第36 卷第1 期英文摘要

第36 卷第1 期英文摘要

Robust Wavelet Transform-Based Kurtogram for the

Fault Diagnostics of Rolling Element Bearing

PengChang1,2,BoLin2,LiuXiaofeng2

(1.Engineering Research Center, CRRC Qingdao Sifang Co., Ltd Qingdao, 266111, China)

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

Abstract Due to the use of the spectral kurtosis based on the fourth sample moments, the Wavelet packet transform filter based method might suffer from the non-robustness problem in practical application. Therefore, robust spectral kurtosis coefficients are defined firstly. Subsequently, the robust Kurtogram based on wavelet packet transform is proposed. The practical data have been applied to demonstrate that the improved method not only can measure the real spectral kurtosis, but also can precisely detect the fault transient components used for the bearing fault diagnosis.

Keywords rolling element bearing; wavelet packet transform; kurtogram; robustness; spectral kurtosis

Study on Dynamic Characteristics of Cartridge Valve in a Vibration Environment

YangZhongjiong1,2,ZhouZhenfeng2,ZhouLiqiang1,2

(1.State Key Laboratory of High Performance and Complex Manufacturing, Central South University

Changsha, 410083, China)

(2.College of Mechanical and Electrical Engineering, Central South University Changsha, 410083, China)

Abstract In order to investigate the influence of a strong vibration environment on the working performance of two way cartridge valves, the structure model and simulation model of the cartridge valve in a vibration environment are established using AMESim software. Influence laws of the vibration condition and the structural parameters of the cartridge valve to its dynamic characteristics are also analyzed separately. The results show that foundation vibrations can cause the cartridge valve flow and open height to fluctuate. The degree of fluctuation of the open height in the steady state increases linearly with the amplitude of the foundation vibration, and is significant when the vibration frequency is over 20Hz. Furthermore, a smaller damping hole diameter can increase the time of the flow raise to the maximum, but the hydraulic oil flow through the valve will be smoother; the fluctuation degree of the open height increases correspondingly with spool quality when the cartridge valve is in the opening state; changing the cartridge valve area can reduce the flow fluctuation; and finally, increasing spring stiffness can also reduce the flow fluctuation, but reduce the flow through the valve.

Keywords fundamental vibration; cartridge valve; dynamic characteristics; vibration condition; structural parameters

Time-Frequency Feature Extraction Method Based on

CSLBP for Bearing Signals

ZhangYunqiang,ZhangPeilin,WuDinghai,LiBing

(Department of Vehicle and Electrical Engineering, Ordnance Engineering College Shijiazhuang, 050003, China)

Abstract A time-frequency feature extraction method based on center-symmetric local binary pattern (CSLBP) is proposed for vibration acceleration signals of rolling bearings. First, the generalized S transform is employed to process vibration acceleration signals of rolling bearings. Two-dimensional time-frequency images with good resolution performance of the bearing signals are obtained by utilizing the time-frequency aggregation measurement criterion to adaptively set the adjustment parameter of the generalized S transform. Then, the CSLBP of the images is calculated. Texture spectra of CSLBP are extracted and utilized to describe time-frequency characteristics of the vibration acceleration signals of rolling bearings. Vibration acceleration signals from four different rolling bearing states are studied. The experimental results indicate that the texture spectrum of CSLBP can effectively express the time-frequency characteristics of the vibration acceleration signals of rolling bearings. It has low dimensional feature and satisfactory separability compared with the texture spectra of local binary pattern (LBP) and uniform pattern LBP.

Keywords rolling bearing; time-frequency analysis; feature extraction; center-symmetric local binary pattern(CSLBP); generalized S transform

Active Vibration Control with a New Online Secondary

Path Modeling Method

PuYuxue,ZhangFang,JiangJinhui,XuJing,JiangQi

(State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of

Aeronautics and Astronautics Nanjing, 210016, China)

Abstract An online secondary path identification method is proposed based on the modified filtered-X least mean square (FXLMS) algorithm, which is applied in adaptive active control of structural vibration. The proposed algorithm can eliminate the perturbation between the active control process and secondary path modeling process, accelerate the convergence speed of the system, reduce the contribution of auxiliary noise to the residual vibration, and simplify the complexity of the algorithm. Active vibration control simulations are provided based on LABVIEW software. Compared with existing methods, the proposed method has superior performance in the convergence and effect of active vibration control. Finally, an active structural vibration control experiment is made on a simply supported beam using the proposed method to achieve good inhibitory effect of the beam′s vibration response. The results illustrate the effectiveness of the secondary path online modeling method for active control.

