第39卷第4期英文摘要

ProgressandApplicationofTie-linePowerControlandWholeProcessSimulationTechnologyofInterconnectedPowerGrid

TANGYong

(State Key Laboratory of Power Grid Safety and Energy Conservation, China Electrical Power Research Institute Beijing, 100192, China)

AbstractIn order to solve the problems faced by the security of interconnected power grids in China, the principle and method of power fluctuation and the oscillation of tie line are put forward, and a multi-time-scale dynamic whole-process model and its simulation method of power system in China are developed. Base on them, the technical system of the dynamic process security defense of interconnected power grids is established, which can improve the effective defense against interruption of tie line chain and accurately simulate the dynamic process of tens of minutes or even hours. It provides a technical guarantee for the safe and stable operation of China power grid, which reaches the highest level in the world.

Keywordsinterconnected power grid; tie line; power fluctuation; power oscillation; whole-process dynamic simulation

DynamicInteractionTestBetweenSubsoilandMulti-ribbedCompositeWallStructure

LUJunlong1,ZHANGYin2

(1. School of Civil Engineering and Architecture, Xi′an University of Technology Xi′an, 710048, China)(2. School of Civil Engineering, Xi′an University of Architecture and Technology Xi′an, 710055, China)

AbstractTo study the regulations for multi-ribbed composite wall on seismic response and damage mechanism affected by the interaction between loess subsoil and structure, the shake table tests are carried out for the multi-ribbed composite wall structure scaled in 1/15 considering the interaction between the subsoil and the structure as well as the rigid foundation. After the unidirectional, bidirectional and three directional EL-Centro wave and Tianjin wave are input under different intensifies, the acceleration responses are tested. Then the lateral acceleration responses considering the interaction were compared to the rigid foundation as the destruction phenomenon. And the amplify effect to earthquake waves for subsoil and that of interaction for seismic response of floors are analyzed. As a result, after earthquake waves are input, the failure model of the interaction system is cracking on subsoil, while the failure model of the multi-ribbed composite wall structure with rigid foundation is slippage across bottom joint slit. The seismic amplify effects for subsoil are related to frequency characters, intensify, and inputting to earthquake waves. The influence by the interaction for lateral dynamic response at each floor is different, and the interaction is also affected by frequency spectrum of earthquake and seismic intensify. As the interaction coefficients are close to the amplify coefficients of subsoil, the adjustment coefficients of seismic affection can be seen as the amplify coefficients of subsoil.

Keywordsinteraction; seismic response; failure mechanism; multi-ribbed composite wall structure; shaking table test

FrequencyOptimizationandDisturbanceResponsePredictionofaLargeFlexibleDeployableAntenna

WANGPengpeng1,WANGXiaoliang2

(1. Xi′an Institute of Space Radio Technology Xi′an, 710100, China)(2. Shaanxi Institute for Food and Drug Control Xi′an, 710065, China)

AbstractThe high flexibility and low damping of large deployable antenna has been proposed as critical requirement not only for the stability control of the antenna itself, but also for the attitude control of the satellite. Under the development of a large flexible deployed antenna, a frequency optimization design and disturbance response analyses are conducted for the antenna. Moreover, an improvement of the designis achieved by the sensitivity analysis of the modal frequency to the stiffness of the support structure and the stiffness of the scanning mechanism. Modal analysis and test are carried out, and the influence of pitch angle and azimuth angle to the moment of inertia and modal frequencies are given for -10°～25° and -10°～10° combination modes. Further simulation investigates the root mean square and the pointing error response of the antenna reflector under a given satellite disturbance, and the simulation results revealed that the large deployable antenna is insensitive to the disturbance after the frequency optimization.

Keywordsantenna structure; natural frequency; mode; disturbance response

TransientVibrationCharacteristicsofHelicalGearBasedonMeshingStiffnessofBackTeeth

WANGFeng1,2，ZHANGJian1，XUXing1，CHENLong1，F(xiàn)ANGZongde3，ZHOUZhiguang4，SUNXiaoqiang1

(1. Automotive Engineering Research Institute, Jiangsu University Zhenjiang, 212013, China)(2. Key Laboratory of Advanced Manufacture Technology for Automobile Parts(Chongqing University of Technology)， Ministry of Education Chongqing, 400054, China)(3. School of Mechanical Engineering, Northwestern Polytechnical University Xi′an, 710072, China)(4. New Energy Development Department Powertrain Technology Center, Chery Automobile Co., Ltd. Wuhu, 241009, China)

AbstractThe transient vibration amplification characteristics of high-speed helical gears considering the back contact stiffness of gears is studied. In light of this problem, the dynamic meshing stiffness of helical gear is introduced. The parameter implies the coupling mechanism of meshing time and vibration displacement of the tooth surface, as well as the actual load contact state of the tooth surface at the high-speed transient condition. First, a 6-degree of freedom helical gear transient vibration model is established based on the dynamic meshing stiffness and backlash excitations. Then, the influences of different backlash and back sided impacts on the transient vibration characteristics are thoroughly analyzed. Finally, a helical gear transient torsional vibration test rig with enclosed power flow is built, and the transient vibration characteristics of helical gears with contact stiffness of the back teeth are verified. The research not only has great theoretical significance, but is also beneficial to the popularization and application of the helical gear transmission system in the aviation transmission and the new energy transmission system, and further improve the transient vibration and noise quality of high-speed gear system.

