第39卷第6期英文摘要

AnOverviewofPolygonalWearandGeneratedNoiseofTrainWheels

LIYanfu,MENTianli

(Department of Industrial Engineering, Tsinghua University Beijing, 100084, China)

AbstractThe paper is an overview of polygonal wear and generated noise of train wheels in recent years. Besides explaining the related concepts and definitions of wheel polygonal wear, the paper also lists the causes of polygonal wear and the relationship between polygonal wear and noise. The related domestic and abroad researches on train wheel polygonal wear mainly focus on the effect of wheel polygonal wear on wheel-rail dynamics, the generation and development mechanism of wheel polygonal wear and the detection and evaluation of wheel polygonal wear. In this paper, noise generated by vibration, vibration caused by wheel polygonal wear and noise arising from wheel polygonal wear are reviewed. The domestic and abroad research progress on train maintenance are both summarized. The paper also gives some advice on overhaul of trains with polygonal wear in wheels.

Keywordstrain; polygonal wear; noise; relationship

PracticalImprovementoftheRandomDecrementTechniqueinModalIdentification

CHENTaicong1, 2,SHENWenjie2

(1. State Key Laboratory of Subtropical Building Science, South China University of Technology Guangzhou, 510641, China)

(2. School of Civil Engineering and Transportation, South China University of Technology Guangzhou, 510641, China)

AbstractIn view of the singular value problem of acceleration random decrement (RD) signature and the extraction problem of structural real mode shapes in the practice of modal identification, a corresponding signature truncation method and a minimum distance method are proposed to improve the modal identification effect. Firstly, the reason of the singular value of acceleration RD signature is analyzed, and the signature truncation method is proposed for the subsequent processing with the Ibrahim time domain technology. Then, by using an optimization model, the computation formula of the minimum distance method is established to facilitate the extraction of structural real mode shapes from the identified complex mode shapes. Finally, the numerical example and model experiment are applied to verify the feasibility of the proposed methods. The results show that a rational value of the truncation ratio for the acceleration RD signature would be 1/200～1/50, and the minimum distance method is applicable with high noise resistance for extracting real mode shapes under all kinds of responses.

Keywordsmodal identification; random decrement; complex mode shape; real mode shape; Ibrahim time domain method

AccelerationResponseSpectrumforPredictingFloorVibrationUnderStochasticCrowdLoad

ZHANGZhiqiang1,2,ZHOUChen1,2,ZHANGXiaofeng3,LIAiqun1,4

(1. School of Civil Engineering, Southeast University Nanjing, 210096, China)

(2. Key Laboratory of Concrete and Pre-stressed Concrete Structures of the Ministry of Education,

Southeast University Nanjing, 210096, China)

(3. Department of Architectural Engineering and Construction Science, Kansas State University KS, 66506, USA)

(4. School of Civil and Transportation Engineering, Beijing University of Civil Engineering and Architecture Beijing, 100044, China)

AbstractQuantities of stochastic walking curves are generated with Monte-Carlo method, and 1 000 root-mean-square acceleration response spectrum in the vertical vibration direction of the test floor is calculated. Actual projects are studied to verify the results using response-spectrum method, and three cases of floor construction are adopted in this paper. The results of the measuring points using response-spectrum method are compared with other measuring values under the most unfavorable conditions and the theoretical values calculated by finite element method, which are all consistent. The method is helpful to obtain the position of response and to discover the main vibration mode which causes the structural maximum response, and it is also useful for the structural vibration control. The suggested spectrum-based approach can be used for the acceleration response of large span floor under a stochastic walking load.

Keywordsstochastic crowd excitation; Monte-Carlo method; response spectrum curve; long-span floor

NumericalStudiesofSuspenders′StressImpactFactorofTrainandArchBridgeCoupledSystems

ZHUZhihui1,2，LUOSihui1，ZHANGLei1，WANGLidong1,2，YUZhiwu1,2，MENGXin3

(1. School of Civil Engineering, Central South University Changsha, 410075, China)

(2. National Engineering Laboratory for High Speed Railway Construction, Central South University Changsha, 410075, China)

(3. Railway Engineering Research Institute, China Academy of Railway Sciences Corporation Limited Beijing, 100081, China)

AbstractBased on the vehicle-bridge coupling vibration theory and the field test of ground-based microwave radar, the stress impact coefficient of suspender of high-speed railway arch bridge is studied. The train and track-bridge are modeled by multi-rigid-body dynamics and finite element method, respectively, and the train-track-bridge coupled system model is established based on the equivalent Hertz linear wheel/rail contact model. The displacements of the top and bottom of the suspenders are tested simultaneously by the ground-based microwave radar system. The dynamic characteristics of the bridge, the time-history of stress and the stress impact factor of suspenders are obtained. The experimental data of ground-based microwave radar are compared to verify the correctness of the theoretical model. Based on the model, the influences of driving speed, single or double line driving and track irregularity on the stress impact factor of the suspenders are analyzed. The results show that the stress impact factor of suspender increases with the increase of vehicle speed. When the speed is 300 km/h, the stress impact factor of the suspender increases significantly due to the resonance of the axle. Due to the low static stress of suspender caused by train load, the impact factor of suspenders during single-line driving is larger than that of the double line. The German low-interference orbit spectrum sample has little effect on the stress-impact coefficient of the suspenders, but the stress impact factor increases significantly with the deterioration of track smoothness.

