15 November 2018, Volume 37 Issue 23
    

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  • PING Huan1,ZHANG Kai1,2,ZHOU Dai1,3,4,BAO Yan1,ZHU Hongbo1,HAN Zhaolong1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 1-8.
    Abstract ( 356 ) Download PDF ( 189 )   Knowledge map   Save
    Both right cylinders and wavy ones’forced oscillations normal to incoming uniform flow under low Reynolds number (Re=150) were numerically investigated.The effects of oscillation amplitude and frequency on hydrodynamic forces exerted on these cylinders were examined.Their lock-in regions were determined and under lock-in states varying characteristics of lift force and wake were analyzed.The numerical simulation showed that although wavy cylinders can fully suppress Karman vortex street in static cases,the variation trend of their hydrodynamic forces with their oscillation frequency is similar to that of right cylinders under forced oscillation; wavy cylinders’suppressing lift and drag forces appear within lower and higher frequency regions,respectively; lift force curves have different performances under a lock-in state and a non-lock-in state; under a lock-in state,vortex modes in wake regions of right cylinders are controlled by oscillation frequency,2S and C(2S) modes are observed,while only one vortex mode is observed in wake regions of wavy cylinders.

  • WEN Baogang1,2,HAN Qingkai1,2,QIAO Liuchun1,2,ZHOU Xianwen1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 9-14.
    Abstract ( 284 ) Download PDF ( 193 )   Knowledge map   Save
    Cage clearances are an important parameter of ball bearings,and they directly affect cage’s force-bearing and motion,and even cage wear and bearing life.Here,based on analyzing the relation between cage clearance and its force-bearing,the effects of cage clearance on cage wear were qualitatively analyzed.Tests were conducted for these effects on a built ball bearing test rig.Under the same test conditions,tests were done for bearings with cages adopting different guiding clearances and pocket ones to analyze morphology wear features of cages and steel ball surfaces,and compare wear degrees of cages and steel ball surfaces under different cage clearances,and obtain the effect laws of cage clearance on its wear in an angular contact ball bearing.The test results showed that cage clearance significantly affects its pocket and guiding surface’s wear; increase in cage’s guiding clearance and pocket one can reduce wear degree of cage guiding surface; the study results provide a theoretical reference and a test basis for ball bearing’s cage clearance design and optimization.

  • MA Tianqi1, GU Jijun2, SUN Xu2,ZHANG Yingjin2,LI Mingjie3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 15-23.
    Abstract ( 255 ) Download PDF ( )   Knowledge map   Save
    The dynamic response of a riser conveying multi-phase flow under interaction between internal flow and external cross flow was analyzed.The internal multi-phase flow-riser-external cross flow coupled dynamic equations were established,and they were solved through transforming partial differential equations into ordinary ones with the generalized integral transform technique (GITT).The results showed that the internal two-phase flow causes the riser’s natural frequencies to drop; the higher the internal flow rate and the longer the length of the riser,the more significant the internal two-phase flow’s action; under the interaction of internal flow and external cross flow,increase in gas content inside the riser makes the frequency of the riser’s vortex induced vibration decrease and the vibration amplitudes increase; internal two-phase flow causes the riser’s resonance under a lower external flow rate and induces the riser’s higher order modal vibration; the higher the external cross flow rate,the smaller the action of internal two-phase flow.
  • GUO Wenjie2, LI Tianyun1,3,4,ZHU Xiang1,3,4,LIN Ziqin1,4
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 24-30.
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    Here,an acoustic scattering model of a finite long pulsating cylinder considering effects of free liquid surface was established,and an analytical method to solve the far-field sound pressure was proposed.Using the image method combined with Graf’s addition theorem,the expression for sound pressure in wavenumber domain was deduced.Then,the far-field sound pressure was derived using the stationary phase method.The study results showed that radiated sound and scattered one produce a dipole-like effect due to effects of free liquid surface; the far-field sound pressure’s directional sectioning increases with increase in immersion depth or frequency; the field point sound pressure periodically fluctuates with increase in immersion depth,while the scattering sound pressure fluctuates and decays; if frequency is low and immersion depth is larger than five times of cylinder radius,the mutual scattering effect can be neglected,this provides a reference for how to properly ignore the mutual scattering effect between target and interface within a limited space.