Keywords active vibration control; online secondary path modeling; adaptive filter; filtered-X least mean square (FXLMS)

An Approach to Extract Inductive Debris Sensor Weak Signal

ZhengChangsong1,2，LiMeng1，GaoZhen1,ChenTuo1

(1.School of Mechanical Engineering, Beijing Institute of Technology Beijing, 100081,China)

(2.Collaborative Innovation Center of Electric Vehicles in Beijing Beijing, 100081, China)

Abstract When a high-frequency alternating current is used to stimulate a three-coil inductive wear particle sensor when wear debris is passing by, a weak inductive electromotive force signal will be produced. Due to the effect of mutual inductance, the inductive coil produces a mutual inductive electromotive force, which brings in high levels of interference. An approach to eliminating this interference and extracting a high signal-to-noise ratio inductive electromotive force signal is of great significance in particle recognition, particle counting and fault estimation. The mathematical model of the sensor using the mutual inductance principle and the concept of wear inductive electromotive force is introduced. Then, the model of wear electromotive force extraction method is established based on the lock-in amplifier principle. Finally, the simulation and the experimental results validate the correctness of the model when the electromotive force signals are successfully separated, and provide the reference for the type of sensor design.

Keywords fault diagnosis; inductive wear particle sensor ;wear inductive electromotive force; signal extraction

Study on the Discreteness of Damping Ratio Identified from

Operational Modal Analysis of Bridge Structure

QinShiqiang1, 2,KangJuntao2，KongFan2

(1. Hubei Key Laboratory of Roadway Bridge and Structure Engineering, Wuhan University of Technology Wuhan, 430070, China)

(2. School of Civil Engineering and Architecture, Wuhan University of Technology Wuhan, 430070, China)

Abstract The precise identification of the damping ratio of a bridge structure is generally challenging. The existing representative damping ratio identification methods in the frequency domain, time domain and time-frequency analysis are summarized in order to study the discrete problem of identifying damping ratios using operational modal analysis (OMA). Reasons for incorrect results in each method are investigated. Then, the identified damping ratios are analyzed by using the OMA of a continuous pre-stressed concrete bridge as an example. Finally, a method to reduce the discreteness of the identified damping ratios is studied. The results show that the damping ratios have higher dispersion than that of the natural frequencies. This problem can be relieved by increasing the sampling time when combining the free vibration response, so the accuracy of the damping ratios would improve. The damping ratios extracted from the ambient vibration responses with lower vibration levels show lower discreteness.

Keywords damping ratio; modal parameter; half-power bandwidth method; stochastic subspace identification; free vibration response

Optimization of Piezoelectric Actuators/Sensors Placement

Using Synthetic ModalH2Norm

LouJunqiang1,WeiYanding2,YangYiling2,XieFengran2,ZhaoXiaowei2

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

(2.Key Laboratory of Advanced Manufacturing Technology of Zhejiang Province, Zhejiang University Hangzhou, 310027, China)

Abstract In active vibration control of a smart flexible structure, the placement of actuators and sensors is a key aspect of the control system design. The optimal placement of piezoelectric actuators and sensors using modalH2norm criteria is considered. Based on Rayleigh-Ritz and modal theory, the system modal equations and closed-loop state space equations are derived. Then, a synthetic modalH2norm criterion representing the controllability and observability of the system is proposed. Using an improved genetic algorithm, the optimal configurations of collocated piezoelectric actuators and stress sensors of the system for single and synthetic modals are found. To verify the validity and feasibility of the presented optimal criterion and method, an experimental system is designed and set up. The analytical and experimental results demonstrate that the smart flexible beam system has a high degree of controllability and observability, such that both the single modal of interest and synthetic modals are well observed and controlled. The proposed optimal criterion and method are feasible and effective.

Keywords smart flexible structure; synthetic modalH2norm; optimal placement; piezoelectric actuators/sensors; improved genetic algorithm

Research on Oil-Film Instability Law of a Rotor Systemduring

Run-Up and Run-Down Processes

MaHui,WangXueling,NiuHeqiang,LiHui

(School of Mechanical Engineering & Automation, Northeastern University Shenyang, 110819, China)

Abstract The finite element model (FEM) of an overhung rotor-bearing system is established. Oil-film instability features and the effect of angular accelerations on oil-film instability laws are analyzed during run-up and run-down processes by the time-domain waveform, spectrum cascade and amplitude-frequency response. The results show that the onset of oil-film instability changes due to the tangential inertia force from run-up and run-down processes, and the instability speeds under the run-up and run-down conditions will be delayed compared with that under stable conditions (with no angular acceleration). Moreover, the second mode instability speed increases slightly as angular acceleration increases in run-up conditions, and decreases slightly in run-down conditions. The phenomenon of hysteresis under run-down conditions can be observed compared with the run-up condition.