Keywordstrain-track-bridge coupled system; ground-based microwave radar; arch bridge; suspender; impact factor

ExperimentalTestsofDampedMillingCutterBasedonEmbeddedPassiveDamper

YANGYiqing，PIANYawei,WANGYunfei

(School of Mechanical Engineering and Automation, Beihang University Beijing, 100191, China)

AbstractA design of damped milling cutter embedded with passive damper is proposed, and an optimal structural design is achieved after performing modal tests on the damper. The dynamic characteristics of the damped milling cutter in different directions are studied. Moreover, the cutting experiments of aluminum alloy and titanium alloy with different cutting parameters are accomplished. Compared with the non-damped milling cutter, the machining noise, cutting force and surface roughness of damped milling cutter are reduced by 52.1%, 49.5% and 73.4%, respectively, when machining aluminum. The damped milling cutter can machine the titanium in a stable condition while non-damped cutter has an obvious chatter vibration with the same cutting parameters.

Keywordsdamped milling cutter; passive damper; modal test; cutting experiment

Multi-channelTransmissionMethodforMechanicalVibrationWirelessSensorNetworksBasedonTimeSynchronizedScheduling

TANGBaoping,ZHOUYanjiang,XIAOXin,DENGLei

(State Key Laboratory of Mechanical Transmission, Chongqing University Chongqing, 400030, China)

AbstractAiming at the problems that machine vibration wireless sensor networks has a low network transmission rate in multi-hop application due to the intense channel competition, a multi-channel data transmission method based on time synchronized scheduling is proposed to improve the multi-hop transmission performance for clock synchronization accuracy, network scheduling efficiency and channel interference. The clock synchronization method for multi-hop network based on beacon timing compensation is used to realize the whole network synchronous scheduling of data transmission. The data transmission scheduling method of father-son link timing rotation is utilized to maximize the effective transmission time. Furthermore, the interference minimization channel allocation method is adopted to realize the transmission channel allocation in multi-hop networks and to avoid the influence to the parallel data transmission from adjacent frequency interference. In addition, the packet loss detection retransmission mechanism is used to guarantee the reliability of data transmission and avoid vibration data packet dropout. Multi-channel data transmission performance test results show that the method can improve the data transmission rate of multi-hop network from 10 kbps to 70 kbps, and meet the data transmission requirements of multi-hop mechanical vibration wireless sensor networks.

Keywordsmechanical vibration; wireless sensor networks; time synchronization; multi-channel; data transmission

Time-FrequencyNonstationarityStochasticGroundMotionModelandApplicationinStructuralRandomVibration

HEHaoxiang,FANShaoyong,YANWeiming

( Beijing Laboratory of Earthquake Engineering and Structure Retrofit, Beijing University of Technology Beijing, 100124, China)

AbstractGround motion involves significant nonstationary in time domain and frequency domain. The traditional uniform modulation model cannot fully characterize the nonstationary in both time domain and frequency domain, which debases the accuracy and precision of structural random vibration analysis. In order to overcome the above defects, a nonuniform modulated ground motion model is established, which is generated by the dot product of the multi-peak smooth intensity envelope and the nonstationary noise signal. The new model can fully represent the oscillation and attenuation characteristics of earthquake wave in time domain, at the same time, its spectral characteristics are close to the real values. Based on this study, the nonstationary evolution spectrum model is established, which simultaneously sets the time and frequency as variables. The analysis results show that these two models are superior to the uniform modulation model in both time domain and frequency domain. In view of the form and characteristics of the above seismic stochastic process model, the analytic method for solving the traditional structural vibration response is improved. Through a large number of examples, it is proved that the nonstationary characteristics in both time and frequency domains cannot be fully obtained when the structural random response is calculated according to the uniform modulation model, and the unsafe results are usually obtained. On the contrary, more accurate structural response characteristics and more detailed evolution process can be obtained when the two new improved models are used.

Keywordsground motion; nonstationarity; random vibration; intensity envelope; uniform modulation; evolution spectrum

CouplingDynamicModelingandParameterIdentificationofaFlexibleManipulatorSystemwithHarmonicDrive

LOUJunqiang1,ZHOUYoupeng1,ZHANGZhenzhen1,CHENTehuan1,YANGYiling1,WEIYanding2

(1. College of Mechanical Engineering and Mechanics, Ningbo University Ningbo, 315211, China)

(2. Institute of Contemporary Manufacturing Engineering, Zhejiang University Hangzhou, 310027, China)

AbstractIn order to study the coupling dynamic modeling method of a flexible manipulator system with harmonic drive, both the driven model parameters of the harmonic joint and the coupling vibration model of the flexible manipulator are identified. Coulomb friction of the joint is identified using step current excitation and uniform rotation experiments in a low speed. Then, the transfer function model of the harmonic joint is established and identified using a pseudo-random binary sequence excitation, and the moment of inertia and viscous friction coefficient of the harmonic joint are included in this model. Moreover, the predict outputs of the obtained model are in good agreement with the experimental results. The linear relationships between the strain output of the flexible manipulator and the coupling torque are presented from theoretical derivation. The transfer function model from the angular displacement of the servo motor to the strain output of the flexible manipulator are identified. Experimental results show these identified models match well with the proposed structure, both in the time and frequency domains. As a result, this coupling dynamic modeling method of the flexible manipulator system with harmonic drive is accomplished by integrating those two identification transfer function models.