  • ZHOU Qicai, LIU Xingchen, ZHAO Jiong, SHEN Hehong, XIONG Xiaolei
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 31-37.
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    Aiming at problems of rotating machinery’s fault features needing to be extracted manually,complex fault recognition being difficult and diagnosis model’s poor robustness,a novel 1D depth convolutional neural network-based rotating machinery fault diagnosis model was proposed based on the classical convolution neural network model AlexNet.This new model adopted the modified 1D convolutional kernel and pool layers to adapt 1D time domain signals.The traditional intelligent diagnosis model included two distinct modules of manual feature extraction and classification,and the proposed model combined these two modules into one.With the proposed model,multiple alternate convolution and pool layers were used to complete learning the original signal’s self-adaptive features and then all connected layers were combined to realize fault diagnosis.Bearings and gearboxes health monitoring tests showed that the proposed model can realize accurate,stable and fast fault diagnosis; compared to BP neural network,SVM,1D-LeNet5 model and the classical AlexNet model,this new model is the best; the feature extraction effectiveness of the proposed model is verified with the PCA visualized analysis.
  • LI Hongxian, TANG Baoping, HAN Yan,DENG Lei
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 38-44.
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    Under a variable rotating speed condition,gear meshing can cover faulty bearing shock characteristics and make bearing fault characteristic information be weak.Aiming at effects of gear meshing on bearing fault diagnosis,a new method for variable rotating speed rolling bearing fault diagnosis based on the iterative generalized demodulation (IGD) gear signal separation was proposed.Firstly,The instantaneous dominant meshing multiply (IDMM) was extracted from the envelope time-frequency spectrum with the peak value searching algorithm to construct phase functions for various generalized demodulation functions with the IDMM trend line.Secondly,the gear meshing frequency and its frequency multiplication signals were separated from gear signals with the IGD algorithm,and residual signals were used to determine higher frequency resonance filtering parameters caused by faulty bearing with the spectral kurtosis algorithm and then bandpass filtering was done.Finally,the IDMM trend line extracted were taken as the bearing rotating frequency to perform angular domain resampling for filtered results.The order spectrum was used to judge rolling bearing’s operational state.The processed results of simulated signals and actual tested ones showed that the proposed method can be used to effectively realize time-varying rotating speed rolling bearing fault diagnosis without a tachometer.

  • XU Yang WANG Haohui SHENG Xiaowei
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 45-51.
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    A multi-layered equivalent finite element (FE) modeling method for honeycomb material was proposed to fast and accurately analyze honeycomb plates’mechanical properties.The calculated results of modal analysis,static analysis,and shock spectral analysis based on this model were compared with those using the current frequently-used FE modeling method.It was shown that the results using the multi-layered equivalent FE model agree better with performances of the original honeycomb plates; the proposed method can significantly improve calculation efficiency; based on the multi-layered equivalent FE model,complex parameters and target are quantified,and the function relation between honeycomb cell size and the first five order modal frequencies is established to provide a basis for structural optimization design.
  • JU Jinyong1,2,LI Wei1,FAN Mengbao1,WANG Yuqiao1,YANG Xuefeng1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 52-60.
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    It is an effective method to adopt a high-power alternating current (AC) permanent magnet motor to directly drive a scraper conveyer system,decrease its intermediate transmission links and achieve the aim of improving the system reliability and reducing its energy consumption.Here,a scraper conveyer driven by a permanent magnet motor was taken as a study object.Firstly,considering the torsional vibration instability of its main transmission system and its complex electro-mechanical coupled feature,the system’s global electro-mechanical coupled dynamic model was constructed with Lagrange-Maxwell equations.Then,Hopf bifurcation characteristics of the main transmission system under the action of a class of nonlinear friction damping were investigated and the system stable region was obtained with Hurwitz criterion.At the main transmission system’s instability boundary point,the center manifold theory was adopted to reduce the dimension of the system dynamic model,and the relationship between Hopf bifurcation type and nonlinear friction damping coefficient was deduced using the normative theory.The correctness of the theoretical analysis was verified with numerical simulation results.The study results provided a theoretical basis for the stable operation of scraper conveyers driven by permanent magnet motors.
  • DING Qinwei, HAO Wenxing, LI Chun, YE Kehua, WANG Yuanbo
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 61-70.
