Particle Impact Damper Research Articles

Research on a New Particle Impact Damper

The conventional impact damper cannot completely exhaust vibration energy through momentum exchange and friction. To overcome these shortcomings, this paper proposes a new particle impact damper (PID) which for the first time introduces the fine particle plastic deformation as an irreversible energy sink. Then, the experiments of the cantilevered beam with the CID and that with the PID are respectively carried out to investigate the behaviour of PID. The experimental results indicate that the PID has a better performance in vibration damping than the CID. And the PID works well in control of the vibration with frequency lower than 50 Hz, which is absent to the non-obstructive particle damper. Thus, the PID has a bright and significant application future because most of the mechanical vibration falls in the range of low frequency.

Investigations of Particle Impact Damper with Elastic Support

Compared with traditional impact damping devices, particle impact damper under elastic support, a new impact damper with double damping structure, has better damping performance. For the purpose of further studying its damping effects on cantilever beam, this paper comes up with both the dynamic model and the movement differential equation of the particle impact damper system with elastic support, and stimulates the damping effects of cantilever beam under the influence of this device. Simultaneously, based on experiments on the damping effects of the particle impact damper with elastic support under five different stiffness conditions, it is concluded that: results from the theoretical calculation basically agree with those from experiments, which verifies the reliability of the calculation model of the particle impact damper with elastic support built by this paper.

Analysis for Material of Particle of Particle Impact Damper on Damping Performance of Fixed Fixed Beam

Analysis for Material of Particle of Particle Impact Damper on Damping Performance of Fixed Fixed Beam

Particle impact dampers: Past, present, and future

Particle damping, an effective passive vibration control technology, is developing dramatically at the present stage, especially in the aerospace and machinery fields. The aim of this paper is to provide an overview of particle damping technology, beginning with its basic concept, developmental history, and research status all over the world. Furthermore, various interpretations of the underlying damping mechanism are introduced and discussed in detail. The theoretical analysis and numerical simulation, together with their pros and cons are systematically expounded, in which a discrete element method of simulating a multi-degree-of-freedom structure with a particle damper system is illustrated. Moreover, on the basis of previous studies, a simplified method to analyze the complicated nonlinear particle damping is proposed, in which all particles are modeled as a single mass, thereby simplifying its use by practicing engineers. In order to broaden the applicability of particle dampers, it is necessary to implement the coupled algorithm of finite element method and discrete element method. In addition, the characteristics of experimental studies on particle damping are also summarized. Finally, the application of particle damping technology in the aerospace field, machinery field, lifeline engineering, and civil engineering is reviewed at length. As a new trend in structural vibration control, the application of particle damping in civil engineering is just at the beginning. The advantages and potential applications are demonstrated, whereas the difficulties and deficiencies in the present studies are also discussed. The paper concludes by suggesting future developments involving semi-active approaches that can enhance the effectiveness of particle dampers when used in conjunction with structures subjected to nonstationary excitation, such as earthquakes and similar nonstationary random excitations.

A spring-supported fine particle impact damper to reduce harmonic vibration of cantilever beam

Spring-supported fine particle impact damper which integrates the effects of elastic deformation and the plastic deformation performs excellently on the attenuation of vibration in cantilever beam....

Effectiveness of particle and mass impact damping on tool vibration during hard turning process

In the machine tools, tool vibration is an undesirable phenomenon which affects tool life, quality of machined surface and produces irritating noise. This tool vibration is due to the interaction between metal cutting process and forces acting on the machine tool. In this investigation, an attempt was made to reduce tool vibration during turning of hardened steel using particle and mass impact dampers. A mass impact damper used in this investigation consists of a concentrated mass made of copper mounted on the bottom of the tool holder and particle damper consists of copper particles of 3.5 mm diameter positioned along the axis of the tool holder. Particle size and its location were designed using computational analysis and impact hammer–based modal testing was performed for both dampers. When these dampers were mounted on the tool holder, particles will collide with each other and subdue the vibration produced in the tool holder. Cutting experiments were conducted to study the influence of mass and particle damping on tool vibration and cutting performance during turning of hardened AISI4340 steel using hard metal insert with sculptured rake face. From the results, it was observed that the use of mass impact and particle dampers enhances the rigidity of the tool holder which, in turn, reduces tool vibration and improves the cutting performance. Among the two dampers, it was found that the presence of mass impact damping provides superior cutting performance when compared to particle damping.