Keywordsharmonic drive; flexible manipulator; system identification; coupling dynamic modeling

QuantizationoftheMaterialNonlinearityBasedontheGeometricCharacteristicofDuffingvan-der-polSystem

BOLin,LIZhaoxin,LIUXiaofeng

(The State Key Laboratory of Mechanical Transmission, Chongqing University Chongqing, 400044, China)

AbstractTraditional signal processing methods are applied to nonlinear Lamb waves, but the precision and noise immunity are insufficient. Duffing van-der-pol system is a kind of nonlinear dynamical system, and a method is proposed to detect the weak changes of nonlinear Lamb wave, which are caused by the material nonlinearity based on this system. Due to the limitation of traditional method, the geometric characteristics of the system (the average periodic area) are used as the characteristic parameters to enhance the weak second harmonic and to quantify the nonlinear characteristics of the material. In this paper, the internal force of the system is determined by bifurcation diagram. Then, according to the system phase trajectory, the existence of the second harmonic is determined by the system state identified, and the geometric characteristics are used to calculate the amplitude of second harmonic. Furthermore, the linear relationship between the second harmonic amplitude and the geometric characteristic parameters is analyzed. Ultimately, the nonlinear coefficient of the material can be acquired accurately. Compared with the wavelet transform and Kalman filtering, this method can still maintain high precision under strong noise.

KeywordsDuffing van-der-pol oscillator; average area index; nonlinear Lamb waves; quantification study

DoubleRandomDynamicTheoreticalStudyforUncertaintyCeramicThermalProtectionSystem

HUANGJie1,YAOWeixing2,CHENYan1,3,KONGBin1,3

(1. Key Laboratory of Fundamental Science for National Defense-Advanced Design Technology of Flight Vehicle, Nanjing University of Aeronautics and Astronautics Nanjing, 210016, China)

(2. State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics Nanjing, 210016, China)

(3. AVIC Chengdu Aircraft Design and Research Institute Chengdu, 610091, China)

AbstractIn order to study the probability distributions on the dynamic responses of the uncertainty ceramic thermal protection system (TPS), a double random dynamic theoretical model for uncertainty TPS under the outer random excitations is presented in this paper. In the theoretical model, the tile is simplified as a mass point, the strain isolation pad (SIP) is simplified as a linear spring and a damping unit, and the above mass point, the stiffness of spring and the damping all obey the normal distribution. The probability distributions for acceleration of the tile and the dynamic stress of SIP are studied by a perturbation method, and the key problem is to obtain the sensitivity analysis of the mean responses to the random parameters of TPS. The theoretical method and Monte Carlo numerical method are used to calculate the probability distributions of responses. The results show that the mean values and standard deviations of the responses calculated by theoretical method match very well with that calculated by Monte Carlo numerical method, which verifies the correctness and analysis accuracy of the dynamic theoretical model presented in this paper. Finally, the works in this paper provide a theoretical basis for the analysis of the uncertainty acceleration of tile, the uncertainty dynamic strength of SIP and the uncertainty dynamic integrity of TPS.

Keywordsuncertainty；thermal protection system；dynamic theoretical model；tile；strain isolation pad

AnalysisMethodBasedonSolvingGearRattleinTransmissionofaDrivelineSystem

WANLixiang1,WANGBo1,LIUXuelai2,HOUQiufeng3,YAOShicong4,SHANGGUANWenbin2

(1. School of Mechanical Engineering, Southwest Jiaotong University Chengdu, 610031, China)

(2. School of Mechanical and Automotive Engineering, South China University of Technology Guangzhou, 510641, China)

(3. Ningbo Hongxie Co., Ltd. Ningbo, 315807, China)

(4. China Automotive Engineering Research Institute Co., Ltd. Chongqing, 401122, China)

AbstractA driveline system model of six degrees of freedom is established, and the meshing clearance between the geared gears in the transmission are modeled. The dynamic response is calculated using the developed model to estimate angular acceleration for each rigid body in the model. Taking the angular acceleration of the input shaft for transmission as an evaluation index, the influence of model parameters on the angular acceleration of the input shaft is studied. Based on the developed model, the parameters of the moments of inertia for flywheel and stiffness of clutch are optimized by sequential quadratic programming. Then, in the experiment, the torsional angle acceleration of the input shaft for transmission, the vibration acceleration of transmission and the sound pressure at the transmission side at an engine compartment are measured and compared on the baseline clutch and the optimized clutch to measure. The results show that the angular acceleration amplitude of the input shaft and the gear impact of unloaded gear rattle can be effectively decreased by increasing the inertia of the flywheel and the damping torque of clutch, or by reducing the inertia of the unloaded gear on the output shaft. The unloaded gear rattle is decreased greatly using the optimized clutch, which validates the calculation and experiment methods of this study.

