第39卷第3期英文摘要

KeyTechnologiesandDevelopmentTrendofSmartBearing

ZHUYongsheng，ZHANGPan，YUANQianqian，YANKe，HONGJun

(Key Laboratory of Education Ministry for Modern Design & Rotor-Bearing System, Xi′an Jiaotong University Xi′an, 710049, China)

AbstractIntelligent bearing is a bearing unit with self-perception, self-decision and self-regulation functions, and is the main development direction of the high-end bearings. The characteristics of smart bearings are analyzed, and the research progress and development trends of smart bearings are reviewed. It is concluded that the smart bearing technology is still in the primary stage, since the self-diagnosis and self-regulation functions are not mature. It is summarized that the key technologies of smart bearing include sensor technology, self-powered technology and wireless power supply technology, wireless signal transmission technology, intelligent assessment and diagnosis technology and intelligent control technology. Finally, the development trends of systematization, diversification of monitoring information and intellectualization of intelligent bearing are discussed.

Keywordssmart bearing; sensor bearing; condition monitoring; state regulation

ComparativeResearchonWindVibrationCoefficientforCoolingTowers

UndertheInternalandExternalWindPressure

DULingyun1,2,KEShitang1,HOUXian′an3

(1.Department of Civil Engineering, Nanjing University of Aeronautics and Astronautics Nanjing,210016, China) (2.Envision Energy (Jiangsu) Co.,Ltd Shanghai, 200050, China) (3.Department of Civil Engineering Technology, Northwest Electric Power Design Institute of China Power Engineering Consulting Group Xi′an, 710075, China)

AbstractThe study and the value suggestion of wind vibration coefficient are aimed at external wind load in existing specification and literature, which considers the internal wind vibration coefficient is consistent with the external wind vibration coefficient. This method cannot truly reflect the wind vibration effect caused by the internal wind pressure. To contrastively study the wind vibration characteristics and wind vibration coefficient of a super large cooling tower under the internal and external wind load, an under-construction domestic 210 m large cooling tower is set as the research object. Rigid wind tunnel test is conducted to obtain the average and fluctuating wind load inside and outside surface. On this basis, the integrated finite element model of tower cylinder-strut-ring foundation is established. The transient dynamic analysis is used to calculate and analyze the wind vibration response and the coefficient of the super large cooling tower under the internal and external wind load. The standards of wind vibration coefficients under the four typical target responses, the radial displacement, the meridional axial force, the Von Mises stress and the circumferential bending moment, are discussed. The distribution laws of one-dimensional, two-dimensional and three-dimensional internal and external wind-induced vibration coefficients of the super large cooling tower are extracted. In the end, the value suggestion and the two-dimensional fitting formula of wind vibration coefficients are given. The main conclusions can provide a scientific basis for the accurate value of the wind vibration coefficient of this kind of super large cooling towers.

Keywordssuper large cooling tower; wind tunnel test; internal and external wind pressure; wind vibration coefficient; fitting formula

PlanetaryFaultDiagnosisviaDemodulatedSynchrosqueezingRidgeExtraction

WANGXiaojian,TUXiaotong,LIHongguang,LIFucai,BAOWenjie

(State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University Shanghai, 200240, China)

AbstractMatching demodulation is a new method of time-frequency analysis. The paper proposes a matching demodulation and synchrosqueezing technology to extract ridges of frequency from a multi-component-signal spectrum. The ridges of weak energy component signals are obtained by using translation operator filtering and envelope line filtering. By using this method, the fault component can be simultaneously extracted with the component of the fundamental frequency. Simulation and example analyses show that the proposed method is superior to the general ridge extraction method. The method applied to the planet gearbox, can effectively extract the fault characteristic component, and the fundamental frequency.

Keywordschirplet transform； synchrosqueezing transform； curve extraction； non-stationary signal； planetary gearbox fault diagnosis

PredictionandAnalysisoftheVibrationResponseTrendofPumpingStationPipelinebyIVMD

ZHANGJianwei1,2,3，HUAWeiwei1,2,3，HOUGe1,2,3

(1.School of Water Conservancy, North China University of Water Resources 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)

AbstractIn this paper, improved variational mode decomposition (IVMD) and support vector machine(SVM)are combined to predict the vibration response trend of the pipeline. Firstly, the decomposition mode of IVMD is determined by the mutual information criterion, overcoming the shortcoming of VMD which selects the decomposition parameters blindly. IVMD is used to decompose the vibration series of generating units and pipelines into several intrinsic mode functions which are used as the input and output of the SVM prediction model, respectively. Secondly, the optimal parameters of the SVM model corresponding to each modal component are determined by particle swarm optimization (PSO), and each component is predicted separately. Finally, the prediction results of each modal component are reconstructed to obtain the predicted value of the original series. Taking the No.2 pipeline of a pumping station as the research object, the three models of IVMD-SVM, PSO-SVM and BP neural network are adopted to predict the vibration response trend of pipelines, and the prediction results are compared and analyzed. The results show that the predictive value obtained by IVMD-SVM method is closer to the real value; moreover, the error is smaller and the calculation accuracy is higher. This method has certain utilization value for forecasting the vibration trend of pipelines and similar engineering structures.

