When the actual installation center distance between a pair of spur gears is greater than the theoretical center distance,backlash increases,leading to increased vibration and noise.The structural parameters of an int...When the actual installation center distance between a pair of spur gears is greater than the theoretical center distance,backlash increases,leading to increased vibration and noise.The structural parameters of an integral squeeze film damper(ISFD)were designed with the stiffness of rigid support as reference to investigate the effect of an ISFD on the dynamic characteristics of a spur gear transmission system with center-distance installation error.A spur gear test bench with center distance-error was built to investigate the vibration and noise reduction characteristics of ISFD.The experimental results indicate that,compared with a rigid support,the ISFD can reduce vibration by approximately 40%and noise by approximately 5 d B.ISFD can effectively absorb the impact energy caused by an increase of in backlash,which is conducive to the stable operation of the spur gear transmission system.展开更多
We theoretically investigate the application of the fringe-locking method(FLM) in the dual-species quantum test of the weak equivalence principle(WEP).With the FLM,the measurement is performed invariably at the mi...We theoretically investigate the application of the fringe-locking method(FLM) in the dual-species quantum test of the weak equivalence principle(WEP).With the FLM,the measurement is performed invariably at the midfringe,and the extraction of the phase shift for atom interferometers is linearized.For the simultaneous interferometers,this linearization enables a good common-mode rejection of vibration noise,which is usually the main limit for high precision WEP tests of the dual-species kind.We note that this method also allows for an unbiased determination of the gravity accelerations difference,which meanwhile is ready to be implemented.展开更多
Many studies on the diagnosis for machines have become important recently because of increased use of various complex industrial systems.The correlation information between sound and vibration is very important for ma...Many studies on the diagnosis for machines have become important recently because of increased use of various complex industrial systems.The correlation information between sound and vibration is very important for machine diagnosis.Usually,vibration pickups are attached directly to the machine in order to measure vibration data.However,in some cases,the sensors can not be attached directly on highly precise devices.In this study,a method to estimate the fluctuation of sound and vibration is proposed based on the measurement data of sound emitted from the machine under existence of background noise.The effectiveness of the proposed theory is experimentally confirmed by applying it to the observed data emitted from a rotational machine driven by an electric motor.展开更多
Vibration and noise aspects play a relevant role in the lifetime and comfort of urban areas and their resi-dents.Among the different sources,the one coming from the rail transit system will play a central concern in t...Vibration and noise aspects play a relevant role in the lifetime and comfort of urban areas and their resi-dents.Among the different sources,the one coming from the rail transit system will play a central concern in the following years due to its sustainability.Ground-borne vibration and noise assessment as well as techniques to mitigate them become key elements of the environmental impact and the global enlargement planned for the railway industry.This paper aims to describe and compare the different mitigation systems existing and reported in liter-ature through a comprehensive state of the art analysis providing the performance of each measure.First,an introduction to the ground-borne vibration and noise gen-erated from the wheel-rail contact and its propagation through the transmission path is presented.Then,the impact and the different ways of evaluating and assessing these effects are presented,and the insertion loss indicator is introduced.Next,the different mitigation measures at different levels(vehicle,track,transmission path and receiver)are discussed by describing their possible appli-cation and their efficiency in terms of insertion loss.Finally,a summary with inputs of how it is possible to address the future of mitigation systems is reported.展开更多
This paper introduces a novel method for fast calculating the electromagnetic forces in interior permanent magnet synchronous machines(IPMSMs)under pulse width modulation(PWM)voltage source inverter(VSI)supply based o...This paper introduces a novel method for fast calculating the electromagnetic forces in interior permanent magnet synchronous machines(IPMSMs)under pulse width modulation(PWM)voltage source inverter(VSI)supply based on the small-signal time-harmonic finite element analysis(THFEA),which has been successfully utilized for fast calculating the PWMinduced losses in silicon steel sheets and permanent magnets.Based on the small-signal THFEA,the functional relationships between high-frequency harmonic voltages(HFHVs)and corresponding airgap flux densities are established,which are used for calculating the flux density spectra caused by each HFHV in the PWM voltage spectra.Then,the superposition principle is applied for calculating the flux density spectra caused by fundamental currents and all HFHVs,which are converted to the electromagnetic force spectra at last.The relative errors between the force density spectra calculated with the proposed method and those obtained from traditional time-stepping finite element analysis(TSFEA)using PWM voltages as input are within 3.1%,while the proposed method is 24 times faster than the traditional TSFEA.展开更多