Keywords run-up and run-down; rotor-bearing system; sliding bearing; oil whip; finite element

Study on Influencing Factors of Nonlinear Failure Model Test on Shaking Table

LiJing,ChenJianyun,XuQiang,ZhengYi

(Faculty of Infrastructure Engineering, Dalian University of Technology Dalian, 116024, China)

Abstract The seismic loading scheme and constitutive model of emulation material are studied for the dynamic failure model test, and the differences between the damage induced by complete loading and the cumulative damage by step loading are discussed. Examples of a frame structure and a hydraulic concrete structure are used to clarify the damage developing mechanism. The results show that the step loading scheme, similarity of the module, and emulation strength can meet the requirements for the dynamic failure model tests to obtain dynamic characteristics and earthquake acceleration amplitudes that correspond respectively to the damage initiation and ultimate failure, but cannot capture the developing process of failure patterns of the mass concrete structure by a shaking model test. Thus, it is acceptable to adopt some simplified measures according to the test objectives when carrying out a shaking model test.

Keywords model test; structure damage; earthquake; numerical simulation; shaking table

Research of 2-D Holospectrum Calculation Based on HWPT-ZFFT Method

LiJiyong1,LiShunming1,ChenXiaohong2,WangYong1

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

(2. College of Science, Nanjing University of Aeronautics and Astronautics Nanjing, 210016, China)

Abstract A HWPT-ZFFT (harmonic wavelet packet transform and zoom fast Fourier transform) method is proposed for spectrum zoom, targeted for a spectrum that contains three or more intense frequency components. When the signals are orthogonally decomposed into different frequency bands with no redundancy or leakage, they perform better using the box-like spectrum instead of the tradition low-pass and band-pass filter in complex modulation ZFFT. First, the HWPT method is employed to filter the intense components, shift the center frequency to zero, and resample. Then, the frequency, amplitude and phase after zoom are obtained by FFT in order to calculate the holospectrum. Finally, rich fault characteristics are obtained under higher frequency. The effectiveness of this method is demonstrated through simulation and multi-span rotor system experimental results.

Keywords harmonic wavelet packets; intensive spectrum; spectrum zoom; holospectrum

Influence of Braking Parameters on the Stability of Braking System

LiXiaopeng,YueBing,WangDan,WenBangchun

(School of Mechanical Engineering & Automation, Northeastern University Shenyang, 110819, China)

Abstract A braking system consisting of brake discs and friction plates is studied. The kinetic model is established based on the Stribeck friction model. The impact of the initial velocity, brake pressure, damping and stiffness on braking stability is studied by numerical simulation. Then, methods to improve braking stability are proposed. The results show that the vibration amplitude increases with increasing initial velocity, but less time is needed for the system to reach stability. The vibration amplitude decreases with increasing braking pressure. Vibration amplitude can be reduced by appropriately increasing the pressure. The greater the damping, the faster the system reaches stability. The greater the stiffness, the slower the system reaches stability. The vibration amplitude decreases with increasing stiffness before the system reaches a steady state.

Keywords braking system; kinetic model; brake parameters; numerical simulation; system stability

Study on the Quantitative Detection Method of Misalignment

Faults for Rotating Machinery

ZhangXining,NiuDonghui,LiBing

(State Key Laboratory for Manufacturing Systems Engineering, Xi′an Jiaotong University Xi′an, 710049, China)

Abstract Two new simplified quantitative detection methods for misalignment faults are proposed based on the eddy current sensor. A simplified series method based on Fourier series to estimate amplitude and phase is introduced to obtain the amounts of parallel and angular misalignment. Another method based on two points measurement is also proposed to achieve more rapid estimation of misalignment. The principles of measurement and calculation of the two methods are explained, and their performance and effectiveness are verified by simulation and experiments. Experimental results show that the simplified series method can quantitatively detect the misalignment faults of rotating machinery, and the two points measurement method has great practical significance in the rapid estimation of misalignment.

Keywords misalignment faults; quantitative detection; rotating machine; eddy current sensor

Identification for Time-Varying Nonlinear Properties of

Rubber-Bearings in Base-Isolated Buildings

DuYongfeng1,2,ZhaoLijie2,LiWanrun1,2,TangShaoyu2

(1. Western Engineering Research Center of Disaster Mitigation in Civil Engineering of Ministry of

Education Lanzhou, 730050, China)

(2.Institute of Earthquake Protection and Disaster Mitigation, Lanzhou University of Technology Lanzhou, 730050, China)

Abstract To understand the performance state of rubber bearings under seismic action, a new method is proposed to identify time-varying nonlinear properties of the rubber-bearing isolated system based on wavelet multi-resolution analysis technique. First, based on the discrete sequences of wavelet multi-resolution analysis theory, the approximate unknown time-varying nonlinear restoring force of rubber bearings is expressed by the Daubechies wavelet coefficient. Then, the wavelet coefficients are estimated by the least-squares technique, and the nonlinear restoring force of the rubber bearing is reconstructed. Finally, the identification method has been applied to numerical examples. The results show that the proposed approach can accurately identify the nonlinear characteristics of rubber bearings when the superstructure stiffness changes and can also track the stiffness degradation of the superstructure, thus demonstrating its validity and accuracy.