Keywordsvibration; improved variational modal decomposition; support vector machine; pipeline; prediction

BandgapPropertiesinStubbed-onLocallyResonantPhononicCrystalDoublePanelStructures

QIANDenghui1，SHIZhiyu2,WUJinghong1

(1.College of Civil Engineering, Suzhou University of Science and Technology Suzhou, 215011, China) (2.State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics Nanjing, 210016, China)

AbstractThe stubbed-on locally resonant (LR) phononic crystal double panel structure made of a two-dimensional periodic array of a cylindrical LR pillar connected between the upper and lower plates is constructed, and the bandgap properties of the structure are investigated in detail. The band structures, displacement fields of eigenmodes and transmission power spectrums of the corresponding finite structure are calculated by a finite element method. Numerical results and the further analysis demonstrate that a band gap with a low starting frequency and a wide band width is opened by the coupling between dominant vibrations of the pillars and plate modes, if the vibration source and receiver are considered on different sides of the structure. In addition, the influence of coupling between sound and vibration in the cavity on the band gap can be ignored. Many common characteristics are displayed between the double panel and the corresponding single plate, but the double panel structure has the excellent property of wide band gap. By changing the relevant parameters of the structure, the band gap can be adjusted effectively.

Keywordsbandgap property;phononic crystal double panel structure; band structure; displacement field; transmission power spectrum; sound-vibration coupling

TheSpatialCuttingStabilityofCNCMachineToolBasedonKrigingModel

DENGCongying1,MIAOJianguo2,YANGShanshan2,YINGuofu2,WEIBo1

(1.School of Advanced Manufacture Engineering, Chongqing University of Posts and Telecommunications Chongqing, 400065, China) (2.School of Aeronautics and Astronautics, Sichuan University Chengdu, 610065, China)

AbstractA method to study the machine tool′s spatial cutting stability is proposed based on the Kriging model, for the complex and uncertain prediction of the cutting stability caused by the spatial pose change of machining point. Taking the minimum limit cutting depth as the research object, this method establishes a Kriging model to predict the relationships between the cutting stability and the machining position, revealing the spatial change rule of the minimum limit cutting depth. The improved particle swarm optimization is introduced to calculate the machining position with the optimal minimum limit cutting depth, which is also combined with the cutting experiment and the energy distribution theory to determine the modes easy to chatter and the related weak joints. Then, the joints stiffness is optimized to improve the minimum limit cutting depth further. The proposed cutting stability analysis method has been applied to a time-consuming process of a three-axis vertical machining center. The position changes show great effects on the machining stability, which are combined with the optimization scheme of the joint stiffness to improve the minimal cutting depth effectively.

Keywordscutting stability; minimum limit cutting depth; Kriging model; machining space

ExperimentalStudyonTwo-LinkRigid-FlexibleManipulatorVibrationControl

QIUZhicheng,LICheng

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

AbstractIn order to suppress the vibration of rotating flexible manipulator caused by external disturbance, a rigid-flexible manipulator experimental platform is designed and constructed, with a rigid upper arm and a flexible forearm. Vibration signals are measured by utilizing the piezoelectric ceramic patch pasted at the root surface of the flexible arm, and the manipulator is driven by using an alternating current (AC) serve motor with a reducer. Then, a feed-forward control scheme based on input shaping technology (IST) and a feedback control scheme designed by generalized minimum variance self-tuning controller (GMVSTC) are designed, and the corresponding experiments are conducted. To verify the effectiveness of the control schemes, the capability of the controllers are evaluated in terms of vibration reduction compared with the experimental results under proportion differentiation (PD) control. The experimental results demonstrate that the input shaping and self-tuning controller can largely reduce the vibration time of the flexible arm. Thus, the vibration of the flexible arm can be rapidly suppressed.