A combined approach for modeling particle behavior in granular impact damper using discrete element method and cellular automata

A particle impact damper is a vibration absorber type that consists of a container attached to a primary vibrating structure. It also contains many particles that are constrained to move inside the container, whereby the damping effect can be obtained by collision between particles and the container. The discrete element method (DEM) has been developed for modeling granular systems, where the kinematics of each particle are calculated numerically using the equations of motion. However, the computational time is significant since the algorithm checks for particle contacts for all possible particle combinations. The use of a cellular automata (CA) modeling technique may provide increased computational efficiency due to the local updating of variables, and the discrete treatment of time and space. In this study, we propose a new approach combining DEM with CA for modeling a granular damper under a forced excitation. We use DEM to describe the particle motion according to the equations of motion, while CA is introduced for the particle contact checks in discrete space. We also investigate the effect of simplification in the contact force model, which allows the unit time step of numerical integration to become larger than that used in the strict model. It is shown that the suggested particle contact scanning method and the force approximation model contribute to the reduction of the computational time, and neither degenerates the calculation accuracy nor causes the numerical instability.

The use of carbide and particle-damped bars to increase tool overhang in the internal turning of hardened steel

Vibrations are very prejudicial to machining as they directly affect the dimensional accuracy and surface roughness of the machined part. Excessive vibration must be avoided or at least reduced. This can be achieved in several ways, including the use of dampers and more rigid material for tool holders. Tool vibration is stimulated in internal turning by the cantilever shape of the tool and the large tool overhang used, impairing the quality of the turned part. This is a serious problem in the turning of hardened steel because internal turning is usually the last operation carried out on the surface, making tight tolerances and low surface roughness values necessary. Excessive vibrations would harm the surface finish and could lead to tool breakage because of the low toughness of the tool materials used for this kind of application. The main objective of this work was therefore to identify alternative approaches for finishing internal turning of long holes in hardened steel parts. Different tool holder materials (steel and cemented carbide) and a particle impact damped steel tool holder were tested to determine the longest overhang that could be achieved in each configuration. The results showed that carbide bars reduced vibrations and allowed longer overhangs to be used. Particle impact dampers may be a simple alternative to the more expensive carbide bars.

Railway vibration and noise reduction using particle impact dampers

Rolling noise is becoming a increasing concern for residential areas near railways. Rail vibration caused by moving loads of a train and corrugations generates noise. This study presented a particle impact dampers and its application to reduction of the rolling noise. The particle impact dampers to efficiently reduce the vibration were designed and verified using simplified models of a railway. To verify the particle impact damper performance, the vibration of a simplified railway attached with particle impact dampers was measured. The effects of different clearances and mass ratio of the damper to the railway was investigated. The numerical predictions of finite element model of impacting dampers were proposed and verified to the measured results to find the vibration reduction mechanism.

Removable damping treatments for use in sheet metal fabrication

Many industrial fabrication processes on metallic structures generate a great deal of work place noise. For example, riveting and chiseling on light-weight, stiff aerospace structures such as fusalage components and flight surfaces subject the workpiece to repeated impacts and consequent noise generation. Many such structures may be lightly damped. Many damping treatments are targeted toward permanent installation on a structure, but if the treatments are considered to be removable, one has design freedoms including placement on a structure, as well as mass and damping means, that might not otherwise exist if the treatment had to remain in place. A shot-mass or particle-impact damper configured in an elastic, cellular array is shown to provide high loss factors and mass loading, which, along with ease of placement and removal, may provide significant reduction in component vibration during fabrication and consequent reduction in noise in the work place. The concept applied to an example aircraft panel when subjected to riveting operations yields more than 10 dB of noise reduction.

A REVIEW ON VIBRATION MITIGATION OF BORING BAR USING PASSIVE DAMPING TECHNIQUES

Work piece and tool vibration control has been a subject of primary importance in manufacturing industry. High slenderness ratio is a reason for boring bar to be subjected to high amount of vibrations that accelerate the tool wear affecting the tool life, higher noise level and increased deviations. This review focuses on various damping techniques such as passive damping systems using particle impact damping and Magneto-Rheological (MR) fluid for vibration attenuation purpose. This also introduces the mechanics of boring operation that affects the tool wear, surface roughness, noise and hence affects the productivity. This review compares the results of boring bar using passive damping and the conventional tool on the basis of modal analysis of vibrating structure, and the test results. This paper explains the vibration behavior of a conventional boring bar and a boring bar using passive techniques for vibration reduction.