Keywords base-isolated structure; wavelet multi-resolution analysis; time-varying stiffness; nonlinear; rubber bearings

Mechanical Fault Diagnosis Method Based on Multi-level Fusion in

Wireless Sensor Networks

TangBaoping1,2,DengBing2,DengLei2,YanBingsheng1

(1. School of Mechanical & Electrical Engineering, Henan University of Technology Zhengzhou, 450007, China)

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

Abstract Considering the inability of wireless sensor networks (WSNs) to meet the real-time transmission of a large number of vibration signals when applied to mechanical fault diagnosis, a mechanical fault diagnosis method based on multi-level hierarchical information fusion in WSNs is proposed. A cluster tree network structure is used to enlarge the coverage of network monitoring. The information fusion in WSNs is divided into three levels: data level fusion, feature level fusion and decision level fusion. Characteristic information of the raw vibration signals is extracted by terminal nodes for data level fusion. This information is then processed by cluster head nodes to obtain pattern recognition results for feature level fusion. The results are processed by the gateway to assess the mechanical equipment operational condition for decision level fusion. This experiment shows that this method can be applied well in mechanical fault diagnosis.

Keywords mechanical fault diagnosis; wireless sensor networks(WSNs); information fusion; embedded signal processing

Failure Mode Effect Criticality Analysis for Traction Power Supply

System of Electric Multiple Unit

LuBihong,ZhangBinghai,QuBaozhang

(School of Mechanical Engineering, Dalian Jiaotong University Dalian, 116028, China)

Abstract The fault model effect and criticality for the traction power supply system of the electric multiple unit (EMU) is studied to improve the reliability of both the traction power supply system and the high-speed train operation. The fault model effect and criticality analysis (FMECA) method is adopted, the reliability block diagram of the EMU traction power supply system is put forward, and 16 kinds of failures of the traction power supply system are studied. The traction power supply system hazard matrix is obtained from the two dimensions of failure probability and impact severity. Through analysis of this matrix, four important failures are identified that have the highest hazard degree: malfunction of the IGBT monitor module, trip off of transformer oil pump 34-F55, failure of the refrigeration fan, and failure of transformer oil flow. Meanwhile, some corresponding correcting actions are adopted. Feedback results show that the above measures ensure the operational reliability of the traction power supply system. The research outcome also provides useful support for other EMU subsystems in failure analysis, maintenance decision-making and life-management as well.

Keywords traction power supply system; fault model effect and criticality analysis (FMECA); hazard matrix; electric multiple unit (EMU)

Reliability Sensitivity Analysis of Inter-Story Isolation System

ZhangShangrong1,3,TanPing2,DuYongfeng1,ZhouFulin2,BaoChao1

(1.Institute of Earthquake Protection and Disaster Mitigation, Lanzhou University of Technology Lanzhou, 730050, China)

(2. Earthquake Engineering Research and Test Center, Guangzhou University Guangzhou, 510405, China)

(3. School of Civil and Hydraulic Engineering, Ningxia University Yinchuan, 750000, China)

Abstract Considering the uncertainties of the stochastic parameters of an inter-story isolation system and seismic excitation, the implicit structural response function is transformed into an explicit one by SRSM (Stochastic Response Surface Method), combined with the probabilistic collocation method based on the linear independence principle. Then, the reliability and sensitivity of the structure are analyzed using the Monte-Carlo. The results show that the change of each stochastic variant average has different effects on system reliability, which is reduced as the variance of each variant increases. Optimizing design variables and controlling construction quality are important in reducing their impact on the system′s reliability. The analysis results of the reliability sensitivity can provide system reliability indexes to rank stochastic parameters by importance, in order to improve the efficiency of the large-scale complex structure reliability analysis and optimization design. The results also lay the foundation for further study of the reliability sensitivity of the inter-story isolation system.

Keywords inter-story isolation system; stochastic response surface method (SRSM); linearly independent probabilistic collocation; first-excursion failure; reliability sensitivity

Research on the Identification of Axis Orbit in Hydro-generator Unit Base on

PSO-BP and Combined Moment Invariants

ChenXiyang,YanHaiqiao,SunJianping

(School of Energy of Power and Engineering, Huazhong University of Science and Technology Wuhan, 430074, China)

Abstract A new combined moment invariants is proposed to describe the features of a hydro-generator unit′s axis orbit based on Hu moment invariants and affine moment invariants and also act as the input characteristics of back propagation (BP) neural network. In order to overcome the problems of a slow convergence rate and a tendency to fall into a local minimum in the BP neural network algorithm, improved particle swarm optimization (PSO) is applied to train the weights of the BP neural network, so that the BP has enhanced convergence and precision. Quantitative feature parameters of the axis orbit shapes are solved with the optimization method to help operation personnel provide guidelines for the fault location of a hydro-generator unit. The experimental simulation and application results show that the axis orbit identification method with combined moments is better than that by the Hu moment invariants or affine moment invariants individually. The improved PSO-BP method has a faster rate of convergence and higher recognition precision than the classical BP during the identification of the axis orbit. The proposed method of axis orbit identification has been successfully applied to the imbalanced fault diagnosis of the hydro-generator unit.