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    Studying stability of floating offshore wind turbines is a challenging problem in wind power field.Here,turbulence wind and irregular wave models with sharp fluctuations both in velocity and direction were established,respectively based on the turbulence wind spectrum and the wave one.An ITI Energy Barge platform floating wind turbine was taken as a study object.The stability control was conducted for the floating wind turbine with TMD equipped in its nacelle.Dynamic characteristics of the TMD floating wind turbine under the action of wind combined with wave were calculated based on the aerodynamic-hydrodynamic-servo-elastic simulation platform FAST.Furthermore,the multi-island genetic algorithm was used to optimize TMD structure parameters including mass,stiffness and damping.The results showed that the wind turbine nacelle equipped with TMD can realize the floating wind turbine’s stability control to obviously reduce amplitudes of platform sway and roll motions,and lateral displacement of platform tower top; lateral displacement of tower top and amplitude of platform roll firstly decrease and then increase with increase in TMD mass,while changes of TMD’s stiffness and damping have little effects on them; the TMD optimal structure parameters are mass of 21 393 kg,damping of 13 635 N/(m/s) and stiffness of 6 828 N/m; after equipped with the optimal TMD,the wind turbine rolling motion and its lateral displacement of tower top drop more obviously,their stabilities increase by 53% and 50%,respectively; the effectiveness and reliability of the proposed TMD control,optimization method and optimization results are verified with the calculation results; the study results can provide a reference for the stability study on offshore floating wind turbines.
  • JIN Chaochao1,2,3,ZHU Xiang1,2,3,LI Tianyun1,2,3,FANG Min1,2,3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 71-77.
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    The coupled vibration characteristics of a fluid-filled finite-length cylindrical shell with a circumferential surface crack were studied.Introducing a line spring model to simulate the circumferential surface crack in the classical thin shell theory,according to ideal fluid’s Helmholtz wave equation in cylindrical coordinates,applying the acoustic load of fluid on the shell based on the wave propagation method,and then the fluid-filled cylindrical shell’s coupled vibration control equation was built.The relationship between natural frequencies and axial wave-number of the cylindrical shell was solved with an optimal iterative method.Furthermore,the cylindrical shell’s natural frequencies were iteratively computed to satisfy the specific boundary condition and the continuity condition of crack position.The computation model was degenerated into 3 cases of a perfect cylindrical shell in vacuum,a cracked one in vacuum and a perfect fluid-filled one.The computation results of 3 cases were compared with those published in literature and calculated using the FEM,respectively.All results agreed well with each other to verify the correctness of the proposed method.Finally,the effects of crack depth and its position on the cylindrical shell’s natural frequencies were examined.
  • XIA Junzhong, WANG Zhi’an, CHEN Chengfa, L Qipeng, LIU Kunpeng
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 78-83.
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    Under varying speed condition,the conventional cyclic stationary method can’t effectively extract rolling bearing fault characteristics.Here,a rolling bearing fault feature extraction method based on the integrated order-frequency spectral correlation was proposed.Through studying the angle/time cycle stationary theory,it was shown that the order-frequency spectral correlation method can effectively extract rolling bearing fault characteristics under variable speed condition.The order-frequency spectral correlation estimation of discretized signals was realized using the cyclic modulation spectrum,and then a signal’s integrated order-frequency spectral correlation was calculated to extract bearing fault’s characteristic order.The analysis of simulation and test data showed that the integrated order-frequency spectral correlation can effectively extract rolling bearing fault characteristics under variable speed condition; it has a clearer and more intuitive expression effect compared to the order-frequency spectral correlation.

  • SI Qiaorui,SHENG Guochen,HENG Yaguang,CUI Qianglei,HUANG Kaile
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 84-90.
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    Based on Lighthill acoustic analogy theory,the interior acoustic field of a centrifugal pump was solved by using the method of CFD combined with the computational acoustics (CA).Firstly,the 3D unsteady computation was performed for the inner flow field in the centrifugal pump with the SST SAS turbulence model to deduce the acoustic source information,solve the acoustic field problem based on the results of the flow field computation,and compare advantages and disadvantages of BEM and FEM applied in this acoustic field problem.The results showed that the pressure fluctuation intensity near the volute tongues is the maximum and the sound pressure level is the highest; the blade passing frequency and its double-frequency is the main frequency of pressure fluctuation at each monitored point,the dynamic-static interaction between the impeller and volute tongues is the main cause of the centrifugal pump’s flow-induced noise; with increase in flow rate,the total sound pressure level gradually decreases to reach its minimum value at the operation case point with the highest efficiency and then increases; the more the deviation from the operation case point with the highest efficiency,the more obvious the wide-frequency band components; the acoustic FEM has  obvious advantages in predicting discretized noise,this method can comprehensively consider various acoustic sources of turbulent noise,and it is more advantageous to studying the inner flow field wide-frequency band noise problems.