Investigation into effect of particle impact damping (PID) on surface topography in boring operation

This paper presents a novel method, based on the particle impact damping (PID), for the attenuation of regenerative vibration in boring operation. A specially designed boring bar having a cavity near machining-end for partial filling of spherical particles has been developed. Characteristics of boring bar with and without PID have been found from impact and shaker tests. After identifying appropriate particle size and filling volume, experiments are conducted to evaluate the performance in actual boring operations. Additional boring experiments are also conducted to confirm the performance by changing particle size and filling volumes. The collision of the particles in PID is found to attenuate regenerative vibration by the energy dissipation and thus effectively enhances stability of the boring operation. Analysis of effect of PID on surface topography in terms of chatter marks, surface roughness, and roundness of bored holes shows that the proposed method results in improvement of bore quality when compared with a boring bar without PID. It is also established that radial vibration of the boring bar has a significant influence on the surface topography obtained in boring operation.

SURFACE QUALITY ENRICHMENT USING FINE PARTICLE IMPACT DAMPER IN BORING OPERATIONS

Boring operations are challenging owing to limited process performance due to inherent tool overhang a nd resulting vibrations. The tool vibrations can be suppressed with insertion of suitable damping methodology. The fine particle im pact damping offers a better damping method. Due to its conceptual simplicity, p otential effectiveness over a wide frequency range, temperature and degradation insensitivity and cost-effectiveness, particle damp ing is an attractive passive damping. The fine particles embedded within small hole in a vibrating structure to dissipate the exciting energy thereby damping the vibrations. The present work, investigates the improvement of surface quality of boring operation using fine particle impact damper. Substantial impr ovement of surface quality of the internally machined surfaces has been noticed i n the experiments.

English

Everything in the universe that has mass possesses stiffness and intrinsic damping. Owing to the stiffness property, mass will vibrate when excited and its intrinsic damping property will act to stop the vibration. The particle impact damper (PID) is a very interesting damper that affects impact and friction effects of particles by means of energy dissipation. PID is a means for achieving high structural damping by using a particle-filled enclosure attached to a structure. The particles absorb the kinetic energy of the structure and convert it into heat through inelastic collisions between the particles themselves and between the particles and the walls of the enclosure. In this work, PID is measured for a cantilever mild steel beam with an enclosure attached to its free end; copper particles are used in this study. The PID is found to be highly nonlinear. The most useful observation is that for a very small weight penalty (about 7% to 8 %), the maximum damped amplitude of vibration at resonance with a PID, is about 9 to 10 times smaller than that without a PID. It is for more than that of with only intrinsic material damping of a majority of structural metals. A satisfactory comparison of damping with and without particles through experimentation is observed. The effect of the size of the particles on the damping performance of the beam and the effective packing ratio can be identified. It is also shown that as the packing ratio changes, the contributions of the phenomena of impact and friction towards damping also change. It is encouraging that despite its deceptive simplicity, the model captures the essential physics of PID.

Prediction of the dynamic response of a plate treated by particle impact damper

In this paper, an experimental characterisation of a particle impact damper (PID) under periodic excitation is investigated. The developed method allows the measurement of damping properties of PID without the supplementary use of a primary structure. The passive damping of PID varies with the excitation frequency and its design parameters. The nonlinear damping of PID is then interpreted as an equivalent viscous damping to be introduced in a finite element model of a structure to predict its dynamic response. The results of numerical simulations are in good agreement with those of experiment and show the relevance of the developed method to predict the dynamic behaviour of a structure treated by PID’s.

Modeling the fine particle impact damper

The fine particle impact dampers (FPIDs) using plastic deformation of fine particles as irreversible energy sink can exhaust much more vibration energy than single mass impact dampers (SMIDs) and thus can work well in low frequency domain. A numerical model is set up in this paper to capture the complex physics involved in the FPID. Experimental results on a cantilever beam with FPID showed good agreement with the model predictions. We show that in all cases the damping performances of the FPID are much better than that of the SMID, and fine particles enrolled in the FPID play a key role in vibration energy dissipation. The damper clearance and the mass ratio are two important parameters for the damping ability of the FPID, for which an optimal combination of them exists targeting the largest damping ability.