Keywords combined moment invariants; particle swarm optimization; BP neural network; hydropower unit; axis orbit; identification

Coupling Vibration Feature Extraction of Hot Continuous Rolling Mill Based on

Adaptive Frequency Domain Filtering and S Transform

LingQihui1, 2,YanXiaoqiang2,ZhangYifang2

(1.College of Mechanical Electrical Engineering, Hunan University of Science and Technology Xiangtan, 411201, China)

(2.School of Mechanical Engineering, University of Science and Technology Beijing Beijing, 100083, China)

Abstract Rolling mill vibration signals that are time-varying and random are often affected by noise interference, so that frequency domain analysis cannot identify and extract fault features. The adaptive frequency domain filtering method has been proposed to successfully separate noise signals and vibration characteristics based on short-time Fourier transform (STFT). First, according to STFT and a threshold set by the power method, the dominant frequencies of vibration signals in different time periods are automatically captured. After the vibration signal, hydraulic cylinder pressure signal, and servo valve reference signal have been captured by STFT, the hot continuous rolling mill is diagnosed with mechanical-hydraulic coupling vibration. With the combination method of discrete wavelet transform and S transform, the rolling mill vibration signal is analyzed, which determines that the rolling mill vibration start-up time is the investment time of the hydraulic pressure system, thus proving the existence of mechanical-hydraulic coupling vibration.

Keywords hot continuous rolling mill; coupling vibration; frequency domain filtering; S transform; vibration recognition

Application of Independent Component Analysis in

Automata Vibration Signal Process

XuXin1,PanHongxia1,PanMingzhi2

(1.School of Mechanical and Power Engineering，North University of China Taiyuan, 030051, China)

(2. School of Mechanical, Jin Zhong University Jinzhong, 030619, China)

Abstract The fault diagnosis accuracy of a working automaton can be improved when the interfering signals and noise are removed from the complex vibration signal under multi-interference and heavy noise. The basic theory of ICA (independent component analysis) is studied, and ICA based on improved particle swarm optimization is introduced into the simulation. A comparatively satisfactory separation effect is obtained, and practical data shows that the approach is feasible.

Keywords automaton; vibration signal; independent component analysis; improved particle swarm; signal separation

Estimation of the Unbalance of Rotor System Based on Robust Regression

Analysis

ZangTingpeng1,WenGuangrui1,2,3,LiaoYuhe1

(1.Key Laboratory of Education Ministry for Modern Design & Rotor-Bearing System,

Xi′an Jiaotong University Xi′an, 710049, China)

(2.State Key Laboratory for Strength and Vibration of Mechanical Structures,

Xi′an Jiaotong University Xi′an, 710049, China)

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

Abstract Rotor mass unbalance is the most common cause of excessive vibration in rotating machinery and can affect the work performance and safety operations of the system. The traditional least squares algorithm is sensitive to outliers in the process of estimating rotor system unbalance. By manually assigning different weight coefficients, the weighted least squares algorithm can reduce the impact of outliers, but requires practical experience and have deep analysis of the vibration data. In view of these problems, a new unbalance estimation method based on robust regression analysis is proposed. The effect of outliers is automatically eliminated by an optimized objective function. Experimental results show that the proposed method can effectively reduce the influence of outliers and more accurately identify the unbalance of the rotor system.

Keywords robust regression analysis; rotor; least squares algorithm; unbalance

Influence of Mid-tower on Buffeting Performance of a Long-Span

Triple-Tower Suspension Bridge with Continuous Span

TaoTianyou,WangHao,LiAiqun

(Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education,

Southeast University Nanjing, 210096, China)