  • LI Yong1,3,WANG Weining2,3,YAN Weiming3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 91-97.
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    Viscous dampers are installed on a lot of bridges located in high-intensity earthquake fortification zones for aseismic control.Their design and arrangement are always performed according to dynamic elastoplastic theoretical analysis and numerical simulation but they are lack of verification with shaking table tests,and practical engineering examples of bridges experiencing the test of earthquake are less.Here,porous type viscous dampers were designed and manufactured,and their hysteretic curves were measured through cyclic loading tests.Then these dampers were installed on a continuous girder bridge scale model to conduct shaking table tests to verify the bridge aseismic control effect.Test results showed that damping forces of viscous dampers increase with increase in loading frequency,and their measured hysteretic curves are close to an ellipse; viscous dampers have good aseismic control effects on the bridge’s fixed pier bottom strain,pier top displacement and longitudinal displacement of movable supports; there are different bridge aseismic rates under input of different earthquake waves,the maximum bridge aseismic rate can reach more than 50%.
  • ZHU Lingxue1,WANG Tongyin2,ZHU Xiaolei2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 98-103.
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    The energy absorption performance of a functionally graded lattice sandwich structure was studied based on gradient factor.The effects of face-sheet gradient factor and core one on the energy absorption performance of the graded structure were investigated,respectively using the FE simulation software ANSYS/LS-DYNA.The gradient factor was taken as the optimization variable and the surface specific energy absorption was taken as the optimization objective,the optimization of the graded structure was performed with the genetic algorithm.The results showed that changes of gradient factor affect the structure’s deformation mode; the influence of face-sheet gradient factor on the surface specific energy absorption is large; due to constraints of face-sheet structure on core deformation,the influence of the core graded factor is smaller; compared with non-graded structure,the energy absorption value of the graded structure after optimization increases by 100%; the results provide a guide for improving the blast resistance performance of lattice sandwich structures.

  • DANG Xuanju,PENG Huimin, JIANG Hui, WU Xiru
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 104-110.
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    Aiming at the direct instantaneous torque control system of a switched reluctance motor,a fuzzy fractional order PID control strategy was proposed here.Fractional integral and fractional differential were introduced into the two-dimensional fuzzy controller to design a fuzzy fractional order PID rotating speed outer loop controller.The fractional integral was used to improve the steady-state precision of the system and weaken the large overshoot caused by the integral saturation.The fractional differential was employed to overcome the shortcoming of the first order differential being easy to be disturbed by high-frequency interferences and improve the dynamic performance of the system.The PID torque inner loop controller was designed based on the RBF neural network to adapt to the nonlinearity of the switched reluctance motor,and realize the torque’s dual-closed loop tracking control.The simulation results showed that the proposed fuzzy fractional order PID rotating speed outer loop controller can effectively reduce the torque ripple of the switched reluctance motor to make the system quickly reach steady state with good dynamic performance and strong adaptability.

  • HUANG Mingfeng1, SUN Xuantao1, FENG He1, LOU Wenjuan1, HU Dejun2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 111-119.
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    The fluctuation of wind load on large-span lattice structures are complicated,usually need to be determined by wind tunnel tests.A new numerical simulation method for wind pressure fields of long-span lattice structures is proposed based on empirical wind pressure spectra and Hermite translation model.The proposed method is able to simulate the non-Gaussian wind pressure fields efficiently.The error control mechanism is carefully designed in the simulation method to effectively refine the simulation results with a calibration to the target non-Gaussian characteristics during the simulation process.The empirical wind pressure spectra are determined from the wind tunnel test results.Finally,the effectiveness and accuracy of the proposed method were demonstrated by comparing the numerical results of non-Gaussian wind pressure to the wind tunnel results both in time and frequency domains.
     
  • DIND Chuang, Zhang Bingzhi, FENG Fuzhou, WU Shoujun
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 120-125.