Reducing the self-noise and radiated noise of torpedo is an effective way to enhance its detection and concealment capabilities.After discussing the basic principle on noise and vibration control and main noise source...Reducing the self-noise and radiated noise of torpedo is an effective way to enhance its detection and concealment capabilities.After discussing the basic principle on noise and vibration control and main noise sources in torpedo,the application of damping treatment for noise and vibration absorption was proposed in this paper.Compared composite materials(damping and metal materials)used as segment joint,their different contributions to the damping performance of base structure were investigated.The results show that the damping material can be used as segment joint effectively in vibration control.Taking cantilever beam as an example,four different damping treatments were compared in natural frequency and damping loss factor,the results show the influences of different damping layer layouts on the structure damping performance,and offer a reference for the torpedo shell design.展开更多
The health monitoring has been studied to ensure integrity of design of engine structure by detection,quantification,and prediction of damages.Early detection of faults may allow the downtime of maintenance to be resc...The health monitoring has been studied to ensure integrity of design of engine structure by detection,quantification,and prediction of damages.Early detection of faults may allow the downtime of maintenance to be rescheduled,thus preventing sudden shutdown of machines.In cylinder pressure developed,vibrations and noise emissions data provide a rich source of information about condition of engines.Monitoring of vibrations and noise emissions are novel non-intrusive methodologies for which positioning of various transducers are important issue.The presented work shows applicability of these diagnosis methodologies adopted in case of diesel engines.The effects of changing various fuel injection parameters was analyzed.Scope of using non-intrusive technique has been analyzed by changing locations of microphone.Novelty of this worklies in exploring signal processing methods for various locations around the engine test set up.Various frequency ranges of contributing noise and vibration sources were identified.Time-Frequency analysis showed the onset of various cyclic.Based on the identification of various frequency bands,it is possible to device suitable filters in order to extract more information.展开更多
For years,friction-induced vibration and noise(FIVN)has puzzled many researchers in academia and industry.Several mechanisms have been proposed for explaining its occurrence and quantifying its frequencies,notably for...For years,friction-induced vibration and noise(FIVN)has puzzled many researchers in academia and industry.Several mechanisms have been proposed for explaining its occurrence and quantifying its frequencies,notably for automotive brake squeal,clutch squeal,and even rail corrugation.However,due to the complex and complicated nature of FIVN,there is not yet one fundamental mechanism that can explain all phenomena of FIVN.Based on experimental results obtained on a simple test structure and corresponding numerical validation using both complex eigenvalue analysis(CEA)and transient dynamic analysis(TDA),this study attempts to propose a new fundamental mechanism for FIVN,which is the repeated cycles of partial detachment and then reattachment of the contact surfaces.Since friction is ubiquitous and FIVN is very common,the insight into FIVN reported in this paper is highly significant and will help establish effective means to control FIVN in engineering and daily life.展开更多
An optimized structure to weaken the vibration and noise of a new asymmetric permanent magnet-assisted synchronous reluctance motor(PMaSynRM)is proposed.The new asymmetric PMaSynRM has the advantages of a low torque r...An optimized structure to weaken the vibration and noise of a new asymmetric permanent magnet-assisted synchronous reluctance motor(PMaSynRM)is proposed.The new asymmetric PMaSynRM has the advantages of a low torque ripple and high fault tolerance.However,the asymmetric structure generates an unbalanced magnetic force(UMF),which results in vibration and noise problems.In this study,the vibration and noise of the motor are analyzed and optimized.First,the radial pressure is analyzed,and an optimized structure is proposed.The electromagnetic performance of the motor before and after optimization is analyzed using the finite element method.Second,a three-dimensional model is established,and modal analysis is conducted considering the orthotropy of the stator and effective windings.Finally,the vibration and noise are simulated and analyzed,and the validity of the analysis results is verified experimentally.The analysis results indicate that the optimized motor realizes a reduction in the motor vibration and noise.展开更多
A Revised Edition of the now-classical 1971 text edited by L.Beranek,Noise and Vibration Control,has been published by the Institute of NoiseControl Engineering.Noise and Vibration Control is of great value to designa...A Revised Edition of the now-classical 1971 text edited by L.Beranek,Noise and Vibration Control,has been published by the Institute of NoiseControl Engineering.Noise and Vibration Control is of great value to designand safety engineers,consultants,scientists,architects,governmentresearchers,public officials and others concerned with the control of noiseemitted by machinery and with control of environmental noise in buildings,in the workplace,near airports and highways,and in the community.This展开更多
