absorption to design an improved particle damper

We introduce a tuned particle damper (TPD) to improve the damping performance of the traditional particle damper by adding a dynamic vibration absorption structure. To better design a TPD as a dynamic vibration absorber (DVA), we changed the dynamics of a DVA system based on a primary cantilever system by introducing stainless steel balls and a carbon steel mass block. Using a series of sine-sweep tests on the primary cantilever system attached with a spring-mass system, we obtained frequency response function (FRF) curves under different conditions. Our experimental results show that the dynamic behavior of the primary cantilever system was more prominent on the resonance peak closer to the mass control area, whereas the dynamic behavior of the additional spring-mass system is more prominent on the resonance peak closer to the stiffness control area. Based on these results, we analyzed the abnormal but desirable dynamic characteristics of TPD presented in the discrete mass experiment, and the results indicates preliminary success with our design of a TPD.

Application of Particle Dampers on a Scaled Wind Turbine Generator to Improve Low-Frequency Vibro-Acoustic Behavior

The purpose of this paper is to introduce a honeycomb damping plate (HCDP) concept based on the particle damping technique to reduce the low-frequency vibration response of wind turbine generators. The HCDP cells contain granular materials and are mounted at different positions on the generator to reduce the transmission of vibrations from stator ring to stator arm. To investigate the efficiency of the HCDP concept in the laboratory, a small-scale replica inspired by the original wind turbine generator is used as reference geometry. The efficiency of the vibration attenuation by using the HCDP concept is experimentally investigated with the help of a laser scanning vibrometer device. In this contribution, the influence of four different granular materials on the vibration attenuation is experimentally investigated. Furthermore, the influence of HCDP positioning on the transmission path damping is analyzed. Apart from this, the effect of single-unit (SU) and multi-unit (MU) HCDP on the frequency response of the generator is also studied. The experimental approach in this paper shows good damping properties of the HCDP concept for reducing the vibration amplitude.

Investigation on Isolation Improvement Performance of Floating Raft System with Particle Dampers

Investigation on Isolation Improvement Performance of Floating Raft System with Particle Dampers

Study on the Vibration Reduction of Internal Combustion EMU Powerpack Frame under Multiple Loading Conditions Based on Particle Damping

Study on the Vibration Reduction of Internal Combustion EMU Powerpack Frame under Multiple Loading Conditions Based on Particle Damping

Effect of sphere configurated particle damper on tribological properties during boring of hardened steel

Tool vibration is the most unfavourable element in the boring operation, as it contributes to poor surface finish, excessive tool wear, and progressive cutting force. Tool vibration mainly occurs due to the overhanging length of the boring tool and to overcome this factor an appropriate mechanism has to be established which helps to increase the production and quality of the product in manufacturing sector. An impact particle damper with variable material spheres, sphere diameter, and sphere location in a boring tool is fabricated in this work. A 27 run experiments were conducted to find the effect of impact particle damping on tribological properties during boring process. The results shows that impact particle damper increases the rigidity of the tool holder which enhances the tribological properties. The sphere in the boring tool will collide with one another thereby suppressing the tool vibration efficiently.

Numerical and experimental analysis of additively manufactured particle dampers at low frequencies

Particle damping is an effective method for increasing structural damping and is utilized in many fields. Using laser powder bed fusion (LPBF) additive manufacturing (AM), a new integrated particle damper can be produced by deliberately leaving unfused powder inside the structure. This study focuses on experimentally and numerically investigating the damping mechanism and performance of additively manufactured particle dampers in the low-frequency range (< 100 Hz). A numerical simulation approach based on the discrete element method was developed to predict the damping performance of a particle damper. To reduce the computational cost, a multi-unit particle damper (MUPD) was introduced. A series of particle dampers of 316 L stainless steel with different numbers and sizes of unit cells were built using LPBF. The damping mechanism and performance of additively manufactured MUPDs (AM-MUPD) were studied, the results cross-verified via experiments and simulations, and the effects of unit cell size and number investigated.