Keywordshigh-speed gear; tooth back contact; dynamic meshing stiffness; transient vibration; torsional vibration measurement

MonitoringMillingCutterWearConditionBasedonCuttingCurrentCoefficients

LIHongkun1,ZHANGMengzhe1,HAOBaitian1,ZHANGZhixin2

(1. School of Mechanical Engineering, Dalian University of Technology Dalian, 116024, China)(2. School of Mechanical Engineering, Dalian University Dalian, 116622, China)

AbstractThe cutting condition independent method based on force model coefficients is applied to monitor tool wear status. However, its application in an actual industrial environment is restricted due to multiple reasons, such as the interference in normal processing, lagging in real-time tracking, difficulties in sensor installation and high cost. In light of these problems, spindle cutting current coefficients are introduced. First, the cutting current model of a sharp tool is built with cutting force coefficients and spindle current. Then, the coefficients are identified, and the cutting current of a sharp real tool with the same parameters as the simulated model is estimated in real-time. The difference between the actual cutting current from that of the estimated value is tracked and the wear status is judged; Finally, the correctness and validity of the method are verified by experiments and comparison with force signals. The experimental results show that this method can replace the method based on cutting force coefficients. The proposed method recognizes the wear status without interference and narrowly lags behind in real-time tracking.

Keywordsspindle current; cutting current coefficients; milling cutter wear; condition monitoring

WeakFaultFeatureExtractionMethodforRollingBearingsBasedonSVD-EEMDandTEOEnergySpectrum

ZHANGChen1,2,ZHAORongzhen1,DENGLinfeng1,WUYaochun1

(1. School of Mechanical & Electronic Engineering, Lanzhou University of Technology Lanzhou, 730050, China)(2. Armored Vehicle Technology Department, Engineering University of PAP, Campus of Urumqi Urumqi, 830049, China)

AbstractA sensitive feature extraction method is proposed to describe the weak state of rolling bearing. It combines the singular value decomposition (SVD) with the ensemble empirical mode decomposition (EEMD). The Hankel matrix is reconstructed by phase space reconstruction of the collected signal to improve the quality of signal failure. The order of noise reduction is determined according to the singular value difference spectrum of the matrix. The noise-reduced signals are decomposed into 11 intrinsic mode functions (IMF) and one residual using EEMD. According to the established kurtosis-mean square error criterion, one of the most effective states sensitive IMF is selected, and its corresponding Teager energy operator (TEO) is calculated, The identification of weak failure mode of rolling bearing is realized by Fourier transform of TEO. The new method is compared with the traditional EEMD-Hilbert method and EEMD-TEO method in case of the opening rolling bearing fault signal of the US west reserve university. The results show that the sensitive features extracted by this method can accurately identify the cycle frequency of rolling bearing fault and accurately identify the fault type, which provides an effective method for the weak feature extraction of rolling bearing.

Keywordsensemble empirical mode decomposition (EEMD) method; singular value decomposition; Teager energy spectrum; feature extraction

AnANFISMethodtoImproveSSVEP-BCIAnti-blinkingStability

LUZhufeng1,ZHANGXiaodong1,2,ZHANGLiming1,LIHanzhe1,LIRui1,2

(1.School of Mechanical Engineering, Xi′an Jiaotong University Xi′an, 710049, China)(2. Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System, Xi′an Jiaotong University Xi′an, 710049, China)

AbstractThe electrooculography (EOG) artifact removal for steady-state visual evoked potentials (SSVEP) is studied. An EOG artifact removal method for electroencephalogram (EEG) without ocular electrode based on adaptive neuro-fuzzy inference system (ANFIS) is proposed, and the experiments are carried out to prove the improvement of SSVEP-BCI′s stability under random blinking. It tackles the stability of brain control interface (BCI) under artifact interference and takes the stability of SSVEP-BCI under random blinking as the key point. The proposed method approximates the nonlinear transforming function from the EOG source to EOG artifact with ANFIS to cancel the EOG artifact from EEG. The EOG artifact is deleted in an adaptive noise cancellation (ANC) after the source obtained from the prefrontal lobe′s EEG passing through a tapped delay line (TDL) into the cancellation. All the parameters and functions are elaborated based on the experiments of steady-state visual stimulation under random blinking. The proposed method cancel EOG artifact in SSVEP while maintaining valid information on steady-state visual stimulation. The recognition accuracy is 6.25% and 10% higher than that of the classical band-pass filter and traditional ICA respectively, thus ensure the stability of SSVEP-BCI under random blinking.