Keywordsflexible manipulator; vibration control; input shaping technology; generalized minimum variance self-tuning controller

ImprovementandExperimentalResearchonHigh-SpeedMagneticBlowerandPipelineSystem

DUYi1,2,3,SONGXinda1,2,3，HANBangcheng1,2,3

(1.Science and Technology on Inertial Laboratory, Beihang University Beijing, 100191, China) (2.Novel Inertial Instrument & Navigation Technology Key Laboratory of Fundamental Science for National Defense Beijing, 100191, China) (3.Beijing Engineering Research Center of High-Speed Magnetically Suspended Motor Technology and Application Beijing, 100191, China)

AbstractAiming at that the traditional Greitzer blower model is not appropriate for the object, an improved model of pipeline and outlet pressure is present in which the motor speed is variable. Compared with the original Greitzer model, the improved model considers the inevitable bending pipe in practical applications and the local pressure loss of the elbow. Moreover, the pressure loss along the pipeline which is neglected in the original model is also included. Therefore, the export pressure is more accurately calculated by the improved model. The validity and accuracy of the improved model are verified by comparing the experimental data with the model theory results. Furthermore, the relative errors in the medium and high-pressure output stage are within ± 3% and ± 1%, respectively. In addition, the comparison between the improved model and the model without the pipeline pressure loss is also made. The result shows that the accuracy of the improved model has been improved by ± 1% both in the medium and high-pressure output stage.

Keywordscentrifugal blower；dynamic model；out-let pressure；motor speed control

DegradationPatternMiningofConditionMonitoringDataBasedonHierarchicalClustering

LIUBaibing，SONGDong，LIChunxiao

(Aviation Engineering，Northwestern Polytechnical University Xi′an， 710000， China)

AbstractPrognostics and health management (PHM) technology, in the modern complex equipment, high reliability, and high-security requirements, is a new technology concept to achieve condition-based maintenance. One of the research directions of PHM technology is to use the information contained in the system status monitoring data to evaluate, analyze and forecast the health and development of the equipment. Aiming at the problem of recessive pattern mining based on state monitoring data, a P-D-H clustering method is proposed to realize the mining of degradation pattern. First, the pattern of the degraded trajectory time series formed by the state monitoring data is represented by the piecewise aggregate approximation method. Then, the dynamic time warping distance is used as the similarity measure of the pattern sequence. Finally, the hierarchical clustering method is used to achieve the regression model clustering. In this way, the wear data of the rolling bearing wear condition is excavated and the effectiveness of the method is verified. The model clustering method based on the complex system state monitoring data can effectively realize the mining of the system health degradation pattern. The result of pattern mining can lay a good foundation for the system health forecasting.

Keywordsstatus monitoring data; health degradation; time series; clustering

ModelingMethodforChatterStabilityLobesofBall-EndMillBasedonPreciseIntegration

DAIYuebang,LIHongkun,WEIZhaocheng

(School of Mechanical Engineering, Dalian University of Technology Dalian, 116024, China)

AbstractSince ball-end mill plays an increasing role in machining sculptured surface, it is of great significance to construct the chatter stability lobes for ball-end mill. The precise integration method is proposed in this paper to solve the two order kinetic equation of the milling system considering modal coupling. Based on the condition of the period of delay equal to the single tooth cutting cycle, the instantaneous cutting parts of the cutting edges are determined by the relationship between the contact area and the cutting edge at different time. The Floquet theory is applied to acquire the high precision chatter stability lobes, which are verified by the flat surface machining in the three-axis numerical control (NC) machine tool. The experimental results are in good agreement with the predicted results, indicating the method proposed in this paper can provide the technical support for ball-end milling without chatter.

Keywordsprecise integration; modal coupling; chatter; ball-end mill; stability lobes

LeastSquareAdaptiveTransmissionPowerControlMethodfor

MachineVibrationWirelessSensorNetworks

TANGBaoping,ZHAOChunhua,DENGLei,XIAOXin,HUANGYi

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

AbstractMachine vibration wireless sensor networks node often works at the wireless radio frequency phase where the transmitted energy is the largest to ensure the reliability of transmission, but resulting in a large transmission power consumption of sensor nodes, especially in mass raw data transmission requirements, In the light of this problem, a least squares adaptive transmission power control(LSATPC) method for wireless sensor networks nodes is proposed. First, the discrete relationship between transmission power and link quality indicator (LQI) is studied through inner-cluster sensor nodes communication in the mechanical vibration monitoring in laboratory environment. Then, the least squares method is utilized to fit the discrete data, thus to construct the least squares adaptive transmission power mathematical model for reliable and energy-efficient data transmission. Finally, combined with the threshold value of LQI, the optimal wireless transmission power of the nodes at different communication conditions is calculated, satisfied with the result of the reliable data transmission. Experimental results indicate that the transmission energy consumption of mechanical vibration wireless sensor network nodes can be effectively reduced by this method.