A simplified modeling method for multi-particle damper: Validation and application in energy dissipation analysis

Particle dampers have received considerable attention in recent years as a novel damping technique. However, due to its high degree of nonlinearity, no mature damping model has been constructed. This article proposes an equivalent raft model that takes into account both the three-dimensional geometry and the material property. The model is validated by comparing the benchmark results with experimental observations and to simulations using the discrete element method. The equivalent raft model predicts the behavior of the structure–damper system in the presence of ground motion. Additionally, it can compute the time evolution of particles’ displacement and force in three different function modes. Moreover, the energy dissipation mechanism of particle damper is investigated using the suggested model to analyze the impact of load amplitude, load frequency, container size, particle mass, and particle material.

Comparative study of the damping performance of concentrated masses and particle dampers based on cantilever beams

This paper investigates the damping performance of the main structure with a concentrated mass and particle dampers at different particle filling rates and sinusoidal sweep amplitudes under the same mass ratio by means of a controlled experiment, with the concentrated mass and particle dampers attached to the free end of the cantilever beam. As the order increases, the effect becomes progressively weaker. For cantilevered beam structures, a reasonable design with only a small mass ratio of particle dampers can effectively suppress the vibration of the first order. For the second- and third-order bending vibration, particle dampers with high mass ratios show a better damping effect, and when the strength of the excitation reaches a certain value, the damping performance of the particle dampers is basically better than that of the concentrated mass under the same conditions. The reason for this is that particle damping not only dampens the vibration by tuning the mass but also dissipates the energy of the main structure by means of collisions, impacts, and friction between the particles or between the particles and the damper cavity.

Modeling and experimental analysis of particle damping phononic crystal plate

A phononic crystal with particle assembly dampers was constructed. A high-speed camera was used to record and observe the vibration phenomenon of the particle assembly under external excitation. By analyzing the vibrations of the particle assembly, a continuous system equivalent to the discrete particle assembly was proposed. The particle damping equivalent model was fitted to data using an artificial neural network. Two particle damping phononic crystal plates were designed. Based on the equivalent model, a particle damping phononic crystal model was established. The results of the simulations and experiments showed that the average damping effect of the particle damping structure was greater than 75%. Particle damping phononic crystals possess excellent low vibration transmission characteristics, narrow bandgap characteristics at low frequencies, and high damping characteristics.

Substructure Shake Table Testing of Frame Structure–Damper System Using Model-Based Integration Algorithms and Finite Element Method: Numerical Study

Substructure shake table testing (SSTT) is an advanced experimental technique that is suitable for investigating the vibration control of secondary structure-type dampers such as tuned mass dampers (TMDs). The primary structure and damper are considered as analytical and experimental substructures, respectively. The analytical substructures of existing SSTTs have mostly been simplified as SDOF structures or shear-type structures, which is not realistic. A common trend is to simulate the analytical substructure via the finite element (FE) method. In this study, the control effects of four dampers, i.e., TMD, tuned liquid damper (TLD), particle damper (PD) and particle-tuned mass damper (PTMD), on a frame were examined by conducting virtual SSTTs. The frame was modeled through stiffness-based beam-column elements with fiber sections and was solved by a family of model-based integration algorithms. The influences of the auxiliary mass ratio, integration parameters, time step, and time delay on SSTT were investigated. The results indicate that the TLD had the best performance. In addition, SSTT using model-based integration algorithms can provide satisfactory results, even when the time step is relatively large. The effects of integration parameters and time delay are not significant.

Energy analysis of particle tuned mass damper systems with applications to MDOF structures under wind-induced excitation

In recent years, particle damper has been proved to be an effective vibration control strategy in various fields. In this study, an energy-evaluation model of particle tuned mass damper (PTMD) attached on a Multi Degree of Freedom (MDOF) structure (76-story high-rise building) under wind excitation is established based on an equivalent simplified method, and the simulation results are validated by a wind tunnel experiment. The energy related in the whole structural system, including the kinetic energy, elastic potential energy, energy dissipated by the structural damping and external input energy, has been analyzed in detail, and the energy transmission effect between the main structure and the attached PTMD has been investigated through the time history response of the input energy distribution. It is found that PTMD shows favorable energy dissipation performance, a large percentage of the input energy transfers from the main structure to PTMD in the first few seconds, and after that the particle-container wall collision consumes the main proportion of the input energy. Moreover, a series of systematic parametric analyses are conducted, including volume filling ratio, PTMD auxiliary mass ratio, particle damping coefficient and frequency ratio of PTMD. Furthermore, a full factorial study is conducted to investigate the interaction effect of different parameters. The results show that the combination of the parameters has a significant effect on the energy dissipation performance of PTMD, a parametric designing procedure has been given accordingly.