Abstract In order to investigate the influence of a mid-tower on the buffeting performance of a long-span triple-tower suspension bridge with continuous span, the first triple-tower suspension bridge in the world, the Taizhou Bridge, is taken as the research object. The influences of the type and longitudinal stiffness of a mid-tower on wind-induced buffeting responses of the long-span triple-tower suspension bridge with continuous span are studied using structural nonlinear time-domain analysis accompanied by a finite element model. The comparison between calculated and measured modal parameters of the Taizhou Bridge validates the accuracy of the established finite element model. The results show that an A-type mid-tower can significantly decrease the torsional buffeting displacements of the main girder with slightly suppressed vertical and lateral displacements when compared to a herringbone-type mid-tower. Increasing the longitudinal stiffness of the mid-tower can decrease the vertical and torsional buffeting displacements of the main girder to some extent, while hardly affecting the lateral displacements. Variation in the longitudinal stiffness of the mid-tower has feeble influence on the translational buffeting displacements of the side tower. The torsional displacement and displacement along the bridge deck are prominently decreased with the increment of longitudinal stiffness of the mid-tower with limits. Meanwhile, increased longitudinal stiffness of the mid-tower will slightly augment the torsional buffeting displacement of the side tower, and can positively suppress lateral buffeting displacement of the mid-tower to some extent.

Keywords triple-tower suspension bridge with continuous span; buffeting performance; type of mid-tower; stiffness of mid-tower; time-domain analysis

DT-CWT Domain Correlation Filter and Its Application in

Incipient Gearbox Fault Diagnosis

XuYonggang1,ZhaoGuoliang1，HouShaofei1，ZhangJianchang2

(1.Key Laboratory of Advanced Manufacturing Technology, Beijing University of Technology Beijing, 100124, China)

(2.Oil Transportation Plant 3 of Petro China Changqing Oilfield Company Yinchuan, 750006, China)

Abstract The conventional wavelet denoising method based on the simple threshold principle cannot always successfully extract the weak fault feature from the vibration signal with strong background noise, as the noise of different layers is individually estimated. Inspired by the fact that the wavelet transform coefficients of adjacent layers have some similarities where the signal is singular, a new method based on dual-tree complex wavelet transform and correlation filter is proposed. The method is an interactive process in which its parameters are adaptively selected and the noise can be efficiently reduced. More important, the faint component that is expected to be extracted will be retained. The defect frequency can be accurately found by the envelope demodulation analysis. As an improvement to the conventional wavelet transform domain correlation filter, it takes full advantage of dual-tree complex wavelet transform. Experimental and engineering application examples show the method′s effectiveness in incipient gearbox fault diagnosis.

Keywords dual-tree complex wavelet transform; correlation filtering; denoising; gearbox; incipient fault diagnosis

Determination of Dynamic Stiffness and Damping of Mounts in a Powertrain

Mounting System Based on the Requirement of NVH in Vehicle Level

LiuXiaoang1,LüZhaoping2,YinZhihong1,ShangguanWenbin1,YeBijun3

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

(2. SAIC-GM-Wuling Automobile Co, Ltd Liuzhou, 545007,China)

(3. Ningbo Tuopu Group Co., Ltd Ningbo, 315800,China)

Abstract A method for determining the dynamic stiffness and damping of mounts in a powertrain mounting system (PMS) is developed based on the limitation requirements for the vibrations of a seat track, and the noise at the driver′s ear on the right side. A calculated model with 13 degrees of freedom (DOFs) is proposed that includes 6 DOFs for the powertrain, 3 DOFs for the car body and 4 DOFs for the four unsprung masses. In the model, the stiffness and damping of a mount are simplified as a function of excitation frequency. The vibration transfer function (VTF) or noise transfer function (NTF) from the connecting point of mount and body to the vibration of seat track, and the noise at the driver′s ear on the right side, can be measured and calculated. The vibration or noise of the interested points is estimated under different driving conditions.

Keywords vibration and noise control; hydraulic engine mount; dynamic stiffness; determining of damping of a mount

Modeling of Fatigue Crack Growth for Filled Natural Rubber Materials

ShangguanWenbin1,2,DengJianxiang1,YuLiangwei1,WangXiaoli1,

DuanXiaocheng1,2,YanJiao3

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

(2. Ningbo Tuopu Group Co., Ltd Ningbo, 315800, China)

(3. Pan Asia Technical Automotive Center Co., Ltd Shanghai, 201201, China)

Abstract The fatigue crack growth (FCG) model refers to the relationship between crack growth rate (defined as crack growth length versus number of cycles) and maximum tearing energy, and is used to predict the fatigue life of a rubber damping component. Usually, some of the measured relationships of crack growth length and number of cycles in a fatigue crack growth experiment cannot be used to model FCG, due to the stress softening phenomenon of filled natural rubber materials. In this study, a data processing technique is first given to obtain effective data of crack growth length versus number of cycles. Second, based on the assumption that maximum strain energy density and maximum strain have the function of the power relationship under a uniaxial tensile load, the model for modeling relations of crack growth length and number of cycles under variable amplitude loading conditions is established. Third, by using the least-squares method, the optimization method for identifying model parameters is established. On the basis of the established relations of crack growth length and number of cycles, the model for describing relationships between crack growth rate and maximum tearing energy is built, and the numerical method to obtain the constants in the mode is given. Finally, the proposed established crack growth model is validated by comparing the measured and calculated fatigue life of rubber dumbbell specimens.