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    Aiming at the nonlinear and non-stationary vibration of planetary gearbox and the weak fault characteristic signal,the quantum theory was introduced into the calculation of information entropy,and a new feature extraction method,nonlinear quantum information entropy,was proposed.According to the basic concept of quantum theory,the multi-qubit system of vibration signal was established,the feasibility of introducing quantum theory into information entropy was analyzed,and the basic principle of nonlinear quantum information entropy was proposed.The nonlinear quantum information entropy of vibration simulation signals in three states of planetary gearbox was analyzed,and the feasibility of using quantum information entropy as the characteristic of planetary gearbox was illustrated.Finally,the nonlinear quantum information entropy of the five kinds of state signals collected by the planetary gearbox fault test bed was calculated and compared with the results of time-frequency entropy and sample entropy.The results show that nonlinear quantum information entropy can effectively extract the operating state characteristics of planetary gearbox.
  • LI Haotian,CHI Maoru,LIANG Shulin,WU Xingwen
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 126-132.
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    In order to solve problems of independent rotating wheels (IRWs) being lack of self-directed ability both on straight lines and large radius curves,and coupled wheel-pairs with a limit passing ability on small radius curves,the automobile differential principle was analyzed from the mechanical angle of tire-ground contact to introduce the applicability of mechanical differential and differential strategy of equal torque allocation applied in railway vehicles.Here,an IRW’s electrical differential control strategy was proposed,and a multi-body dynamic model of a light-rail vehicle with IRWs was built using the control strategy based on differential feedback.The IRW was modeled as an electrical differential controlled wheel-pair (EDCW).According to the vehicle’s motor’s characteristics,the key parameters of the control system were chosen to form a differential-based sliding mode control system using the platform of Simulink.Both models were coupled using the co-simulation module of SIMPACK and Simulink (SIMAT) to study the curve-passing ability of the vehicle with different control modes including the differential control mode and the equal speed control one.The results showed that when passing curves with small radius,the differential wheel-pair has a better curve-passing ability and its dynamic behavior is similar to that of IRW; when passing large-radius curves,the IRW with equal speed control mode has a better curve-passing ability,and its self-directed ability and dynamic behavior are similar to   those of coupled wheel-pair; when passing curves with medium radius,curve-passing abilities of IRWs with two different control modes are close to each other,and there is a cross and interchangeable curve radius’s demarcation zone,it is within 500-600 m.
  • QI Xiaoli, YE Xudan, CAI Jianglin, ZHENG Jinde, PAN Ziwei,ZHANG Xingquan
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 133-140.
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    A method for early fault diagnosis of rolling bearings based on the variational mode decomposition (VMD) combined with the local tangent space alignment (LTSA) algorithm was proposed.Firstly,the VMD algorithm was used to decompose vibration signals of a rolling bearing under different operational conditions,and several components most correlated to the original signal were screened out by solving the instantaneous frequency mean and plotting the feature curve.Then,the time domain index of the effective modal component and the frequency domain index formed with the wavelet packet frequency band decomposition energy were extracted.After these two indexes were combined to primarily extract higher dimensional fault features,LTSA was used to extract fault features again.Finally,the extracted fault features were inputted into a K-means classifier to recognize fault types.Through the contrastive test analysis of cylindrical roller bearings’fault diagnosis,it was shown that compared with the method of time frequency features extraction+LTSA and the method of EMD+LTSA,the method of VMD+LTSA has more advantages in classification effect and recognition accuracy; the LTSA algorithm has the best sensitivity to fault features after dimension reduction compared to the algorithms of PCA,LPP,LE,ISOMAP and LLE; the proposed method has a certain superiority in the fault diagnosis of cylindrical roller bearings.
  • CAO Feng1,2,3, LING Tonghua1, LI Jie4,HUANG Fu1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 141-148.
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    To study the effects of cyclic blast loading on shared rock in a neighborhood tunnel,taking Liuyuetian bifurcation tunnel as the engineering background,a 3D model of the bifurcation tunnel was constructed using the finite element software LS-DYNA.Based on the HJC constitutive model,the damage variable was introduced to simulate the cumulative damage evolution process of the remained rock in the neighborhood tunnel under cyclic blast loading,and explore the relation among shared rock’s damage degree,damage range and explosion number.According to the decay law of mass point vibration velocity in the damage zone,the relation among single blasting charge,the maximum damage range and the critical damage mass point peak vibration velocity was established through data fitting.Finally,the simulation results were compared with those of acoustic wave tests on site to verify the rationality and correctness of the numerical simulation results.The results showed that the numerical simulation results agree well with those of tests on site,and the maximum damage zone appears on arch shoulder of shared rock; compared with a single blasting,the cumulative damage range caused by cyclic blasting excavations increases obviously,while the critical damage mass point peak vibration velocity drops significantly.