Design of a particle damper and experimental study on vibration damping of the pipeline

In this work, we designed a particle damper which can be conveniently clamped on to a pipeline without affecting the existing structure, showing a promising application in vibration reduction of real aircraft. Based on the designed particle damper, the impact of particle filling rate on the vibration reduction effect, the effect of EDEM simulation on the energy consumption of particles in the vibration process of the damper, and the result of actual vibration reduction test of particle damper installed on hydraulic pipeline were investigated. It is found that the vibration of the pipeline decreases first and then increases with the increase of particle filling rate. The particle filling rate corresponding to the maximum particle energy consumption rate is consistent with that of the minimum pipeline vibration acceleration during the test, that is, from 94.9% to 97.9%. The simulation results are in good agreement with the test results. Moreover, the vibration of the hydraulic pipeline and actual aircraft pipeline are both obviously suppressed after the installation of the particle damper. These results fully demonstrate the effectiveness and practicability of the aircraft pipeline particle damper.

Investigation of the toroidal flow damping in the edge plasma of J-TEXT tokamak with an electrode biasing

The toroidal flow damping has been investigated in the edge plasma of J-TEXT tokamaks with an electrode biasing (EB). The estimated viscosity of the toroidal flow after the bias turning off is about 67 times of the classical viscosity and four times of the neo-classical viscosity, which infers that the flow damping is anomalous in the transition phase. In the equilibrium phase, the torque densities driven by the EB, the momentum transport, and the neo-classical toroidal viscosity (NTV) under different bias conditions are calculated, which show that the NTV torques are comparable with the other terms. According to the angular momentum balance equation, the remnant damping torque densities and the effective damping coefficients have been obtained. Considering that the remnant damping is mainly contributed by the neutral particle damping, this investigation provides a method to estimate the neutral particle density (nH), which gives that the nH in the edge plasma of J-TEXT is in the range of 1–4 (×1017 m−3).

A rapid compression machine coupled with time-resolved molecular beam mass spectrometry for gas-phase kinetics studies.

Rapid compression machines (RCMs) are used to simulate a single stroke of an internal combustion engine. After a high-speed compression process, a high-pressure and low-to-intermediate temperature condition can be obtained, under which ignition processes are usually studied. With the help of different diagnostic methods, the detailed speciation information of the ignition process can be quantified. In this study, the molecular beam mass spectrometry (MBMS) diagnostic method was applied on an RCM to realize time-resolved concentration profile measurements. To realize the combination between RCM and MBMS, particle dampers were adopted to suppress the vibrations of the RCM, and a novel flexible interface was designed to maintain a high vacuum, which ensured the safe and effective operation of a high-repetition-rate time-of-flight mass spectrometer (HRR-TOF-MS). The detailed configuration of this diagnostic method is presented, and the data acquisition system and data analysis method are described. The arrangement was validated through the investigation of the well-studied decomposition of 1,3,5-trioxane at temperatures between 697 and 777K at 10 bars. The measured concentration profiles of 1,3,5-trioxane and formaldehyde were in good agreement with previous experimental and theoretical calculation results. The experimental results showed that the newly developed RCM coupled with the HRR-TOF-MS has advantages in time-resolved speciation measurements at low-to-intermediate temperatures and high pressures, and it can be applied in low-temperature combustion chemical kinetics studies.

Experimental study of particle dampers applied to wind turbine blades to reduce low-frequency sound emission

Sound emission from an onshore wind turbine is one of the significant hurdles to use wind energy to its full potential. The vibration caused by the generator is transmitted to the blades, which radiates the sound to the surrounding. The purpose of this experimental study is to present a passive vibration reduction concept, which is based on the high damping properties of granular materials. The efficiency of this concept will be investigated using a laser scanning vibrometer device. For the experimental purpose in the laboratory, small-scale replicas inspired by the original configurations are used as reference geometries for the wind turbine generator and the blades. Vibrations of the prototype, with and without granular material filling, will be determined and compared with each other. The influence of the amount of granular material inside the structure is also investigated. Apart from this, different types of granular filling are examined with respect to their efficiency in reducing the amplitude of vibration of the structure while being as light as possible in order to design a lightweight solution, which increases the overall mass of the wind turbine marginally.