Keywords crack growth experiment; crack growth length; number of cycles; crack growth rate; maximum tearing energy; model parameter identification; variable amplitude loads

Experimental Study on Booming Noise Caused by Driveline Torsional Vibration

WangYuanwen1,DongDawei1,LuZhiwen1,SunMeiyun2,YanBing1

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

(2. CNR Tangshan Railway Vehicle Co., Ltd Tangshan, 063035,China)

Abstract For the low-speed booming noise problem of rear-wheel drive cars, the excitation sources, transfer paths and peak generating mechanism of booming noise are comprehensively analyzed with transfer path analysis and modal experimental methods. The excitation force mainly comes from torsional alternating moments of the final drive input, which acts on the rear axle in the form of a bearing reaction force, then transmits to the interior. The combined effects of multiple resonances result in peaks of 1102r/min and 1515r/min, but the resonant structures are different. Based on the aforementioned analyses, various measurements to reduce interior noise by reducing the torsional alternating moment are proposed, and a comprehensive evaluation is given. Verification experiments of better noise reduction measurements are carried out. The results show that the measurements are effective at reducing booming noise by up to 15dB, and that the research provides a new idea for solving similar problems.

Keywords booming noise; torsional vibration; transfer path; torsional vibration damper; dual mass flywheel

The Fault Diagnosis of Cracks in the Planetary Gear System of Wind Turbine

GuiYong1,2,HanQinkai1,LiZheng1,ChuFulei1

(1. The State Key Laboratory of Tribology, Tsinghua University Beijing, 100084, China)

(2. Department of Mechanical Engineering, Academy of Armored Force Engineering Beijing, 100072, China)

Abstract Cracks are a form of early failure in the planetary gear system of a wind turbine. Aiming to solve problems of crack diagnosis caused by the amplitude and frequency modulation from inevitable gear errors in planetary gear systems, a dynamic model containing various types of manufacturing errors is built and used to consider the influence of cracks on mesh stiffness and transmission error. Using numerical calculations, the sideband of the spectral envelope of the system with cracks on its planet, sun and ring gear are compared with the sideband of a normal system without cracks. The fault characteristic frequencies of the three parts are concluded. The crack fault experiment is carried out on a test bench of a wind turbine gearbox, and its results are helpful for the fault detection and localization of the planetary gear system in wind turbine gear systems.

Keywords wind turbine; planetary gear system; cracks; faults diagnosis

Research on Control Method for Semi-active Heavy Truck Cab Mounting System

HuangShanyun1,ChenBin2,TuFengchen3,ChenZhaobo1,YuDong1

(1.School of Mechatronics Engineering, Harbin Institute of Technology Harbin, 150001, China)

(2.School of Mechanical and Power Engineering, Harbin University of Science and Technology Harbin, 150080, China)

(3.Zhuzhou Times New Material Technology Co., Ltd Zhuzhou, 412000, China)

Abstract In order to reduce vibrations in a heavy truck cab, a lumped mass model is built to find an efficient control method for the semi-active cab mounting system based on a magnetorheological damper. The controller is designed using PID control theory and the fuzzy optimum control method. The parameters of the fuzzy optimum controller are optimized by using the dynamic characteristics experimental data of the magnetorheological damper. By taking the acceleration magnitude of the cab centroid′s vertical, roll and pitch as the control objectives, the numerical simulation is carried out with ADAMS/Simulink software, and two control strategies are applied and compared. Experiments with a real truck experiencing road excitation are performed. The simulated and experimental results show that the PID and fuzzy optimum control can reduce the vibration of the cab compared with the passive status, and the fuzzy optimum control method is more effective.

Keywords vibration control; cab mounting system; magnetorheological damper; PID control; fuzzy optimal control

Fault Diagnosis of Bearings Based on Baby Wavelet Deployment and

Coefficients Integration

ZhangDan1，SuiWentao2

(1. School of Electrical & Electronic Engineering, Shandong University of Technology Zibo, 255049, China)

(2. School of Mechanical Engineering, Shandong University of Technology Zibo, 255049, China)

Abstract In light of the difficulties of feature extraction of early faults in rolling element bearings, a method based on baby wavelet deployment and coefficients integration is proposed for fault diagnosis. First, the baby wavelets are deployed, and wavelet transform is conducted. The wavelet coefficients at different scales are then integrated according to the proposed peakedness indicator. Finally, the autocorrelation spectrum is adopted to restrain noise and highlight fault information. The effectiveness and advantages of the proposed method are proven through simulated and experimental signals. The results show that the weak fault features can be extracted, and the early fault diagnosis of rolling bearings is realized through the proposed method.