  • FENG Lina LI Dong2 TIAN Jiandong1 SUN Jing1 WU Hanling1 CHEN Rong3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 149-156.
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    Separation structure is a key part of a space launch vehicle.The expanding tube separation device is widely used at the separating position of space launch vehicle.as a clean separation structure.Here,the finite element simulation analyses were performed for a flat tube assembly including flat tube,filler and explosive rope using the fluid-solid coupled algorithm in the software LS-DYNA and test verifications were conducted.The simulation results agreed well with those of tests.Furthermore,changing wall thickness of the flat tube,mass density and elastic modulus of filler,respectively,the variation laws of expanding velocity and expanding displacement of two feature points on the flat tube and the tube’s kinetic energy were analyzed through the finite element simulation to obtain the effects of these parameters on the flat tube’s deformation.The results provided a guide for the design of flat tube assemblies.
  • ZOU Xihong1,LIU Yu1,YUAN Dongmei2,CHEN Xuesong1, CHENG Kaihua1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 157-163.
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    Here,a multi-axial and multi-excitation test method was proposed,and an effective input method for virtual fatigue test of axle housing was provided.The finite element model of the axle housing was built,and its modal analysis and modal test were made.Their results agreed well with each other,the errors between first 5 order natural frequencies in modal analysis results and those in modal test were less than 5%,and the modal vibration shapes in both results were coincident.Then,using the modal synthesis method,the axle housing’s flexible body file was extracted.Using the finite element flexible body file replacement method,the axle housing’s multi-axial and multi-excitation rigid-flexible coupled virtual test system was developed,and the system was verified through simulation based on inputting simple harmonic signals and random signals.Based on a road’s simulated excitation spectrum,the axle housing’s virtual road simulation test was performed,and the multi-axial and multi-excitation virtual test system was used to conduct the test verification.The results showed that the simulated signals are in better agreement with the tested ones in amplitude and trend; the established multi-axial and multi-excitation virtual test system for axle housing has a higher correctness; the results provide an efficient and accurate means for the design verification and evaluation of axle housings.
  • LI Jing,HAN Zuoyue,ZHOU Yu,YU Chunxian
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 164-170.
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    Aiming at shortages in magneto-rheological (MR) dampers’present design procedure,constraint relations among design parameters were fully analyzed and the core design parameters were screened out.Dynamic constraint conditions were designed for the important design parameters in magnetic field.Based on the magnetic field finite element simulation results,a neural network was used to fit parameter boundary model,and narrow down the optimization range.The multi-parameter feedback whole vehicle control algorithm was designed based on the ceiling damping control idea and the parametric optimization was done.A joint simulation platform including whole vehicle model,controller model,damper model and actuator response model was established.Taking the vehicle body total weighted acceleration as the index,the genetic algorithm was used to globally optimize the MR damper’s design parameters.The results showed that the optimized damper can better meet the requirements of the suspension control; combined with the whole vehicle control algorithm,it can effectively improve vehicle riding comfort.
  • ZHANG Long1,2,3, MAO Zhide2, YANG Shixi1, LI Xinglin3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 171-179.
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    Kurtogram is an effective approach to determine the band-pass filter’s central frequency and band width parameters in the resonant demodulation method applied in rolling bearing fault diagnosis.In Kurtogram,a time domain signal’s Kurtosis value was taken as the filtering effect measure index,but this index was easy to be affected by non-Gaussian noise and occasional non-periodic impact,and cause wrong selection of filtering frequency band.Here,considering feature difference between the envelope spectrum of occasional impact and non-Gaussian noise and that of periodic impact,removing the influence of impacts caused by gear local fault and rotor rubbing,the middle segment of the filtered signal’s envelope spectrum was intercepted according to a certain rule,the Kurtosis of this segment envelope spectrum was proposed to measure the strength of periodic impact and called the band-pass envelope spectral kurtosis.The band-pass envelope spectral Kurtosis was employed to replace the filtered time domain signal’s Kurtosis and obtain an improved Kurtogram method.The effectiveness and advantages of the proposed method were verified with analyses of simulation signals and actual measured signals.