Keywordsmachine vibration monitoring; wireless sensor networks (WSNs); transmission power; adaptive; transmission energy

OptimizedResearchontheBandGapsofThreeDimensionalHoneycombPhononicCrystal

SHAOHanbo，CHENGuoping，HEHuan

(College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics Nanjing, 211100, China)

AbstractHoneycomb phononic crystal has excellent features in reducing noise and vibration. For the crystal with nitrile rubber as the base and steel as the scatterer, a wider frequency band gap and better vibration reduction effect is realized by constructing different honeycomb phononic crystal model and changing the geometric parameters. The model is constructed based on the periodic boundary condition and Bloch theory using COMSOL software. The band structure are calculated and compared with the transport properties. Finally, the most superior honeycomb phononic crystal was found out and a new method to control the band gap was claimed.

Keywordsphononic crystal; adjustable; honeycomb; band gap

StructuralModalSystemIdentificationUsingVariationalModeDecompositionandTeagerEnergyOperators

JINHang，LINJianhui

(State Key Laboratory of Traction Power, Southwest Jiaotong University Chengdu, 610031, China)

AbstractA new structural system identification method based on variational mode decomposition(VMD) and Teager energy operator(TEO) is proposed. The structural modal characteristics are identified based on the pole stability of VMD layer parameterK. In order to satisfy the requirement of TEO for single component, the vibration signal is decomposed into detail signals of different scales by VMD method. For band-limited intrinsic mode function(BIMF), TEO method is used to estimate the natural frequency and damping ratio. By comparing the pole stability of VMD layer parameter K modal characteristic parameter, the false component is removed. The numerical and experimental results show that the proposed method is effective, accurate and feasible in both traditional modal test modal analysis and environmental excitation modal analysis.

Keywordsnatural frequency； structural damping ratio； modal parameter； variational mode decomposition； Teager energy operator

AbnormalSoundTestAnalysisinDoorClosingCasewithFullyDroppedGlassBasedonModalDecomposition

GAOYunkai,SHIWang,YANGZhaotong,WANGGenhai

(School of Automobile, Tongji University Shanghai, 201804, China)

AbstractIn th light of the door closing abnormal sound appears at the glass of the vehicle door in the full drop state, a method based on modal decomposition of operational deflection shape for identifying vibration sources of abnormal sound is proposed. First, time-frequency analysis of the noise signal is carried out through the short time Fourier transfer method. The result shows that the abnormal sound has secondary impacts. The energy of noise is mainly distributed in the low-frequency radiated section. Then, the test of operational deflection shape is used to identify door deformation. The modal frequencies and vibration shapes are obtained by modal test. Finally, the vibration source of the abnormal sound is diagnosed through the result of modal decomposition. According to this method, the main vibration source of the abnormal sound is identified successfully, and some suggestions for improvement are put forward. The improved test result shows that after the optimization, the secondary impacts and abnormal noise disappeared. The experimental result shows that the method is feasible and valid.

Keywordsdoor closing abnormal sound; short time Fourier transfer (STFT); modal decomposition; operational deflection shape (ODS); secondary impact

InfluenceofNozzleHighEfficiencyMuzzleBrakeonFiringPerformanceofGun

XIANDongpeng1,LIAOZhenqiang2,XIAOJunbo2,SONGJie2

(1.School of Mechanical Engineering, Nanjing Institute of Technology Nanjing, 211167, China) (2.School of Mechanical Engineering, Nanjing University of Science and Technology Nanjing, 210094, China)

AbstractBase on the half-open muzzle brake, a nozzle high-efficiency muzzle brake is designed. Draw out the level backwards Laval nozzle on two sides of the half-open muzzle brake, and use the high-pressure gas in chamber to achieve low recoil force, and compute interior ballistic trajectory. Base on the rigid-flexible coupling dynamic theory, the dynamic model of vehicle Gatling gun with nozzle high efficiency muzzle brake are made, and the numerical simulation is computed. The results show that the firing performance of gun system is improved when the recoil force, recoil displacement, muzzle angular displacement and projectile displacement decrease.

Keywordsordnance science and technology; dynamic simulation; muzzle brake; nozzle; high efficiency; firing performance

ResidualVibrationSuppressionbyanIntegratedMethodofParameterIdentificationandInputShaping

LILin,HUXiqin,ZOUYanbiao

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

AbstractSerious residual vibrations are widely and frequently observed when industrial robots are conducting fast motions. Input shaping technology is used to reduce the residual vibration of many systems by generating a command signal that is self-canceling. It is difficult to obtain the modal parameters of the system due to the modeling errors. Thus, the residual vibration are never exactly suppressed on real systems. In the light of these problems, an integrated method of parameter identification and input shaping technology is proposed and a modified input shaping approach is developed, The time delay introduced by conventional input shaping technique is fully compensated in the proposed approach. In order to achieve the precise and rapid rest-to-rest motion, a single degree-of-freedom robot arm is used as an application case. Experimental results show that theproposed method significantly reduces the residual vibrationof the robot arm,the maximum amplitude of residual vibration is only 31% of the original′s. At the same time, the settle time is shortened from 0.118 s to 0.043 s, and the total time of motion control is reduced from 1.738 s to 1.643 s.