In the automotive and transport industry,braking noise and vibrations are persisting issues and difficult to control.Automo-tive engineers and researchers are putting considerable effort into overcoming these problems...In the automotive and transport industry,braking noise and vibrations are persisting issues and difficult to control.Automo-tive engineers and researchers are putting considerable effort into overcoming these problems,and significant breakthroughs have been made in this area.In this study,M-shaped grooves were bionically designed and manufactured on the frictional surfaces of four automotive brake discs using a laser machine.Various tests were conducted to characterize the physical and mechanical performance of the modified discs along with their noise and vibration responses.The experimental results demonstrate that discs with laser-machined grooved surfaces have better surface hardness and residual stress reduction than discs with un-grooved surfaces.Significant improvement in the braking performance was observed in terms of disc thickness variation,friction and wear,noise,and vibration reduction.It is concluded that the reduction in braking noise and vibrations is mainly caused by the reduction in the coefficient of friction and wear,increase in damping ratio,and improvement of disc thickness variation of the brake disc by laser surface grooving.展开更多
Amorphous alloy(AA)is attracting more and more attention in electrical machines due to its excellent low loss characteristics.This paper overviews advances on AA electrical machines over the last 30 years,with particu...Amorphous alloy(AA)is attracting more and more attention in electrical machines due to its excellent low loss characteristics.This paper overviews advances on AA electrical machines over the last 30 years,with particular reference to new and novel topologies and processing techniques of AA electrical machines and their key technologies.These include current states and trends for radial-flux AA electrical machines,axial-flux AA electrical machines,influences of processing techniques on electrical performance of AA iron cores,the characteristics of loss and vibration and noise of AA core and AA machines,optimum design of AA electrical machines,etc.The paper highlights the application prospects of the AA electrical machines.展开更多
Because of high efficiency, energy conservation,simple operation, wide application range, and small size,the high-speed universal pulverizer has been well receivedby customers. However, its electrical motor can overhe...Because of high efficiency, energy conservation,simple operation, wide application range, and small size,the high-speed universal pulverizer has been well receivedby customers. However, its electrical motor can overheatwhen working, which hinders continuous operation of thepulverizer. In this study, a series of efforts were made toaddress this problem. Firstly, a detailed analysis of theworking principle of the pulverizer was conducted and anoptimization plan was proposed, consisting in punchingventilation holes on the surface of the original pulverizer.Simulations of the pulverizer flow field before and afteroptimization were performed. The hydrodynamic simula-tion results were used to conduct a steady state thermalanalysis of the pulverizer, investigating the influence of theflow field on heat transfer. Additionally, experimentalinvestigations were conducted on the pulverizer before andafter optimization in order to measure and compare theparameters (motor working temperature, wind speed andtemperature of the motor cooling system, vibration, noise,and pulverizing degree of the material) influencing theperformance of the pulverizer. The numerical simulationresults showed an increment in heat transfer caused byincrement in air flow volume and velocity when air wasinjected into the pulverizer through bottom and side holes.Experimental results showed that the pulverizer with airinjection through holes had the best performance whentemperature, vibration, and refinement effect were consid-ered as performance indicators.展开更多
基金Supported by the National Science and Technology Major Project(No.2017-IV-0010-0047)China Postdoctoral Science Foundation FundedProject(No.2020M670113)Fundamental Research Funds for the Central Universities(No.JY2105)。
文摘When the actual installation center distance between a pair of spur gears is greater than the theoretical center distance,backlash increases,leading to increased vibration and noise.The structural parameters of an integral squeeze film damper(ISFD)were designed with the stiffness of rigid support as reference to investigate the effect of an ISFD on the dynamic characteristics of a spur gear transmission system with center-distance installation error.A spur gear test bench with center distance-error was built to investigate the vibration and noise reduction characteristics of ISFD.The experimental results indicate that,compared with a rigid support,the ISFD can reduce vibration by approximately 40%and noise by approximately 5 d B.ISFD can effectively absorb the impact energy caused by an increase of in backlash,which is conducive to the stable operation of the spur gear transmission system.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.41127002,11574099,and 11474115)the National Basic Research Program of China(Grant No.2010CB832806)
文摘We theoretically investigate the application of the fringe-locking method(FLM) in the dual-species quantum test of the weak equivalence principle(WEP).With the FLM,the measurement is performed invariably at the midfringe,and the extraction of the phase shift for atom interferometers is linearized.For the simultaneous interferometers,this linearization enables a good common-mode rejection of vibration noise,which is usually the main limit for high precision WEP tests of the dual-species kind.We note that this method also allows for an unbiased determination of the gravity accelerations difference,which meanwhile is ready to be implemented.