Keywordstransmission; unloaded gear; gear rattle; clutch; model for geared pairs

Locomotion-ModeRecognitionBasedonFishSwarmAlgorithmandExtremeLearningMachine

LIULei1,2，CHENZengqiang2，YANGPeng3，LIUZuojun3

(1. School of Building Environmental Engineering, Zhengzhou College of Light Industry Zhengzhou, 450002, China)

(2. College of Artificial Intelligence, Nankai University Tianjin, 300350, China)

(3. School of Artificial Intelligence and Data Science, Hebei University of Technology Tianjin, 300130, China)

AbstractIn light of the accuracy and timeliness of locomotion-mode recognition of intelligent prosthesis, a pattern recognition method based on the fish swarm (FA) algorithm is proposed to optimize the extreme learning machine (ELM). First, the features of tensor projection are extracted, and the rationality of the selection of features is analyzed. Then, principal component analysis is used to reduce the dimension. Finally, treads of walking on-ground, upstairs, downstairs, uphill, and downhill are recognized using the learning machine of FA-ELM. The recognition accuracy is 97.45%. The comparison with ELM and other classifiers shows that FA-ELM recognizes more accurately.

Keywordssurface electromyography(sEMG); extreme learning machine(ELM); fish swarm algorithm(FA); locomotion-mode recognition; intelligent prosthesis

ContinuousScanningLaserDopplerVibrationMeasurementUnderMulti-frequencyExcitation

LIFan1，ZANGChaoping1，ZHANGZhong2

(1. College of Energy & Power Engineering, Nanjing University of Aeronautics & Astronautics Nanjing, 210016, China)

(2. Beijing Institute of Structure and Environment Engineering Beijing, 100076, China)

AbstractA multi-frequency excitation method is proposed for higher efficiency of the continuous scanning laser Doppler vibration (CSLDV) measurement. First, based on the principle of a single frequency excitation for the CSLDV test, the approach of CSLDV measurement under a multi-frequency excitation is explored and the structural operational deflection shape(ODS) extraction based on a multi-frequency excitation is developed. Then, the simulation test of a beam structure is used to verify the effectiveness of the method. Finally, the experiments based on CSLDV and SLDV are both conducted on a cantilever beam structure. The results show that the structural ODS can be obtained accurately by both tests with the fact that the CSLDV method is more efficient and has higher spatial resolution than that of the SLDV method. This approach shows practical value for further engineering applications.

Keywordsmulti-frequency; continuous scanning; laser Doppler; vibration test; operational deflection shape

BlindSourceSeparationBasedonSparseFeaturefortheFaultSignalsoftheContinuousMills

YANBaokang，ZHOUFengxing，NINGBowen，LIWeigang

(School of Information Science and Engineering, Wuhan University of Science and Technology Wuhan, 430081, China)

AbstractThe stability of a rolling mill plays a decisive role in the quality of rolled products, but signals monitoring the status of the rolling mill have very strong coupling. In this case, to separate the complex signals into independent status signals of each mill is essential to realize the status monitoring and fault diagnosis for rolling mill. In this paper, a technical scheme for separating fault signals of continuous rolling mills based on sparse features is proposed, and simulation and field verification are carried out. First, the weak impulses of the mixed signals are extracted through the method of sparse decomposition based on spectrum segmentation; second, the selected atoms are sorted out according to certain rules to get the sparse matrix of mixed signals; then, the selected atoms are clustered according to the similarity of sparse atoms to determine the number of blind sources; finally, the mixing matrix is estimated according to the sparse matrix and the number of blind sources to realize the blind source separation of mixed signals.

Keywordscontinuous rolling mill; sparse feature; sparse decomposition; blind source separation; fault diagnosis

ExperimentalStudyonVibrationControlofCurvedGirderBridgeBasedonParticleDamper

XUWeibing，YANWeiming，HEHaoxiang，CHENYanjiang

(Beijing Key Laboratory of Earthquake Engineering and Structural Retrofit，Beijing University of Technology Beijing, 100024, China)

AbstractA 1/10 scale test model of a typical curved girder bridge is designed and manufactured in order to introduce particle damper into the vibration control of the curved girder bridge. A series of shaking table tests are carried out based on the model bridge with and without the curved-capsule particle damper (CPD) respectively. The results show that CPD has the advantages of simple structure, convenient installation applied to the curved girder bridge; CPD can play control effect along the longitudinal and transverse direction under traditional and near-fault seismic waves excitation, and CPD has good directional adaptability; the variability of CPD control effect is greater under the near-fault seismic waves excitation because of the large pulses, when there is a large velocity pulse near the natural frequency of the structure, better control effect of CPD can be received.

Keywordscurved girder bridge; particle damper; near-fault earthquake; directional adaptability

TestExperimentsofSensingCharacteristicsofSingle-ElectrodeofUltrasonicMotorinShockEnvironment

SUNDong1,TANGYujuan2,WANGXinjie1,WANGJiong1,FUHaomin1

(1. School of Mechanical Engineering, Nanjing University of Science and Technology Nanjing, 210094, China)

(2. School of Intelligent Science and Control Engineering, Jinling Institute of Technology Nanjing, 211169, China)

AbstractAn idea that single-electrode can be used as an acceleration sensor is proposed in this paper. The voltage sensitivity of the single-electrode sensor is presented based on the second type piezoelectric equation and the deflection differential equation of the annular plate. The resonant frequency of the sensor is obtained with the finite element method. The experimental platform is set up to calibrate the sensor. Experiment results show that the output of single-electrode can maintain a good linear relationship with acceleration while the pulse width of acceleration exceeds 500μs. However, there is interference besides useful signals. A low-pass digital filter is designed to effectively filter out the noise. The filtered signal still has a good linear relationship with acceleration. The research results expand the function of the ultrasonic motor and promote the application of ultrasonic motor in the shock environment.