Keywordsresidual vibration; input shaping; modal parameters; time delay; settling time

VibrationTransmissionAnalysisofaSemi-activeOne-StageIsolationSystemforMarineEquipment

FANGYuanyuan1,2,ZUOYanyan1,SHAOGuangshen2，XIAZhaowang2

(1. School of Automotive and Traffic Engineering, Jiangsu University Zhenjiang, 212013, China) (2. School of Energy and Power Engineering, Jiangsu University of Science and Technology Zhenjiang, 212003, China)

AbstractTo improve the vibration isolation performance of the one-stage isolation system for marine equipment, the influence of the semi-active magnetorheological (MR) damper and base mass on the vibration transmission of the system is studied. An improved Bingham model verified by experiment is adopted to describe the nonlinear damping force of the MR damper, and the dynamic model of the two degree of freedom unconstrained isolation system considering the influence of the base mass is established. The analytic solution for primary resonance of the isolation system is obtained based on the averaging method which is verified by numerical method. The influence of the main system parameters on primary resonance of the isolation system is studied by taking the force transmissibility as evaluation index. The results show that the increase of base mass can reduce the natural frequency and the isolation effect at the vibration isolation zone. The performance of the isolation system can be improved by increasing the control force and zero force velocity of MR damper. The damping increase of MR damper can improve the isolation effect in the resonance region, but have opposite effect on the vibration isolation region.

Keywordsone-stage vibration isolation; force transmissibility; semi-active; magnetorheological damper; averaging method

On-LineResidualLifePredictionforCylinderBasedonDegradationData

LIFeng1,YUANZhikai1,HEZhenxin1,WANGZhaoqiang2

(1.2ndDepartment, Rocket Force University of Engineering Xi′ an, 710025, China) (2.3ndDepartment, Rocket Force University of Engineering Xi′ an, 710025, China)

AbstractIn the light of the residual life prediction in cylinder reliability, an on-line residual life prediction method of cylinder based on degradation path is proposed. First, a degradation model of cylinder based on Wiener process is constructed and the analytical expression of probability density function of residual life determined by the degradation path is deduced. Then, a parameter estimation method based on Bayesian paradigm and expectation maximization algorithm is proposed to achieve the on-line residual life prediction. Finally, the validity of the proposed residual life prediction method is verified by the cylinder performance degradation experimental data. The results show that the method proposed in this paper can predict the residual life of the cylinder more accurately with a lower prediction uncertainty compared with the existing similar methods in the case of the small sample.

Keywordscylinder; wiener process; Bayesian estimation; residual life

LoadIdentificationModelandMeasurementMethodofLoaderWorkingDevice

WANYipin1，SONGXuding1，YULuping1，YUANZhengwen2

(1.The Key Laboratory of Road Construction Technology and Equipment of MOE, Chang′an University Xi′an, 710061, China) (2.Engineering Machinery Research Institute of Xuzhou Construction Machinery Group Xuzhou, 221004, China)

AbstractThe characteristics of the load and the change of the external load of the loader working device are studied. First, the external load identification model is established according to the relationship between the bucket hinge point force and the bucket tip force. Then, the three direction force pin sensor method and the boom section moment method are proposed. The load verification and dynamic load test of iron ore material are carried out on the prototype of the LW900K loader. The results show that the hinge point force could be gained accurately by these two methods, and the accuracy of the boom section moment test results is lower than that of the pin shaft sensor. Under the test equipment of iron ore material, the load of the working device appears in the time of digging and unloading materials. For the first time, the inertial impact load of LW900K loader is obtained through the test, and the peak load is about 400kN. The relationship between the mean, amplitude and frequency of the resultant force of the working device is obtained by the rain flow counting method. It is found that the distributions of load mean and amplitude obey normal distribution and Weibull distribution with three-parameter respectively. The load identification model could effectively solve the problem of the external load acquisition difficulty of loader working device, and the load time history data could be used as reference for the load spectrum and the analysis of the structural fatigue characteristics.