文摘Many studies on the diagnosis for machines have become important recently because of increased use of various complex industrial systems.The correlation information between sound and vibration is very important for machine diagnosis.Usually,vibration pickups are attached directly to the machine in order to measure vibration data.However,in some cases,the sensors can not be attached directly on highly precise devices.In this study,a method to estimate the fluctuation of sound and vibration is proposed based on the measurement data of sound emitted from the machine under existence of background noise.The effectiveness of the proposed theory is experimentally confirmed by applying it to the observed data emitted from a rotational machine driven by an electric motor.
基金financially supported by the European Union’s Horizon 2020 research and innovation programme under the Marie Sk?odowska-Curie grant agreement No INSPIRE813424。
文摘Vibration and noise aspects play a relevant role in the lifetime and comfort of urban areas and their resi-dents.Among the different sources,the one coming from the rail transit system will play a central concern in the following years due to its sustainability.Ground-borne vibration and noise assessment as well as techniques to mitigate them become key elements of the environmental impact and the global enlargement planned for the railway industry.This paper aims to describe and compare the different mitigation systems existing and reported in liter-ature through a comprehensive state of the art analysis providing the performance of each measure.First,an introduction to the ground-borne vibration and noise gen-erated from the wheel-rail contact and its propagation through the transmission path is presented.Then,the impact and the different ways of evaluating and assessing these effects are presented,and the insertion loss indicator is introduced.Next,the different mitigation measures at different levels(vehicle,track,transmission path and receiver)are discussed by describing their possible appli-cation and their efficiency in terms of insertion loss.Finally,a summary with inputs of how it is possible to address the future of mitigation systems is reported.
基金supported in part by the National Natural Science Foundation of China under projects 51907053by Natural Science Foundation of Jiangsu Province of China under Project BK20190489+1 种基金by the Fundamental Research Funds for the Central Universities under grant B200202167by the China Postdoctoral Science Foundation under grant no.2019M661708。
文摘This paper introduces a novel method for fast calculating the electromagnetic forces in interior permanent magnet synchronous machines(IPMSMs)under pulse width modulation(PWM)voltage source inverter(VSI)supply based on the small-signal time-harmonic finite element analysis(THFEA),which has been successfully utilized for fast calculating the PWMinduced losses in silicon steel sheets and permanent magnets.Based on the small-signal THFEA,the functional relationships between high-frequency harmonic voltages(HFHVs)and corresponding airgap flux densities are established,which are used for calculating the flux density spectra caused by each HFHV in the PWM voltage spectra.Then,the superposition principle is applied for calculating the flux density spectra caused by fundamental currents and all HFHVs,which are converted to the electromagnetic force spectra at last.The relative errors between the force density spectra calculated with the proposed method and those obtained from traditional time-stepping finite element analysis(TSFEA)using PWM voltages as input are within 3.1%,while the proposed method is 24 times faster than the traditional TSFEA.
文摘Reducing the self-noise and radiated noise of torpedo is an effective way to enhance its detection and concealment capabilities.After discussing the basic principle on noise and vibration control and main noise sources in torpedo,the application of damping treatment for noise and vibration absorption was proposed in this paper.Compared composite materials(damping and metal materials)used as segment joint,their different contributions to the damping performance of base structure were investigated.The results show that the damping material can be used as segment joint effectively in vibration control.Taking cantilever beam as an example,four different damping treatments were compared in natural frequency and damping loss factor,the results show the influences of different damping layer layouts on the structure damping performance,and offer a reference for the torpedo shell design.
文摘The health monitoring has been studied to ensure integrity of design of engine structure by detection,quantification,and prediction of damages.Early detection of faults may allow the downtime of maintenance to be rescheduled,thus preventing sudden shutdown of machines.In cylinder pressure developed,vibrations and noise emissions data provide a rich source of information about condition of engines.Monitoring of vibrations and noise emissions are novel non-intrusive methodologies for which positioning of various transducers are important issue.The presented work shows applicability of these diagnosis methodologies adopted in case of diesel engines.The effects of changing various fuel injection parameters was analyzed.Scope of using non-intrusive technique has been analyzed by changing locations of microphone.Novelty of this worklies in exploring signal processing methods for various locations around the engine test set up.Various frequency ranges of contributing noise and vibration sources were identified.Time-Frequency analysis showed the onset of various cyclic.Based on the identification of various frequency bands,it is possible to device suitable filters in order to extract more information.
基金the National Natural Science Foundation of China(No.11672052)Natural Science Foundation of Zhejiang Province(LQ22E050012)are gratefully acknowledged.