Keywordssingle-electrode; sensor; impact; signal processing

AnalysisofAbnormalVibrationofanAero-engineTestSample

MAHuifang,HUANGWei,YULei,YUXueran,CAOYi

(AECC Commercial Aircraft Engine Co., Ltd. Shanghai, 200241, China)

AbstractIn light of the risk of and reasons for the abnormal vibration, an analysis of this vibration is conducted. Signal processing methods such as FFT, conversion between different vibration data types, orbits of axis, waterfall map, and waterfall map with characteristic frequencies of bearing are used to reveals the features of abnormal vibration. Then, the details of the structure and the data of multi-test points are analyzed, and the type of vibration is determined to be resonance on the waterfall map. The modals of the vibration components computed with FEA(finite element analysis) and the bearing’s characteristic frequencies with theoretical formulas lead to the conclusion that the bearing results in the abnormal vibration. Finally, detection results of bearing after disassembling are supplied to show that the methods and procedure of analysis are reasonable. The analysis of the abnormal vibration is referenced for vibration faults diagnosis.

Keywordsvibration; fault; diagnosis; abnormal vibration

DesignandExperimentof6-DOFMicro-displacementPositioningStage

JIRuinan1,JINJiamei1,ZHANGJianhui1,2

(1. State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics Nanjing, 210016, China)

(2. School of Mechanical and Electric Engineering, Guangzhou University Guangzhou, 510006, China)

AbstractPiezoelectric stacks and flexure mechanisms constitute the fundamental forms of micro-displacement positioning. Its comprehensive structure design includes the contradictions between stroke and output force caused by the application requirements. To satisfy the requirement of six degrees of freedom(6-DOF) micro-displacement for ultra-precision machining tools, we put forward a 6-DOF micro-displacement positioning stage, which is driven by piezoelectric stacks and uses flexure mechanism and wedge mechanism for transmission. In order to obtain high micro-displacement precision and high output force of piezoelectric stacks, a certain level preload is needed. On the basis of the relational expression between driven force and displacement in each degree of freedom and stiffness expression obtained by static analysis, the structure of the stage is optimized. Experiment results show that the maximum displacement inx,y,zdirection is 7.48 μm,8.33 μm, and 4.14μm with the resolution of 0.01 μm; the maximum rotation angle inθx,θy,θzdirection is 0.13° with the resolution of 0.01°. Therefore, this positioning stage meets the requirements for an ultra-precision machining tool, which means piezoelectric stacks and flexure mechanisms can meet the requirements of both stroke and output force through rational design. The relationship curve of driven voltage and output displacement in each direction obtained by experiments provides the basis for movement and positioning control and also offers the theoretical and experimental basis for the application of flexure hinge mechanism and wedge mechanism in other structures.

Keywords6-DOFs; micro-position stage; piezoelectric stack; flexure mechanism; wedge mechanism

ImprovedDeepLearningFusionModelinFaultDiagnosis

WANGYingchen1，DUANXiusheng2

(1. Department of Electronic and Optical Engineering, Army Engineering University of PLA

Shijiazhuang, 050003, China)

(2. School of Mechanical Engineering, Shijiazhuang Tiedao University Shijiazhuang, 050003, China)

AbstractIn light of the problems caused by complex equipment structure, working environment noise, and big data, a deep learning fusion model is proposed to achieve efficient and accurate fault diagnosis. First, the denoising autoencoder is used to process the random noise of the original signal and learn the low-level features. Then, the deep belief network is used to learn the deep features based on the learned low-level features. Finally, the fused depth features are fed into the PSO-SVM to train the intelligent diagnosis model. The proposed method is applied to the fault diagnosis of rolling bearings, The results show that the method proposed is more efficient and robust than the existing methods.

Keywordsfault diagnosis; deep belief network; denoising autoencoder; adaptive learning rate; robustness; support vector machine

AnalysisofSeismicFragilityofAqueductStructureBasedonCopulaFunction

ZHANGJianwei1,2,3,ZHANGShuai1,2,3,ZHANGYina4,HUANGJinlin5,LIZhaoheng5

(1. School of Water Conservancy, North China University of Water Conservancy and Electric Power Zhengzhou, 450046, China)

(2. Collaborative Innovation Center of Water Resources Efficiency and Protection Engineering Zhengzhou, 450046, China)

(3. Henan Provincial Hydraulic Structure Safety Engineering Research Center Zhengzhou, 450046, China)

(4.School of Civil Engineering and Communication，Yellow River Conservancy Technical Institute Kaifeng, 475004, China)

(5.Guangdong Research Institute of Water Resources and Hydropower Guangzhou, 510635, China)