Keywordsbrain control interface (BCI); electroencephalogram (EEG); steady-state visual evoked potentials (SSVEP); electrooculography artifact; adaptive neuro-fuzzy inference system (ANFIS)

ExperimentalWindPressureDistributiononLarge-SpanThree-CenteredCylindricalReticulatedShell

ZHANGQinghua1,MAWenyong2,WANGQiang3,FANGPingzhi4

(1. School of Civil Engineering and Communication, North China University of Water Resources and Electric Power Zhengzhou, 450045, China)(2. Wind Engineering Research Center, Shijiazhuang Tiedao University Shijiazhuang, 050043, China)(3. China Three Gorges Corporation Fujian Energy Investment Co., Ltd. Fuzhou, 350003, Chna)(4. Shanghai Typhoon Institute of China Meteorological Administration Shanghai, 200030, China)

AbstractThe wind pressure characteristics of the surface of a large-span three-centered cylindrical reticulated shell are investigated using a rigid model in a atmospheric boundary layer wind tunnel and synchronized pressure measuring tests. The mean and fluctuating wind pressure distribution characteristics with typical wind directions, the power spectrum and the coherence of the fluctuating wind pressure between different measuring points are experimentally analyzed. The results show that the wind direction has a significant impact on the wind pressure distribution on the reticulated shell surface. In general, the windward of the reticulated shell is the positive pressure area; a negative pressure zone is formed on the top of shell under the impact of characteristic turbulence, such as the separation and reattachment of the air flow, and also the vortex shedding; at the edge of the shell, the wind pressure is obviously influenced by the column and conical vortexes, and violently changes. Furthermore, single peaks are also observed in the fluctuating wind power spectrum in most areas of the windward. It is similar to the typical longitudinal wind turbulence spectrum and can be deduced that the incoming wind turbulence is the major contribution to the along-wind pressure. In addition, the attenuation difference of the coherence is changed with the wind directions, and the coherence of the measuring points along the wind direction is stronger than those along the cross-wind direction.

Keywordsthree-centered cylindrical reticulated shell; wind tunnel test; wind pressure distribution; power spectral density (PSD); correlation

NonlinearVibrationCharacteristicAnalysisofBrakeGroanBasedonRoadTests

ZHANGLijun1,2，ZHANGXiyu1,2，MENGDejian1,2，YUZhuoping1,2

(1. School of Automotive Engineering, Tongji University Shanghai, 201804, China)(2. Collaborative Innovation Center for Intelligent New Energy Vehicle, Tongji University Shanghai, 201804, China)

AbstractOrder to probe into the original nonlinear characteristics of fictional brake groan, two test conditions are devised, which are starting on level road under D shift and coasting on gradient road under neutral gear. Under these conditions caliper 3D vibration signals are sampled and analyzed in time domain, time-frequency domain and phase diagram. The analysis results show that the brake groan during D shift starting on level road conditions is an obvious short-time impact with a wide frequency band. The vibration amplitudes increase with the augment of brake pressure, and the durations rise up with the increase of the pressure reduction rate. Brake groan during neutral gear coasting on gradient road conditions, can be a short-time impact with a wide frequency band, or a periodic stationary vibration with multi-frequencies. Under different relative velocities, periodic, period-doubling, multi coupled period vibrations, even chaotic vibration will occur due to the nonlinear friction-velocity characteristics. Three basic frequencies and their coupled relationships indicate that the frictional mechanism of brake groan is not only induced by the stick-slip effect, but also the nonlinear mode coupling effect in a chassis corner system.

Keywordsfrictional groan; test condition; friction-velocity characteristics; stick-slip vibration; mode coupling

MeasurementofToothRootStraininPlanetaryGearboxwithFiberBraggGrating

NIUHang1,HOUChenggang1,ZHANGXiaodong1,2,ZHAOXindan1

(1.School of Mechanical Engineering, Xi′an Jiaotong University Xi′an, 710049, China)(2. Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System, Xi′an Jiaotong University Xi′an, 710049, China)

AbstractAn approach to measure the tooth root strain of the ring gear in planetary gearboxes using fiber Bragg grating (FBG) is proposed. First, the computing method of the ring gear tooth root strain is studied, and the tooth root strain of the ring gear is simulated. Second, the measurement method is deeply analyzed from three aspects: the strain sensing characteristics of FBG, the installation of FBG, and the structure of the measurement system. Finally, the measurement is carried out. The tooth root strain of the ring gear obtained from the experiment shows obvious single and double meshing sections, meanwhile the range of each section and the strain values at each section are similar with that of the theoretical results, which proves that the tooth root strain of the ring gear can be accurately acquired with the proposed method. Compared with the traditional methods, the new method is more suitable for the real-time measurement of the ring gear tooth root strain in the narrow space of planetary gearboxes.

Keywordsplanetary gearbox; tooth root strain; ring gear; fiber Bragg grating (FBG); dynamic measurement

ParallelIterativeCoupledMethodforThermalEnvironmentofWingandThermalModalAnalysis

HUANGJie1,YAOWeixing2

(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)

AbstractIn order to analyze the thermal environment of the wing, a parallel iterative coupled method is presented in this paper. The aerodynamic heating and structural thermal problems are analyzed by the finite volume method (FVM) and finite element method (FEM), respectively. Moreover, the data exchanges are conducted by an interpolation method based on a virtual space. A circular tube example is analyzed, and for the stagnation temperature at two second, the relative error between the calculated value and the tested one is 5.16%, so the analysis precision of the parallel iterative coupled method can be verified. Finally, the thermal environment and thermal modal of the wing are analyzed. The results show that the maximum temperature of the wing is linear with Mach number, and the maximum temperature obtained by the uncoupled method is 342.2 K higher than that obtained by the coupled method. The reason is that the uncoupled method does not consider the coupled effect between the aerodynamic heating and structural thermal problems. Compared with the additional geometrical stiffness caused by thermal stress, the decrease of the material stiffness in the thermal environment is the main factor for the stiffness and natural frequency of the wing. In addition, as Mach number increases, the lower order natural frequency decreases faster than the higher order one.