Energy dissipation in collision of two balls covered by fine particles

A new fine particle impact damper (FPID) is composed of a spherical impactor and a small quantity of fine particles as damping agent. The model of energy dissipation in the collision between two balls covered by fine particles is necessary to investigate the mechanism and performance of FPID. In this study, a simplified model verified by FEA simulations is proposed to estimate the energy dissipation in collision between two balls covered by fine particles. In addition, the energy dissipation in the collision between two balls covered by fine particles is compared with that in the impact between two balls without fine particles, by means of theoretical predictions. FEA simulations are also carried out to discuss the effects of diameter ratio of particle to ball, particle material and particle amount on the energetic expression of the elastic–plastic loading (EPL) index (EPL E). The results from the FEA simulations agree well with the estimations from the model proposed in this paper. It is concluded that the energy dissipation in the collision between two balls covered by fine particles can be predicted by classical collision models of two particles through the substitution of several parameters from balls; the plastic deformation of fine particles affixed on balls can exhaust much more energy than that of the two balls without particles, which is the reason for the good performance of FPID; the diameter ratio of particle to ball and the material of particles do not have significant effects on the EPL E when the ratio is limited to the range of [1/200 – 1/10]. A correlation of the EPL E and dimensionless initial relative velocity is also found for the collisions between two balls, which is independent not only of the particle size and material properties but also of the particles presence.

Particle Impact Damping in Two Dimensions

Particle impact damping (PID) is a technique of achieving high structural damping with small metallic particles embedded within a cavity that is attached to vibrating structure. This is a highly non-linear damping mechanism in which energy dissipation is primarily related to friction and impact phenomena. In this work a simple yet detailed analytical model is presented to study PID in two dimensions under transient vibrations. Normal as well as oblique impacts are considered. The effect of cavity size and acceleration amplitude on PID is studied and the results are supported by experiments. Fairly good agreement is found between the theory and the experiment.

An experimental study of a multi-particle impact damper

In this article, an experimental study of a vertical particle impact damper under free excitation is investigated. Specific impact damping is determined for a primary structure (clamped-free beam) with an enclosure attached to its free end and containing a lead particle. The influence of some system parameters such as clearance and intensity of excitation are investigated. An analytical model based on the concept of an equivalent system with impacting mass is presented and used to compute the specific impact damping. Driven by the experimental observation, it has been shown that a high value of specific damping capacity was reached with a particle impact damper. The obtained results prove the efficiency of this process for achieving high structural damping.

Dynamics and Performance of a Harmonically Excited Vertical Impact Damper

Particle impact dampers (PIDs) have been shown to be effective in vibration damping. However, our understanding of such dampers is still limited, based on the theoretical models existing today. Predicting the performance of the PID is an important problem, which needs to be investigated more thoroughly. This research seeks to understand the dynamics of a PID as well as those parameters which govern its behavior. The system investigated is a particle impact damper with a ceiling, under the influence of gravity. The base is harmonically excited in the vertical direction. A two-dimensional discrete map is obtained, wherein the variables at one impact uniquely dictate the variables at the next impact. This map is solved using a numerical continuation procedure. Periodic impact motions and “irregular” motions are observed. The effects of various parameters such as the gap clearance, coefficient of restitution, and the base acceleration are analyzed. The dependence of the effective damping loss factor on these parameters is also studied. The loss factor results indicate peak damping for certain combinations of parameters. These combinations of parameters correspond to a region in parameter space where two-impacts-per-cycle motions are observed over a wide range of nondimensional base accelerations. The value of the nondimensional acceleration at which the onset of two-impacts-per-cycle solutions occurs depends on the nondimensional gap clearance and the coefficient of restitution. The range of nondimensional gap clearances over which two-impacts-per-cycle solutions are observed increases as the coefficient of restitution increases. In the regime of two-impacts-per-cycle solutions, the value of nondimensional base acceleration corresponding to onset of these solutions initially decreases and then increases with increasing nondimensional gap clearance. As the two-impacts-per-cycle solutions are associated with high loss factors that are relatively insensitive to changing conditions, they are of great interest to the designer.