AbstractIt is hard to directly establish the joint probability distribution function of the basic components in the aqueduct system because of the correlation of seismic demand among components in structural vulnerability analysis. A new method for analyzing the vulnerability of the aqueduct structure is proposed. A two-dimensional Copula function is introduced to describe the related structures of component seismic demands and simplify the modeling process of the joint distribution function. First, the vulnerability curves of a bent and rubber bearing are created based on the analysis of time history on a cross of an aqueduct. The independent variable is the peak ground acceleration, and the damage index is the displacement ductility ratio of bent and the deformation of rubber bearing. The uncertainty of ground motion and structural parameters is considered. Second, the vulnerability curve of the aqueduct system is established using the Copula function. Finally, the upper and lower bounds of the aqueduct system vulnerability are obtained by the first-order boundary method. The results show that the failure probability calculated based on the Copula function is between the upper and lower bounds of the first-order boundary method. The results help to simplify the modeling process of the aqueduct system vulnerability curve, and at the same time, providing a new way to study the correlation between seismic demand of aqueduct components.

Keywordsaqueduct; system fragility; Copula function; correlation of seismic; joint probability distribution function

MethodofModelling&FeatureExtractionBasedonComplexNetworkandApplicationinMachineFaultDiagnosis

TIANTian1,WENGuangrui1,2,ZHANGZhifen1,XUBin1

(1.The Research Institute of Diagnosis and Cybernetics, Xi′an Jiaotong University Xi′an, 710049, China)

(2. School of Mechanical Engineering, Xinjiang University Urumqi, 830047, China)

AbstractThe existing complex network methods are directly from the time domain when it is applied in fault diagnosis, which causes frequency domain information of the signal missing, and the extracted topology features of network are too macroscopic, which is not sensitive to network within the local change. Meanwhile, local features usually have more abundant information and represent the network model more accurately than macro features. As a consequence, a new method of local feature extraction based on frequency complex network decomposition is proposed. The method obtains the changing rule of the signal in the frequency domain with the aid of the structural characteristics of complex networks and uses the microscopic features that is sensitive to network within the local change to represent the whole network. It is flexible to apply without limit by the mechanism. Classification experiments on different faults of rolling bears are conducted to compare the proposed feature, existing complex network topology features and statistical parameters in time domain. The experimental result indicates that the proposed feature has well separability and high recognition efficiency, which could satisfy the need of rolling bearing fault diagnosis and also has a reference value for the non-stationary signal processing of other parts in machine.

Keywordsfrequency-domain complex network (FCN) decomposition; sub-network average degree; rotating machine; fault diagnosis

DoubleLayerFloatingRaftVibrationAttenuationSystemforAntarcticSurveyTelescopeTransport

WENHaikun1,2,GONGXuefei1,2,CUIPenghui3,YAOXu3,DUFujia1,2,LIZhengyang1,2

(1. National Astronomical Observatories/Nanjing Institute of Astronomical Optics & Technology, Chinese Academy of Sciences Nanjing, 210042, China)

(2. Key Laboratory of Astronomical Optics & Technology, Chinese Academy of Sciences Nanjing, 210042, China)

(3.Polar Research Institute of China Ministry of Natural Resources of the People′s Republic of China Shanghai, 200136, China)

AbstractDome A is the most remote region from the coast of the Antarctic, but it has a very important scientific value. The vibration and shock acceleration from Shanghai to Dome A is much larger than the ordinary road. The paper proceeds as follow: Firstly, the vibration acceleration from Shanghai to Dome A is introduced, and the largest location range is determined as the focus of the package cushioning design system. Secondly, a double layer floating raft vibration attenuation system is designed, and the parameters of the system is designed according to the vibration environment. Also the statics and dynamics analysis of the system is showed. In the winter of 2013, the actual test of this system has been done in MoHe China. The test results show that the system can meet the transport safety requirements of the telescope mirror.

Keywordsvibration and shock; Antarctic; telescope; floating raft vibration attenuation

NoiseAnalysisandVibrationControlofVibratedParticlesRehabilitationDevice

QUYunxia，WANGShiyang，HOUShujun,LIKai,WANGMengdi

(School of Mechanical Engineering, Hebei University of Technology Tianjin, 300131, China )

AbstractThe vibration and noise control strategy of the new developed particle vibration rehabilitation device is proposed. Firstly, the sound intensity of the prototype is tested, and it is confirmed that the thin-walled cylindrical barrel and particle layer are the main noise sources. Then, by finite element method (FEM), the vibration response of cylindrical barrel are calculated. After that，the frequency response curve of sound pressure level at cylindrical barrel field point is obtained, and the numerical simulation model of cylindrical barrel noise analysis is constructed and conformed by rig experiments. The vibration transmission path of the stainless steel cylinder barrel is improved by replacing the connection of the bottom of the barrel with a flange and rubber layer between the flange and the vibration platform. It is shown by simulation that the sound pressure level at the field point is reduced about 16.7 dB compared with the original prototype. And when the cylinder barrel material is changed to polymethyl methacrylate which is more damping and thicker, the field point sound pressure level will be expected to reduce about 28.2 dB，partly because the increase of the natural frequencies of the structure help to avoid resonance to take place. Finally, a test prototype with a polymethyl methacrylate barrel and a vibration isolation layer is set up. It is shown that the noise is reduced by about 15.2 dB(A) compared with the original prototype; and the noise is reduced about 3.5dB(A) if the barrel is filed with massage particles.