Keywordswing；thermal environment；parallel coupled method；thermal stiffness；thermal modal

AnalysisandDiagnosisofRotorCrackFaultBasedonMorphologicalCharacteristicsofAxisOrbits

XIANGLing,ZHANGYue

(Mechanical Engineering Department, North China Electric Power University Baoding, 071003, China)

AbstractWhen the crack and rub-impact coexist in the rotor system, nonlinear behaviors of the system become more complex. In light of this problem, the rotor crack faults are analyzed and diagnose. First, the dynamic model of crack and the rub-impact rotor is established, a diagnosis method of crack fault is proposed based on the change of morphological characteristics of axis orbits in multiple faults. The morphological characteristics of axis orbits are analyzed around the 1/2 subcritical speed zone. The results show that the shapes of inner loops are changed and the offset direction of inner loops rotates a certain angle in the neighborhood of 1/2 subcritical speed. Axis orbits around the 1/2 subcritical speed zone are evidently different between the crack and rub-impact rotor and the rub-impact rotor. Then, the analysis of morphological characteristics of axis orbits provides a simple and novel method for the preliminary diagnosis of crack fault in the multi-fault rotor system, which improves the efficiency of fault diagnosis. Meanwhile, the dynamic response of different rotor systems is analyzed by the bifurcation and frequency spectra. Finally, the experiments are conducted on Bently rotor test rig to verify the simulation results of the crack rotor system.

Keywordsrotor; crack; rub-impact; subcritical speed; axis orbit

AmbientVibrationMonitoringandDynamicCharacteristicsIdentificationofAdjacentStructuresSeparatedbyanExpansionJoint

LIUPei,ZHUHaixin,LIANPengyu,YANGWeiguo

(School of Civil Engineering, Beijing Jiaotong University Beijing, 100044, China)

AbstractIn light of the effect of the technical solution of the separation joint on the dynamic characteristics of as-built adjacent structures, ambient vibration tests are conducted in two adjacent reinforced concrete frame-shear wall structures separated by an expansion joint. Modes including natural frequencies, damping ratios, and mode shapes are identified. The magnitude-squared coherences are calculated based on the test data obtained from the sensors located on the two sides of the expansion joint simultaneously. Long term monitoring of the vibrations of two adjacent structures is conducted. The trends of natural frequencies of the first three modes varying with the temperature are obtained. The finite element modeling method for the adjacent structures taking into account the expansion joint under different temperatures is proposed. The results show that the dynamic characteristics of the two adjacent structures under ambient vibration are the same due to the continuous floor paving bricks across the expansion joint. The two adjacent structures form a system. The first two natural frequencies almost have no change with the increase of the temperature. The third natural frequency (the one corresponding to the torsional mode due to the continuity of the expansion joint) increases significantly with the increase of the temperature. Slabs with the same width as the separation gap and different elastic moduli are used to simulate the link between the two adjacent structures due to the expansion joint.

Keywordsambient vibration test; dynamic characteristics; expansion joint; long-term monitoring; temperature

DesignandResearchofaNovelPiezoelectricLinearMotorwithMultipleWorkingMode

SUNMengxin1,2,HUANGWeiqing2,3,WANGYin4,FENGYong1,ZHANGMin1

(1. School of Mechanical Engineering, Nanjing Institute of Technology Nanjing, 211167, China)(2. State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics Nanjing, 210016, China)(3. School of Mechanical and Electrical Engineering, Guangzhou University Guangzhou, 510000, China)(4. Research Center of Precise Instrument, Huaqiao University Xiamen, 361021,China)

AbstractA novel non-resonant piezoelectric linear motor with multiple working mode is proposed in the paper. Design and modeling of the stator is presented and the working mechanism of three working mode are introduced. The three working mode is continuous actuation mode, alternative step actuation mode and one-step actuation mode. With the help of finite element method (FEM) software, the arrangement of motor, clap mechanism and preload mechanism are designed and researched. The prototype is manufactured to validate the feasibility of motor under the three working mode. Experiment results show that, the velocity of motor is 446.4 μm/s under sine signal with a voltage of 100 V and a frequency of 100 Hz in continuous actuation mode. In alternative step actuation mode, the velocity of motor is 6 031 μm/s with a voltage of 100 V and a frequency of 100 Hz. In one-step actuation mode, the average step distance is 333.33 nm with a voltage of 30 V and a frequency of 1 Hz. The novel linear motor can meet different demands under multiple situation.