Keywordsloader; working device; load identification model; load measurement method

AnUltrasonicMotorTestDrivePowerwithWide-RangeRegulatedVoltage

LONGTaoyuan,ZHANGTiemin,LIANGLi,DONGYikui

(Engineering College, South China Agricultural University Guangzhou, 510642, China)

AbstractThe existing method for testing the new ultrasonic motor(USM) is to study the special test drive power supply. In order to avoid the influence of long development cycle and high material and labor cost caused by repetitive development of the drive power, the USM test drive power supply with wide range of voltage regulation is studied. Firstly, the relationship between transformer volume and loss and frequency is analyzed theoretically, and the power supply is determined as a transformer-less structure; then the boost equivalent circuit is analyzed to derive the upper limit of the boost ratio, and the adjustment of the duty cycle of the inverter circuit will lead to an increase in total harmonic distortion (THD). In summary, the test drive power supply topology is controlled by a controlled rectifier + boost circuit + half-bridge inverter three-stage circuit; a pre-configuration + automatic selective control strategy is proposed to solve the stability problem of cascade circuits. The test results prove that the test drive power can output 2 phase operating frequency of 10～100 kHz, phase difference within ±90°, and voltage amplitude of 20～600 V AC. Using TRUM60 and linear USM as the load, the test results prove that the test drive power supply can provide suitable drive signals and matching parameters for different USM, and the USM runs smoothly.

Keywordsultrasonic motor(USM)； wide-range regulated voltage； drive power；transformer-less inverter；selective control

PredictionofTrackIrregularitiesbytheARIMAModelofAlignedTrackData

ZHUHongtao1，CHENPinbang1，WEIHui2，LIANGHenghui3

(1.College of Mechanical and Electrical Engineering, Nanchang University Nanchang, 330031, China) (2.College of Automotive Engineering, Jiangxi University of Technology Nanchang, 330098,China) (3.Guangzhou Railway Group, Huizhou Railway Section Huizhou, 516000, China)

AbstractTrack geometry data is obtained by checking the measured track, however, the performance of historical data from different time is often accompanied by the existence of cumulative mileage errors due to changes in inspection environment and conditions, it will lead to a phenomenon of data that cannot be aligned, then it is impossible to predict the development of track irregularities accurately; It is proposed that the multiple sets of raw data should be verified in subsection at a certain step, cross correlation function is used to evaluate each other, the effective observations are obtained after each group's raw data is aligned; then, the historical data in Guangzhou Railway Group Huizhou Railway Section Hangzhou-Shenzhen Line Chaoshan Railway Station No.4 Road K1317+150—K1317+350 between 2013—2015 as the test sample is used to predict the track irregularities by building the ARIMA model. The result shows: research on the prediction of track irregularity after the raw data of track geometry size has been aligned that can achieve higher test accuracy, the maximum relative error is less than 5%, the average relative error is 1.75% in the sample.

Keywordsprediction; track irregularity; auto-regressive integrated moving average (ARIMA)model ; cumulative mileage error; alignment; cross correlation function

GasPathFaultDiagnosisforAero-engineBasedonImprovedDenoisingAutoencoder

HONGJiyu，WANGHuawei，CHEChangchang，NIXiaomei

(College of Civil Aviation, Nanjing University of Aeronautics and Astronautics Nanjing, 210016, China)

AbstractConsidering the state parameters significant nonlinearity and the vulnerability to noise pollution in the aero-engine gas path faults，a method based on denoising autoencoder (DAE) and integrated with a neural networks of firefly algorithm (FA) and radial basis function (RBF) is proposed to diagnose the gas path faults and improve the diagnostic accuracy. The DAE is adopted through greedy algorithms to identify deeper robust features that helps diagnose the faults. To further improve the diagnostic accuracy of the algorithm, inertia weight and improved FA of self-adaptive light intensity factor are introduced to obtain the firefly radial basis function (FRBF) network after optimizing the RBF network. Then the robust features extracted from the DAE are imported into the FRBF for faults diagnosis. Based on practices, the extracting method is compared with the algorithms which are original DAE, independent FRBF, SVM and RBF. According to the results, the proposed method presents highest diagnostic accuracy of 98.1%, stable performance in the algorithms and more satisfying robustness.

Keywordsaero engine； fault diagnosis； denoising autoencoder； firefly algorithm； radial basis function network

EffectSpatialofRoadRoughnessExcitationonVehicle-BridgeCouplingRandomVibration

GUIShuirong1,CHENShuisheng1,WANShui2

(1.Department of Civil Engineering and Architecture, East China Jiaotong University Nanchang, 330013, China) (2. School of Transportation, Southeast University Nanjing, 210096, China)

AbstractBased on road irregularity power spectrum of GB/T 7031—2005, the vehicle-bridge coupling vibration model with multipoint coherent stimulus input is proposed for analyzing the effect of spatial road roughness spectrum on vehicle-bridge coupling vibration. Taking the phase-lag and coherent mul-excitation into condition, a new 3D coherent excitation random vibration model for vehicle-bridge systems is proposed with pseudo excitation method(PEM). In the model, the bridge is modeled as beam-shell solid elements, the vehicle with three axles is simplied as 3D nine-degrees of freedom (DOF) model. Taking the highway beam bridge with three spans as reasearch background, the coherent effect, phased-lag effect and consistent stimulus effect on the vibration response and spectrum characteristic of vehicle-bridge coupling system have been researched. The research demonstrates results as follow. The differences of the bridge displacement and acceleration caused by three spatial road irregularity excitation input are more obvious. The spatial road roughness spectrum has more obvious effects on the responses of car body than rear suspension. There has weak effect on the resonance frequency between vehicle-bridge coupling and road roughness spectrum. The spatial effect of road irregularity stimulus input in researching bridge-vehicle coupling should be taken into account.