Keywordsvibration noise; noise source; thin-walled cylindrical barrel; vibration isolation

ModalCharacteristicsAnalysisforCarBodyofHigh-SpeedElectricMultipleUnits

WANGPeng1,2,CHENEnli1,HUIMeiling2,CAIDajun3

(1. School of Traffic and Transportation, Shijiazhuang Tiedao University Shijiazhuang, 050043, China)

(2. Production R&D Center, CRRC Tangshan Co., Ltd. Tangshan, 063035, China)

(3. School of Mechanical Engineering, Yanshan University Qinhuangdao, 066000, China)

AbstractThe irregularity of track and the operation of equipment makes high-speed electric multiple units (EMU) to generate complex vibration during operation, which seriously reduces riding comfort and driving safety. In view of these problems, modal analysis is carried out on car body in order to improve the dynamic response of vehicle. A finite element model for the car body of a high-speed EMU is built, three kinds of car body modal under different mass conditions are calculated, the effects of equipment hanging position and hanging point number on modal frequencies of car body analyzed, and the change ranges of modal frequencies and modal shapes are concluded. On the basis of the finite element calculation, the vehicle modal test system is built, the modal tests of the car body is performed, the difference between the simulation results and the test results is analyzed, and the validity of numerical calculation and finite element model is demonstrated. Results show that the modal frequencies of the car body meet design standards, the modal shapes have the similar variation tendency under different mass conditions, hanging position has obvious influence on the modal frequencies of under frame vertical bending and car body torsional bending, and the modal frequencies of car body increases gradually with the increase of hanging point number.

Keywordshigh-speed electric multiple units; car body structure; finite element analysis; modal test; modal frequency

SystemofMicroscaleInjectionBasedonLeadLinearUltrasonicMotor

YANGJianzhi,PENGHanmin,SHENGJuan,ZHUPancheng

(State Key Lab of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics Nanjing, 210016, China)

AbstractIn order to solve the large-sized and low-precision problems of traditional injection pump using stepper motor system, a lead linear ultrasonic motor is utilized as the driving element of this injection system, and the flow velocity can be controlled by adjusting the voltage and duty factor of driving signal. The size of the motor is 4 mm×4 mm×15 mm which satisfies portable requirement and overcomes the large-sized problem. In flow velocity experiments, the voltage and duty factor of driving signal can be used to accurately control the flow speed. Without any speed reducer, the maximum of flow velocity reaches 61.87 μL/s at 300Vp-pand 100% duty factor, and the minimum of flow velocity is 0.01 μL/s at 200Vp-pand 1% duty factor. The injection system can stably work at the minimum flow velocity, and its precision is better than traditional injection pump whose minimum is 0.028 μL/s. Therefore, this control method of injection system with ultrasonic motor can improve the accuracy up to 0.01 μL/s with a small size, and it also has a good output performance.

Keywordsultrasonic motor; injection pump; control of flow velocity; piezoelectric

MagneticGradientResonanceSparseDecompositionandBMSRIdentificationMethodforPipelineDamage

WANGXinhua，QILifu，CHENYingchun，ZHAOYizhen，GAOChengcheng

(College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology Beijing, 100124, China)

AbstractTo extract the magnetic signal generated by a stress concentration of buried steel pipeline geomagnetic environment exactly, and to overcome the drawback of the existing magnetic testing, which lacks effective detection of high sensitivity multiple probe array and signal processing technology, a kind of method using magnetic gradient tensor with resonance sparse decomposition and bias monostable stochastic resonance (BMSR) to evaluate the pipeline damage identification is put forward. Firstly, the probe arrangement is in the form of a cross tensor array. Secondly, according to the characteristics of the pipeline defect and on-site interference signals, the resonance sparse decomposition of the signal with different quality factors is used to eliminate some interference signals. Finally, the stochastic resonance system with different time domain recovery is added with quantum genetic algorithm for parameter optimization. The identification method is used for the actual station pipeline tensor detection signal, compared with the results using the traditional low-pass filtering, stochastic resonance system combined with different resonance sparse decomposition, the magnetic gradient tensor resonance sparse decomposition and bias monostable processing algorithm is verified to be effective on extracting pipeline damage characterization of magnetic field and pipeline stress concentration.

Keywordsmagnetic force detection; gradient tensor; resonance sparse decomposition; stochastic resonance

SeismicPerformanceandSpectralAnalysisofNonlinear-LinearCombinedStructuralControlMethods

WANGJingjing1,LIUZhibin1,LIHaobo2,YUEHongtao2

(1. School of Civil Engineering, Guangzhou University Guangzhou, 510006, China)

(2. College of Civil Engineering, Hunan University of Technology Zhuzhou, 412000, China)

AbstractStructural control technologies that feature both nonlinear mass dampers namely nonlinear energy sinks (NES) and linear mass dampers, namely tuned mass dampers (TMD) are not only effective in reducing structural responses but also robust against loading changes and structural uncertainties. To study the control performance of single-mass dampers (SMD) and dual-mass dampers (DMS)， the responses of various control devices including a SMD, a DMD, an NES, and a TMD are analyzed when they are attached to an eight-degree-of-freedom primary structure, respectively. Those devices are optimized under impulsive excitations and further investigated when subject to seismic excitations. Spectral analysis is conducted to look into the control capacities of control methods with different degree of linearity and nonlinearity. Results show that nonlinear-linear combined methods are of higher performance than TMD and NES against seismic excitations.