Keywords baby wavelet deployment; coefficients integration; fault diagnosis; rolling element bearings

Research on the Characteristics of Flow-Induced Vibration of

Bulkhead Gate Based on Chaotic Theory

LuoBeier,WangJunxing,ZhouJianfeng,ZhangYingying

(State Key Laboratory of Water Resources and Hydropower Engineering Science,

Wuhan University Wuhan, 430072, China)

Abstract Chaotic characteristics analyses are conducted in a hydroelastic model test to measure the acceleration response data when different gates open due to the complexity of flow-induced vibration. First, phase space reconstruction is carried out in the measured data using average mutual information and the averaged false nearest neighbor method to calculate the optimum time delay and optimal embedding dimension. Based on these embedding parameters, the correlation dimensionD2and the largest Lyapunov exponent1are calculated for each group, and the distribution law of calculation parameters is analyzed. The results show that: the lateral gate vibration is more complex than other directions, while the gate vibration complexity is more remarkable in intermediate openings; lower dimension (D2= 3.342 ～ 5.130) chaotic attractors are present in vertical gate vibration and flow vibration, which means the vibration law of the gate along the vertical direction and flow direction can be described by fewer independent variables; and finally,1of each measuring point variation with gate opening presents the trend “both sides small and the middle large”, which indicates that the vibration forecast accuracy is lower in intermediate openings.

Keywords bulkhead gate; flow-induced vibration; chaos; phase space reconstruction; correlation dimension; Lyapunov exponent

《振動、測試與診斷》第七屆編委會名單

顧問委員會： 楊叔子 聞邦椿 蔡鶴皋 鐘 掘 伍小平 胡海巖 高金吉 葉聲華 任露泉 譚建榮

主任委員： 熊詩波

《振動、測試與診斷》編輯部

主 編： 趙淳生

副主編： 姚志遠 鄭海起 張義民 張憲民 趙丁選 賈振元 趙玉龍 夏裕彬

常務編委： (以拼音為序) 蔡敢為 常 佶 陳 進 陳 南 陳定方 陳維山 褚祥誠 杜永祚 顧 明 侯書軍 黃耀志 賈振元 蔣書運 史鐵林 王廣林 楊 明 楊世錫 姚志遠 尹周平 應懷樵 于德介 張建輝 張憲民 張小棟 張義民 趙淳生 趙丁選 趙玉龍 鄭海起 朱真才

編輯部主任： 姚志遠

編輯部副主任： 陳 琪

《振動、測試與診斷》征稿簡則

一、征稿范圍

《振動、測試與診斷》主要刊登有關振動利用、動態測試和故障診斷的標準、測試理論和測試手段的論文，包括試驗測試技術、測試儀器的研制方法和系統組成、信號分析、數據處理、參數識別、故障診斷以及有關裝置的設計、使用、控制、標定和校準等。不拘泥于行業(如機械、交通、農業、生物、能源、航空、航天、航海、建筑、地震等)和測試項目(如振動、沖擊、力位移、噪聲等)。

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10. 本刊對上決審會進行評議的稿件須進行查重處理，若查重結果超過20%，直接退稿，請作者認真對待。

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三、編輯部地址: 南京市御道街29號《振動、測試與診斷》編輯部(210016)

網址：http:∥zdcs.nuaa.edu.cn 電話、傳真: 025-84893332 E-mail:qchen@nuaa.edu.cn

New Development of Valve-Less Piezoelectric Pump Imitating Caudal-Fin

ZhangJianhui1,2,HuXiaoqi3,ZhaoChunsheng2

(1.College of Mechanical and Electrical Engineering, Guangzhou University Guangzhou, 510006, China) (2.State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics Nanjing, 210016, China) (3. College of Engineering and Design, Lishui University Lishui, 323000, China)

With continual developments in medicine and health care, parts such as microminiaturization, stability of transferring fluid, and flow pulsation and backflow for piezoelectric pumps, especially valve-less piezoelectric pumps, have increased their requirements in recent years. Volume piezoelectric pumps cannot generate continuous output and pressure due to their inherent period and fluctuation, nor can they avoid the phenomena of backflow, pulsation and choking of the micro valve block. Meanwhile, rotation piezoelectric pumps cannot meet the requirements of security transport and stabilization in vivo due to their own complexity and uncontrollability. As a result, the exploration of novel operating principles of piezoelectric pumps becomes particularly important. Based on the phenomenon of driving fluid with single-flow by swing, this paper summarizes the research on three kinds of caudal-fin-type swing type valve-less piezoelectric pumps, which are developed in the fluid driving unit of the State Key Laboratory of Mechanics and Control of Mechanical Structures in Nanjing University of Aeronautics and Astronautics.

spiezoelectric; valve-less pump; imitating caudal-fin; swing vibrator