Keywordspiezoelectric linear motor; non-resonant; multiple working mode; high precision drive

AnAdaptive-PassiveTunedMassDamperSystem

WANGLiangkun1,SHIWeixing1,WANGHongtao2,LUZheng1

(1. Department of Disaster Mitigation for Structures, Tongji University Shanghai, 200092, China)(2. Shanghai Real Estate Science Research Institute Shanghai, 200031, China)

AbstractTuned mass damper (TMD) in the engineering application is sensitive to a frequency which is difficult to adjust. In light of this problem, this paper proposes an adaptive-passive TMD. It includes, besides the damper, the variable mass, spring, servo control system, and driving system. The servo control system consists of an acceleration sensor and a single chip computer circuit board which is used to receive the structural acceleration sensor signals under ambient excitation. The short-time Fourier transform (STFT) is used to identify the first order natural frequency of the structure and adaptively change the quality of the TMD to adjust the frequency of TMD and recognize the frequency of the main structure. The feasibility, reliability, and validity of the adaptive-passive TMD are verified by the pedestrian bridge model test. The experimental results show that the adaptive-passive TMD can accurately identify the vertical vibration frequency of the model structure and retune its frequency to the same frequency. Freedom vibration tests and forced vibration tests show that compared with the mistuned TMD, the retuned TMD can improve the equivalent damping ratio of the pedestrian model, and reduce the peak acceleration response and root-mean-square (RMS) values.

Keywordsadaptive-passive tuned mass damper; passive control; short-time Fourier transform (STFT); modal test; response evaluation

AcousticCharacteristicsofUltrasonicSolidCoupling

TANGDonglin1，2,HULin1,2,TANGYanjin1,2,WUWeiping1,2,YUANBo1,2

(1.Key Laboratory of Petroleum and Natural Gas Equipment, Ministry of Education, Southwest Petroleum University Chengdu, 610500, China)(2.College of Mechanical and Electrical Engineering, Southwest Petroleum University Chengdu, 610500, China)

AbstractFor detection of rough surface workpiece by ultrasonic wave with solid coupling, the relationship between reflection coefficient, surface roughness and interface pressure of solid coupling interface is analyzed. A method for deducing the stiffness of dry coupling interface is put forward. The reflection coefficient is calculated by the quasi-static stiffness spring model. The correctness of the theory is verified by model comparison and experimental analysis. Compared with the experimental value, the maximum relative error is 3.56%. This model can provide a reliable theoretical data for the estimated value of the given pressure, which is required for achieving the desired effect in dry coupling ultrasonic testing under a certain roughness surface. Meanwhile, it is proved that the roughness of solid coupling interface can significantly reduce the coupling effect，and coupling performance can be improved by increasing the pressure between solid interfaces. By establishing a random rough interface model, the influence of the interface and interface pressure can be quantified.

Keywordsultrasonic testing；reflection coefficient；rough interface；solid coupling

NovelNaturalFrequencyTrackingandSpuriousFrequencyEliminationMethod

ZHOUHaotian1,3，ZHAOJie1，CAOWeizheng2，ZHAORui1，YUKaiping1，BAIYunhe1,3

(1. School of Astronautics, Harbin Institute of Technology Harbin, 150001, China)(2. College of Computer and Information Engineering, Heilongjiang University of Science and Technology Harbin, 150022, China)(3. The 54thResearch Institute of CETC Shijiazhuang, 050081, China)

AbstractConsidering the natural frequency estimation and spurious frequency elimination are common in time-varying modal parameter identification, a subspace tracking algorithm based on the novel information criterion is introduced. A post-process procedure for spurious modes elimination is proposed. Firstly, the pseudo modal parameters are obtained through the proposed subspace tracking identification method, then the fuzzy C-means clustering algorithm is implemented to acquire the initial pseudo natural frequencies, finally a moving data window is applied to select the pseudo natural frequencies by data comparison. The proposed validation method only needs an estimated active modes number. Numerical simulations with different frequency changing types indicats that the proposed method can reach higher calculation accuracy. The identification and validation method are verified through a modal parameters identification of a time-varying structure in the high temperature environment. The experiment shows that the proposed method has high application value.

Keywordsmodal parameter; vibration test; vibration frequency; time-varying structure; parameter identification

Multi-unbalancesIdentificationofRotorSystemIntegratedwithGA-PSOMethod

ZHANGRuxin1,WENGuangrui1,2,ZHANGZhifen1,XUBin1

(1. School of Mechanical Engineering, Xi′an Jiaotong University Xi′an, 710049, China)(2. School of Mechanical Engineering, Xinjiang University Urumqi, 830046, China)

AbstractTraditional balancing procedures need test weights for calculating correction masses, which are of inefficiency and high-cost. A novel online unbalance identification method for rotor system, which is based on integrated genetic algorithm and particle swarm optimization (GA-PSO), is proposed. The core of this method is to decompose the unbalance of rotor system into number, location, mass and phase. Theoretical unbalance responses and measured vibration are complemented in direct and inverse, and integrated GA-PSO is applied to identify the unbalance. Firstly, a new objective function is constructed by using regularization method. The sparse-representation of unbalanced vector can be acquired by using GA, then the unbalanced number can be identified. Secondly, PSO is applied to identify unbalanced locations, masses and phases, and the accuracy can be enhanced by narrowing the initial value of PSO. The simulation and experiments results show that the proposed methods can predict the rotor unbalance effectively and provide guidance for the dynamics balance without trial weights. The cost of subsequent rotor system dynamics balance can be decreased, and the efficiency can be increased.