Keywordsvehicle-bridge coupling system; road roughness spectrum; spatial effect; pseudo excitation method

Time-VaryingNonlinearParametricIdentificationofIsolatedStructureBasedonWaveletMultiresolutionAnslysis

ZHAOLijie1,LINDongqin1,DUYongfeng2,LIWanrun2

(1.School of Civil Engineering, Hebei University of Engineering Handan, 056038, China) (2.Institute of Earthquake Protection and Disaster Mitigation, Lanzhou University of Technology Lanzhou, 730050, China)

AbstractIn order to study the time-varying nonlinear mechanical behavior of isolated structures under earthquake action, a novel method of identifying time-varying nonlinear parameters of isolated structures is proposed based on wavelet multi-resolution analysis (WMRA) theory. The classic hysteresis nonlinear Bouc-wen model used to describe isolation bearings is studied. In the motion equation established, the three-order effective numerical difference technique is cited to linearize increment expression of restoring force in nonlinear model and form a recursive observation equation. The time-varying parameters to be identified in observation equation are expressed approximately using WMRA, and their identification can be transformed into time-invariant wavelet reconstruction coefficient estimation in multivariable linear regression model. Numerical simulation and shaking table test data of serial seismic isolation system (SIS) are employed to identify evolution law with time of structural parameters and isolation layer parameters, and correctness and applicability of the method are verified. It can be used to evaluate mechanical states of the isolated structures during both construction period and operation period.

Keywordsseismic isolation structures ; time-varying nonlinear; wavelet multi-resolution; hysteresis nonlinearity model; parameter identification

EvaluationMethodofBearingHealthStateBasedonSimilarityofPrincipalCurve

YINAijun1,LIANGZixiao1,ZHANGBo2,WANGDonglei3

(1.State Key Laboratory of Mechanical Transmissions, Chongqing University Chongqing, 400044, China) (2.Southwest Oil and Gasfield Company-Chongqing Gas District Chongqing, 400021, China) (3.Institute of Chemical Materials, China Academy of Engineering Physics Chengdu, 621900, China)

AbstractIn order to more effectively assess bearing performance degradation degree, a rolling bearing state evaluation method is proposed based on the similarity of the main manifold space curve. The high dimensional feature of vibration signal is extracted and then is converted to low dimensional space using the manifold learning algorithm of Laplacian eigenmaps (LE). Then samples from the curve according to soft-Kprincipal curve algorithm are combined with the discrete Frechet distance to plot the condition assessment curve. Comparing with the hidden Markov model (HMM), deep belief network (DBN) method，small breakdown of equipment could be detected earlier，and the health state quantitative assessment of a rolling bearing is achieved.

Keywordsstate evaluation； rolling bearing； principal curves； discrete Frechet distance； degree of performance degradation

EddyCurrentTestingofDirectionalityinAnisotropicCarbonFiberReinforcedPolymerComposite

XUShuai1,CHENGJun1,YANGJiquan1,LIUYijian1,QIUJinhao2

(1.Jiangsu Key Laboratory of 3D Printing Equipment and Manufacturing, Nanjing Normal University Nanjing, 210023, China) (2.State Key Laboratory of Mechanical Structural Mechanics and Control, Nanjing University of Aeronautics and Astronautics Nanjing, 210016, China)

AbstractAccording to the laminated structure and the electrical anisotropy of carbon fiber reinforced polymer (CFRP) composite, an finite element method based on theA-Φ(magnetic vector potential-electrical scalar potential) is proposed to effectively deal with the calculation of eddy currents in CFRP. The numerical method is implemented with COMSOL multiphysics software and the simulation model of anisotropic CFRP laminate is established. The distribution of eddy current density in the plane and thickness directions, and the eddy current distortion caused by the crack defects in the composites are obtained through simulation. Furthermore, the influence of the fiber orientation, crack defect and exciting current frequency on the amplitude and phase of eddy current coil impedance is analyzed based on the impedance method, which is verified by experiment tests. It can be seen from the results that the larger crack defect and the higher frequency lead to the larger coil impedance change and the better detection efficiency. Meanwhile, it can be also seen that the detection effect of orthogonally composite laminate is significantly better than unidirectional composite plate.