Keywordsstructural control; combined method; seismic excitation;spectral analysis; numerical simulation

FaultDiagnosisofRollingBearingUnderVariableLoadConditionBasedonVariableModeDecompositionandMulti-classRelevanceVectorMachine

XUBo1,2,ZHOUFengxing1,LIHuipeng1,2,YANBaokang1,LIUYi2,3,YANDan2

(1. School of Information Science and Engineering, Wuhan University of Science and Technology Wuhan, 430081, China)

(2. School of Electronic Information, Huanggang Normal University Huanggang, 438000, China)

(3. School of Mechanical Science and Engineering, Huazhong University of Science and Technology Wuhan, 430074, China)

AbstractIn order to accurately and effectively diagnose bearing fault and its fault degree under the variable load conditions, variable mode decomposition (VMD) based on improved chaotic fruit fly optimization algorithm and multi-class relevance vector machine (MRVM) based on nested one to one algorithm is proposed. Firstly, the improved chaos fruit fly optimization algorithm(ICFOA) is used to optimize the penalty parameter and component numbers of intrinsic mode function (IMF) of the VMD, and search for the optimal combination of two parameters. Next, the key parameters of VMD are set by using the optimal combination parameter value, and the corresponding IMF components are obtained by decomposing the known fault signals. Then, the nested one-to-one algorithm is used to construct a high-precision multi-classification RVM learning model, and the 2-D marginal spectral entropy of IMF components are used as the input feature vector of MRVM. Finally, the experimental data under different loads are used to verify the results. The experimental results show that the proposed method can accurately diagnose bearing faults under variable load conditions, in which the diagnostic accuracy of bearing fault type is 100%, the diagnostic accuracy of bearing fault degree is 91.87%, and with high accuracy and robustness.

Keywordsvariable mode decomposition(VMD); multi-class relevance vector machine (MRVM); improved chaotic fruit fly optimization algorithm (ICFOA); nested one-against-one; 2-D marginal spectrum entropy; fault diagnosis

NewApproachtoInspectionofDeepHolePeckDrillingQualityUsingImprovedDTW

ZHOUYouhang1,2,LIYong1,2,LIUZhenhai1,2,ZHAOHanyun1,2,LIUHanjiang1,2

(1.School of Mechanical Engineering, Xiangtan University Xiangtan, 411105, China)

(2.Engineering Research Center of Complex Tracks Processing Technology and Equipment of Ministry of Education Xiangtan, 411105, China)

AbstractAiming at the difficulty of efficiency and cost in deep hole quality inspection, a method using vibration signal segmentation and improved dynamic time warping (DTW) is proposed to test deep hole peck drilling quality quickly. Firstly, the vibration signal of peck drilling is segmented by the double window bispectrum algorithm with excellent anti-noise performance. Secondly, features of the sub-signal are extracted after segmentation in the time and frequency domain for dimensionality reduction. Then, there being the unequal length of feature vector caused by sub-signal, an improved DTW is used to perform regular alignment, reduce the time complexity and prevent ill-conditioned regularity. Eventually, the similarity between the sub-signals is represented by the cumulative shortest distance, so as to determine whether the quality of the corresponding hole segment of the sub-signal is abnormal. The simulation and experimental results show that the method can detect the quality of deep hole machining quickly and effectively, and the analysis results of the vibration signal is consistent with the actual physical inspection, which shows the reliability and practicability of the method.

Keywordspecking drilling; vibration signal; abnormal quality; signal segmentation; improved dynamic time warping( DTW)

VibrationandNoiseReductionofBatteryPackinVehicleBasedontheImprovementofTransferPath

HUShenglong1,ZUOShuguang1,LOUYuwan2

(1. Clean Energy Automotive Engineering Center, Tongji University Shanghai, 201804, China)

(2. Ankao Energy Company Limited Suzhou, 215000, China)

AbstractThis paper aims at the reduction of noise derived from the vibration of relay. Firstly, the noise source of the battery pack is found out through the vibroacoustic test, combining the frequency response function with the vibration spectrum characteristics. Secondly, based on the improvement of transfer path of the vibration of relay, a kind of rubber isolation pad with low stiffness is designed to filter the medium and low frequency vibration of relay so as to realize the noise reduction of the battery pack. Finally, the results indicate that the vibration of relay is passed directly to the shell of battery pack by the rigid connected bolt, which results in the vibration of shell and radiated noise. The rubber isolation pad designed in this paper can effectively filter the medium and low frequency vibration of relay to realize the noise reduction. When the upper cover plate is open, the total sound pressure level is reduced by about 6 dB; when the upper cover plate is closed, the total sound pressure level drops nearly 11 dB.

Keywordsbattery pack; relay; vibration; noise; rubber isolation pad

(EndoftheVolume39)