Keywordsrotor; no trial weight balancing; genetic algorithm; regularization; particle swarm optimization

Uncertainty-BasedDamageIdentificationUsingModalIntervalAnalysisandImprovedAnalyticalRedundancyReduction

FANGSheng′en1,2，ZHANGBao1

(1. School of Civil Engineering, Fuzhou University Fuzhou, 350108, China)(2. National and Local United Research Center for Seismic and Disaster Informatization of Civil Engineering, Fuzhou University Fuzhou, 350108, China)

AbstractIn order to solve the easy overestimation of classic interval algorithms for uncertainty-based damage identification of structures, an identification method is developed incorporating modal interval analysis with improved analytical redundancy reduction (IARR). Firstly the equations of structural static equilibrium are replaced by a set of constraint equations. Then the proposed improved analytical redundancy reduction algorithm is used to eliminate the rotation variables in the equations and most important of all, to make the equations related to damage components stay in the same subset. After that, the equations are expanded to interval format through adopting interval variables. Modal interval analysis is executed to evaluate the satisfaction of each constraint equation, by which means damage can be located. An experimental steel beam under a static load is used to validate the proposed method. The constraint equations for each beam segment are established based on three random parameters related to the stiffness, the deflections and the load. The analysis results demonstrate that taking into account the test error and parameter uncertainties, the proposed method can effectively locate the minor damage according to the unsatisfied constraints.

Keywordsuncertainty-based damage identification; modal interval analysis; improved analytical redundancy reduction; constraint satisfaction problem; steel beam experiment

ExperimentalResearchonGallopingPropertiesofCarbonFiberCompositeCoreonOverheadLine

LIULiang1，YAOYiming1,JIANGXin1,CUIYun2,XINGYufeng2,LUYi1,ZHANGXu1,DENGChun1

(1. Electric Power Research Institute of State Grid Jibei Electric Power Company Beijing, 100045, China)(2. School of Aeronautic Science and Engineering,Beihang University Beijing, 100191, China)

AbstractAn experimental research on the galloping properties of carbon fiber composite core without ice-covered of single span overhead line is developed by converting the wind excitation to periodic variation of the wire length. Corresponding with experimental research, a parametric resonance model of simply-supported cable structure is adopted to simulate conductor galloping induced by transverse wind load. The galloping phenomenon of aluminum cable steel reinforced and carbon fiber composite core with same cross-section dimensions and load conditions is compared and analyzed. The galloping modes for two cable systems under different exciting frequencies observed by experiment are explained from the perspective of parametric resonance dynamic instability region reasonably. The experimental results show that under the same static tension loading, compared to the traditional aluminum cable steel reinforced, carbon fiber composite core with the same cross-section size is more difficult to be galloping.

Keywordscarbon fiber composite core; galloping; experiment without ice-covered; parametric resonance

RollingBearingVibrationSignalDe-noisingMethodBasedonMBCV-EWTandSingularValueDifferenceSpectrum

WANGYaping,CUIWei,GEJianghua,XUDi，LIYunfei

(School of Mechanical and Dynamic Engineering, Harbin University of Science and Technology Harbin, 150080, China)

AbstractA signal de-noising method combining maximum between-cluster variance-empirical wavelet transform (MBCV-EWT) with singular value difference spectrum is proposed. It helps rolling bearing to overcome pattern aliasing and ensure the integrity and independence of each frequency component during vibration signal de-noising. First, in light of the uncertainty of traditional interval partitioning, an MBCV-EWT signal decomposition method is proposed. The signal spectrum is adaptively divided by the maximum inter-class variance, and a band-pass filter is constructed on each partition interval. Then, aiming at the redundancy of AM-FM component, impulse index is proposed to be the screening criteria of AM-FM and the best component is selected as a follow-up target. Finally, singular value decomposition is used for AM-FM. Signal de-noising is achieved according to the singular value difference spectrum. The simulation and experimental results show that the proposed method can achieve adaptive spectrum division. The problem of pattern aliasing can be effectively overcome, and the main components of the components obtained by decomposition are independent and complete. The amplitude modulation frequency components are accurately screened, and the effect of de-noising is obvious, so as to lay the foundation for fault recognition and prediction.

Keywordssignal de-noising； maximum between-cluster variance-empirical wavelet transform (MBCV-EWT)；singular value difference spectrum； rolling bearing

VibrationResponsePredictionandExperimentofShipLiquidPipingSystem

WUJianghai,YINZhiyong,SUNLinghan,SUNYudong

(China Ship Scientific Research Center, National Key Laboratory on Ship Vibration and Noise Wuxi, 214082, China)

AbstractVibration and noise of liquid filled pipeline is an important part of the noise of ship mechanical system. The vibration prediction of pipe is an important basis for ship acoustic design. Based on the vibration equations of the liquid pipe, the impedance matrix of components in the pipeline system is established by combing the theoretical analysis with the test result. Experiments results are carried out to verify the calculation method. The contrast results show: The results of this paper are in good agreement with both simulation results and test results. The calculation method of this paper has high accuracy and engineering application value in middle-high frequency range.