文摘For years,friction-induced vibration and noise(FIVN)has puzzled many researchers in academia and industry.Several mechanisms have been proposed for explaining its occurrence and quantifying its frequencies,notably for automotive brake squeal,clutch squeal,and even rail corrugation.However,due to the complex and complicated nature of FIVN,there is not yet one fundamental mechanism that can explain all phenomena of FIVN.Based on experimental results obtained on a simple test structure and corresponding numerical validation using both complex eigenvalue analysis(CEA)and transient dynamic analysis(TDA),this study attempts to propose a new fundamental mechanism for FIVN,which is the repeated cycles of partial detachment and then reattachment of the contact surfaces.Since friction is ubiquitous and FIVN is very common,the insight into FIVN reported in this paper is highly significant and will help establish effective means to control FIVN in engineering and daily life.
文摘An optimized structure to weaken the vibration and noise of a new asymmetric permanent magnet-assisted synchronous reluctance motor(PMaSynRM)is proposed.The new asymmetric PMaSynRM has the advantages of a low torque ripple and high fault tolerance.However,the asymmetric structure generates an unbalanced magnetic force(UMF),which results in vibration and noise problems.In this study,the vibration and noise of the motor are analyzed and optimized.First,the radial pressure is analyzed,and an optimized structure is proposed.The electromagnetic performance of the motor before and after optimization is analyzed using the finite element method.Second,a three-dimensional model is established,and modal analysis is conducted considering the orthotropy of the stator and effective windings.Finally,the vibration and noise are simulated and analyzed,and the validity of the analysis results is verified experimentally.The analysis results indicate that the optimized motor realizes a reduction in the motor vibration and noise.
文摘A Revised Edition of the now-classical 1971 text edited by L.Beranek,Noise and Vibration Control,has been published by the Institute of NoiseControl Engineering.Noise and Vibration Control is of great value to designand safety engineers,consultants,scientists,architects,governmentresearchers,public officials and others concerned with the control of noiseemitted by machinery and with control of environmental noise in buildings,in the workplace,near airports and highways,and in the community.This
基金This study was supported by the Science and Technology Committee of Shanghai Municipal Key Project(1806052400)the NSFC Project(51275126).
文摘In the automotive and transport industry,braking noise and vibrations are persisting issues and difficult to control.Automo-tive engineers and researchers are putting considerable effort into overcoming these problems,and significant breakthroughs have been made in this area.In this study,M-shaped grooves were bionically designed and manufactured on the frictional surfaces of four automotive brake discs using a laser machine.Various tests were conducted to characterize the physical and mechanical performance of the modified discs along with their noise and vibration responses.The experimental results demonstrate that discs with laser-machined grooved surfaces have better surface hardness and residual stress reduction than discs with un-grooved surfaces.Significant improvement in the braking performance was observed in terms of disc thickness variation,friction and wear,noise,and vibration reduction.It is concluded that the reduction in braking noise and vibrations is mainly caused by the reduction in the coefficient of friction and wear,increase in damping ratio,and improvement of disc thickness variation of the brake disc by laser surface grooving.
基金the National Natural Science Foundation of China(51307111,51677122)National key research and development program(2016YFB0300503).
文摘Amorphous alloy(AA)is attracting more and more attention in electrical machines due to its excellent low loss characteristics.This paper overviews advances on AA electrical machines over the last 30 years,with particular reference to new and novel topologies and processing techniques of AA electrical machines and their key technologies.These include current states and trends for radial-flux AA electrical machines,axial-flux AA electrical machines,influences of processing techniques on electrical performance of AA iron cores,the characteristics of loss and vibration and noise of AA core and AA machines,optimum design of AA electrical machines,etc.The paper highlights the application prospects of the AA electrical machines.
文摘Because of high efficiency, energy conservation,simple operation, wide application range, and small size,the high-speed universal pulverizer has been well receivedby customers. However, its electrical motor can overheatwhen working, which hinders continuous operation of thepulverizer. In this study, a series of efforts were made toaddress this problem. Firstly, a detailed analysis of theworking principle of the pulverizer was conducted and anoptimization plan was proposed, consisting in punchingventilation holes on the surface of the original pulverizer.Simulations of the pulverizer flow field before and afteroptimization were performed. The hydrodynamic simula-tion results were used to conduct a steady state thermalanalysis of the pulverizer, investigating the influence of theflow field on heat transfer. Additionally, experimentalinvestigations were conducted on the pulverizer before andafter optimization in order to measure and compare theparameters (motor working temperature, wind speed andtemperature of the motor cooling system, vibration, noise,and pulverizing degree of the material) influencing theperformance of the pulverizer. The numerical simulationresults showed an increment in heat transfer caused byincrement in air flow volume and velocity when air wasinjected into the pulverizer through bottom and side holes.Experimental results showed that the pulverizer with airinjection through holes had the best performance whentemperature, vibration, and refinement effect were consid-ered as performance indicators.