Keywordseddy current testing； carbon fiber reinforced polymer (CFRP)； finite element analysis； electrical anisotropy； COMSOL software

PileDefectsDetectionBasedontheChangeofPhaseAngle

LIUJingliang1,ZHENGJinyang1,LINShangshun2,HUANGHao3,CHENXin1

(1.School of Transportation and Civil Engineering, Fujian Agriculture and Forestry University Fuzhou, 350002, China) (2.School of Civil Engineering, Fujian University of Technology Fuzhou, 350118, China) (3.Fujian Research Institute of Communications Science and Technology Fuzhou, 350004, China)

AbstractSince traditional low strain reflected wave method is essentially empirical, a misleading estimation of the damage location of pile foundations may be made. To address this issue, an improved method based on the change of phase angle is presented to detect the position where effects occur. Firstly, the analytical modal decomposition and recursive Hilbert transform are combined to extract the FM parts in a specific region of interest. Secondly, continues wavelet transform is performed on the extracted FM parts to acquire the phase angle and thus the damage is identified according to the varying of the phase angle. Finally, the measured data of the pile of Wangqian #1 Bridge is used to verify the effectiveness and accuracy of the proposed method, and the results demonstrate that the proposed method can preliminarily detect the damage location of the pile and thus facilitate the following damage confirmation, but it still needs more extra proofs based on other damage detection methods or engineering data.

Keywordscontinuous wavelet transform; damage detection; pile foundation; phase angle; time-frequency

DetectionandLocationofSmallCrackUsingNonlinearLaserUltrasonic

LIUYongqiang1,YANGShixi1,GANChunbiao1,WANHaibo2

(1.State Key Lab of Fluid Power Transmission and Control, Zhejiang University Hangzhou, 310027, China) (2.College of Mechanical and Automotive Engineering, Zhejiang University of Water Resources and Electric Power Hangzhou, 310018, China)

AbstractThe produce of small surface and inner cracks is inevitable in metallic structural that is subjected to complex and cyclic loading. The growth of the crack threatens the safety of structure, and may results in serious consequences. It is very important to detect the presence of cracks by non-destructive testing. In this paper, a novel technique for detection and location of small cracks is presented. The metallic structural is radiated by lasers to produce ultrasonic and the state space predictive model is constructed based on the dynamical responses in time domain. A nonlinear damage feature is then extracted from the model to indentify the crack. Furthermore, the crack is located and visualized by using the feature extracted from the entire scanned area. An example of the technique and experimental detection are given for alloys with different cracks. The experimental results show the reliability of the technique.

Keywordslaser-generated ultrasonic; nonlinear waves; crack detection; crack location

MethodofDynamicLifePredictionofRollingBearing

MENGWenjun1，ZHANGSicong1，DANZiyan1，JIANGDuan1，LIUDan1，XUGuanghua1,2

(1.School of Mechanical Engineering， Xi′an Jiaotong University Xi′an, 710049, China) (2.State Key Laboratory for Manufacturing Systems Engineering，Xi′an Jiaotong University Xi′an, 710054, China)

AbstractResearch of the reliability evaluation and life prediction technology is of great significance to preventing faults and supporting predictive maintenance during rolling bearing running. The traditional reliability analysis methods with a static model based on large numbers of failure date and empirical knowledge are unable to track the degradation process of rolling bearing and accurate reliability assessment and life prediction. In this thesis, the dynamic reliability analysis model is established based on the principal component analysis (PCA) and phase space reconstruction. The real-time monitoring parameters are fused through PCA, and then the predictive value of life is obtained by comparing the current degradation process with the historical degradation process. With the continuous accumulation of observed samples, the life of rolling bearing can be updated. The experimental result shows that the dynamic life prediction model proposed in this paper can predict the life of the rolling bearing in real time.

Keywordsprincipal component analysis(PCA)； phase space reconstruction； rolling bearing； performance index； life prediction

Micro-vibrationExperimentandAnalysisonCharacteristicofSatellitePayloadIsolationDevice

LUOJie,TANLimeng,LUOMin,YINXinzhe

(Beijing Institute of Spacecraft System Engineering, Mechanical System Business Department Beijing, 100094, China)

AbstractPayload isolation device is a new design structure of high precision and high stability, which is adapting for the high resolution satellite optical payload with high precision and high stability working environment. It is an urgent problem to be solved that how to validate its characteristic effectively by ground test and quantitatively evaluate its vibration isolation effect. In order to test the modal characteristic and transmissibility characteristic of payload isolation device, a set of micro-vibration experiment system is designed and built, through which effective test data can be obtained. Through comparison and analysis, the vibration isolation effect of payload isolation device is quantified. The experimental investigation result provides important basic data and valuable engineering experience for the development of payload isolation device, and provides a wide range of reference value for the vibration isolation system design of satellite.

Keywordspayload isolation device; vibration isolation effect; micro-vibration; modal characteristic; transmissibility characteristic