Keywordspiping system; transfer impedance; vibration response; fluid-structure interaction

DynamicAdjustofVibrationAngleforDual-driveVibratingSystem

CHENBing,MOWei,XUChuanlei,ZHANGLijie,LIUChang

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

AbstractThe vibration angle greatly affects the performance of the vibrating machine in screening efficiency and conveying speed. In order to achieve the dynamic adjustment of the vibration angle, the influence of the motors′ supply frequencies on the vibration angle is studied with a dual-machine vibrating system. First, a dynamic model is established using the Lagrange method. The theoretical analysis demonstrates that two vibrating motors achieve stable synchronization at different supply frequencies, but the vibration angle changes. Then, the simulation model is established by the numerical method. The elliptical trajectory of the system is obtained and the law of the vibration angle with the supply frequency is analyzed. Finally, the experiment of the dual-driven elliptical vibrating machine is carried out to verify simulation results. The simulation and experimental results show that the stable synchronous state of the vibrating system changes and the vibration angle is adjusted while the frequencies of the two vibrating motors are changed and under the condition of self-synchronization.

Keywordsself-synchronization; elliptical vibrating machine; vibration angle; simulation experiment

ElectrodynamicPerformanceandItsConstitutiveModelforSMAPiezoelectricCompositeControlDevice

ZHANMeng1,2,WANGSheliang2,ZHAOYun3

(1. College of Architecture Engineering, HuangHuai University Zhumadian, 463000,China)(2. College of Civil Engineering, Xi′an University of Architecture and Technology Xi′an, 710055, China)(3. College of Architecture Engineering, Tianjin University Tianjin, 300000, China)

AbstractTo solve the problem that the control force of shape memory alloy(SMA) damper is not adjustable and piezoelectric friction damper is difficult to start up, a novel composite control device whose SMA unit and piezoelectric friction unit work in turn is proposed; and the corresponding electrodynamic property test is carried out. On the basis of the experiment data, BP neural network model for control device is established which takes the sign of velocity, voltage and displacement as input neurons. Results show that the hysteresis curve of the composite control device is full and basically symmetric; and the work performance is stable. As the voltage increases, the area of the hysteresis loop increases gradually, and the energy dissipation capacity increases. At the displacement amplitude of 12mm, the lap energy dissipation in 120V voltage increases by 138.23%, and the equivalent damping ratio increases by 94.23%. The damping device achieved by the combination of two intelligent materials has good energy-dissipating capacity and strong adaptability, and it can be better used for damping control of engineering structures. BP network prediction model can well track the output of the SMA composite control device, and the optimized BP network is more stable and can more quickly get error smaller network model; the neural network algorithm provides a new way for the establishment and application of constitutive model of SMA composite damping device.

Keywordsshape memory alloy; piezoelectric ceramics; mechanical property test; neural networks; constitutive model

BlindSeparationofCorrelatedSourcesBasedonModifiedS-TransformandICA

WEIChenglong1，ZHOUYiqi1，LIRui1，YUGang2

(1. School of Mechanical Engineering, Shandong University Jinan, 250061, China)(2. School of Automation and Electrical Engineering, University of Jinan Jinan, 250061, China)

AbstractThe mechanical vibration source signals with common frequency components cannot satisfy a statistically independent condition and be directly separated by a traditional blind source separation method. In order to solve this problem, a novel correlated source separation method based on modified S-transform (MST) and independent component analysis (ICA) is proposed. First of all, the modified S-transform is used to the time-frequency preprocessing of observation signals, taking advantage of the vector angle of the components in the real and imaginary parts of the time-frequency domain, and identifying and eliminating the dependent components in the mixed signals to ensure that the new reconstruction signals satisfy the independence condition. Then, using the negative entropy as an independent measure, the separation matrix is estimated based on the fast fixed-point independent components analysis. Finally, the correlated source signals are recovered through the matrix separating the initial observation signals and quantitatively calculated the contribution ratio of each vibration source. The effectiveness of proposed method in correlated source separation is verified by simulation and experiment results.

Keywordscorrelated sources separation; modified S-transform; independent component analysis; separation matrix estimation

RelationshipBetweenVibrationsofBearing-HousingSystemandLocalizedFaultSizes

LIUJing1,2,XUZidan1,2,TANGChangke1,2,WANGLinfeng1,2

(1. State Key Laboratory of Mechanical Transmission, Chongqing University Chongqing，400044，China)(2. College of Mechanical Engineering, Chongqing University Chongqing, 400044, China)

AbstractThe relationship between the localized fault sizes and the vibrations of the bearing-housing system is an important parameter for the accurate diagnosis of the bearing faults. To study the influences of the fault sizes on the system vibrations, a dynamic finite element model for a bearing-housing system with a localized fault is proposed. It can consider the deformations and gravity of the system components, as well as the contacts and frictions between the mating components of the bearing. Vibration characteristics of the system caused by the fault with different sizes are studied. The relationship between the fault sizes and system vibrations are obtained. The results can provide a method for predicting the vibration characteristics of the system. It seems that this work also can provide some useful foundations for the accurate fault defection and diagnosis of the bearing-housing system.

Keywordsbearing-housing system; localized fault; fault size; dynamics

CollapseAnalysis-BasedSeismicDamageEvaluationofContinuousGirderBridge

LIYale1,ZONGZhouhong2,HUANGXueyang3,4,LINYuanzheng2,XIAJian3,4

(1. School of Architectural Engineering, Jiangsu Open University Nanjing, 210036, China)(2. School of Civil Engineering, Southeast University Nanjing, 210096, China)(3. Fujian Academy of Building Research Co., Ltd. Fuzhou, 350108, China)(4. Fujian Provincial Key Laboratory of Green Building Technology Fuzhou, 350108, China)

AbstractTo explore seismic damage history from sound to collapse of reinforced concrete continuous bridge based on shaking table test, the collapse analysis of two-span continuous girder bridge model is carried out, and then a single collapse criterion is established at a structural level. Based on the key components of collapse, the overall evaluation index of seismic damage of the two-span continuous beam bridgeDis proposed, and the criteria for the classification and damage grades are presented. Numerical analysis results show that the energy ratio index proposed in this paper can effectively identify the time of earthquake damage and even the time of collapse. If the energy ratio is not more than the limit, the bridge will collapse. The middle pier and fixed bearing are the key components. It is proved that indexDproposed on the key components can assess the damage of the two-span continuous girder bridge model with different degrees. This evaluation system can also provide a reference for seismic damage assessment and seismic retrofitting of the same kind of bridges.

Keywordsreinforced concrete; continuous girder bridge; seismic damage recognition; collapse failure; evaluation

EngineFaultDiagnosisBasedonIndependentVariationalModeDecompositionandImprovedKernelExtremeLearningMachine

LIUMin，ZHANGYingtang，LIZhining，F(xiàn)ANHongbo

(Seventh Department,Army Engineering University Shijiazhuang, 050003, China)

AbstractIn order to extract effective fault features from the cylinder head vibration signal under strong noise background and classify faults, an engine fault diagnosis method of independent variational mode decomposition (IVMD) combined with improved kernel extreme learning machine is proposed. Firstly, the matching waveform is selected to carry out the end extension of the original signal according to the spectral cyclic coherence coefficient. And the signal after end extension is decomposed into a number of intrinsic mode functions (IMFs) by using variational mode decomposition (VMD). The end effect in VMD is suppressed effectively. Then the selected effective IMFs and original signal are constructed as the input observation signals of kernel independent component analysis (KICA). After KICA, the noise and effective signal are separated further, the mode mixing is eliminated and the independent effective fault feature bands are obtained. Autoregressive model parameters, multi-scale fuzzy entropy and normalized energy moment of each frequency band are extracted to construct a joint fault feature vector. Lastly the improved KELM model based on social emotional optimization algorithm (SEOA-KELM) is constructed to classify the fault features in order to realize the engine fault diagnosis. The simulation and experimental results show that the proposed method can effectively suppress the end effect in VMD, improve the signal decomposition precision, eliminate the noise，separate independent and effective fault feature frequency bands, enhance feature parameter identification and improve the speed and accuracy of engine fault diagnosis finally. The average accuracy rate of engine fault diagnosis is up to 99.85%.

Keywordsfault diagnosis; kernel extreme learning machine; social emotional optimization algorithm; spectral cyclic coherence coefficient; independent variational mode decomposition

BandgapPropertiesinSimplifiedModelofLocallyResonantPhononicCrystalCompositeDoublePanelStructure

QIANDenghui1,SHIZhiyu2

(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 simplified model of locally resonant phononic crystal composite double panel structure is proposed based on the widely researched locally resonant phononic crystal plates, and an improved plane wave expansion method is applied to calculate the structure. Numerical results and further analyses demonstrate that a complete band gap is opened in the low frequency region. The torsional spring, size and viscidity of soft material have obvious effects on the band gap, which cannot be influenced by the rotational inertia. All the results are expected to be of theoretic significances and engineering application prospects in the field of vibration and noise reduction.

Keywordssimplified model; phononic crystal double panel structure; improved plane wave expansion; bandgap property

DynamicStiffnessAnalysisandTestMethodofHighSpeedSpindleAngularContactBallBearing

YUNXialun1,2,3,MEIXuesong1,2,3,JIANGGedong1,2,3,LIYuting4,YUANShijue3

(1. Shaanxi Key Laboratory of Intelligent Robots, Xi′an Jiaotong University Xi′an, 710049, China)(2. State Key Laboratory for Manufacturing Systems Engineering, Xi′an Jiaotong University Xi′an, 710049, China)(3. School of Mechanical Engineering, Xi′an Jiaotong University Xi′an, 710049, China)(4. Luoyang Bearing Research Institute Co., Ltd. Luoyang, 471003, China)

AbstractIn order to test the dynamic support stiffness of angular contact ball bearings for high-speed electric spindle, a method for measuring the dynamic support stiffness of spindles by means of synchronous excitation is proposed. The dynamic support stiffness test principle is derived by studying the angular relationship between the residual vibration displacement and the excitation response displacement. The dynamic stiffness test is carried out on the electric spindle of the model 150SD40Q7, and the simulation results are compared and analyzed. The test and simulation results have the same trend with a small error. The validity of the test method is verified, which provides a reliable method for testing the dynamic stiffness of the spindle.

Keywordshigh speed electric spindle; angular contact ball bearing; dynamic stiffness; test principle