  • QIN Chaogang1,BAI Guoliang1,XU Yazhou1,SU Ningfen1,WU Tao2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 180-189.
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    Here,according to the similarity theory,similar relations of physical quantities in a dynamic system were deduced based on a mass system dimensions and appropriate similar constants were determined.A 12-story shear wall structure was disassembled,and its model material mix ratio and the model structure’s precast wall plates and connection technique were designed to construct a 1∶5 scaled monolithic precast concrete shear wall (MPCS) structure model and a cast-in-place shear wall (CIPS) one.The failure forms and dynamic characteristics of MPCS and CIPS structure models were contrastively studied with shaking table tests.The results showed that MPCS’s crack forms and their expansion sequence are different from those of CIPS; horizontal cracks in the upper and lower contact surfaces between precast wall plates are one of MPCS’s main damage forms; After connected beams’ends form a plastic hinge,final micro-cracks form at the vertical connection joint surface of MPCS precast wall plates,while those form at the wall limb of CIPS; the micro-cracks at connection contact surface between precast wall plates cause MPCS’s initial stiffness and main frequency to drop more obviously than CIPS’s do; structural damping ratios of both two models increase with increase in PGA,their variation range is 4.2 to 8.2%; the first order vibration shape curve of MPCS is approximated as a "bending" type and gradually becomes outward convex with increase in PGA,and that of CIPS becomes more obvious than MPCS’s does in plastic stage; the second order vibration shape curves of both two models are similar.
  • LIU Zhongsheng1,YANG Yang1,LI Chun1,2,ZOU Jinhua1,YUAN Quanyong1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 190-196.
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    The seismic dynamic simulation module for wind turbines was developed with self-programming based on the open-source code FAST and Wolf soil-structure interaction model.Compared with the Seismic Tool published in reference,the reliability of the established wind turbines’seismic dynamic simulation model was verified.The seismic dynamic responses of 3 wind turbines with different powers under 5 earthquake excitations were computed.The fractal and chaos theories were employed to analyse their seismic induced vibrations’nonlinear characteristics.The results showed that wind turbines’seismic induced nacelle vibrations have obvious nonstationary features,the wind-earthquake interaction effect must be considered for large-scale wind turbines; the fractal dimensions of seismic induced vibration acceleration time history curves are within a range of 1.6 to 1.8 with higher self-similarity and long-range correlations; for small wind turbines with weaker wind-earthquake interaction effect,there is a higher relevance between the vibration curves’fractal dimensions and earthquake intensity; obvious chaotic characteristics can be observed from seismic induced nacelle vibrations; the seismic induced vibrations are aperiodic and non-completely-random non-stationary vibration processes; for wind turbines with strong wind-earthquake interaction effect,there is a larger relevance between the maximum Lyapunov exponents of seismic induced vibration time history curves and earthquake intensity; the stronger the wind-earthquake interaction effect,the shorter the time length to predict vibration,and the stronger the vibration instability.
  • MA Chicheng1,2,LUO Yajun2,ZHANG Xinong2,CHENG Xiangmeng1,SHAO Mingyu1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 197-203.
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    Manipulators are usually designed to carry or move goods,and their mass may move or change its magnitudes in transmission,so manipulators belong to time-varying mass structures.Here,manipulators were simplified as flexible beam structures with time-varying mass to investigate their dynamic characteristics and vibration active control.The dynamic control equation of a flexible beam with time-varying mass was derived with the mode superposition method and the material constitutive equation.The transient responses of the system were computed,and its dynamic characteristics and vibration laws were analyzed.Then,vibration active control of this structure was studied.For the mass time-varying feature of the system,a fuzzy PID controller was designed to study vibration active control for this system.Vibration suppressions were simulated under different operational conditions,and the results were compared with those using a classical PID controller.Considering shortages of FFT in non-stationary signal analysis,the time-frequency analysis technique was utilized to decompose the collected vibration signals and obtain their energy distribution information in time-frequency domain.Hence,the control effects of the two controllers were compared more accurately.The numerical simulations showed that due to the system’s variable mass feature,the system doesn’t have natural frequencies,but has a resonance frequency band; both two control strategies of PID and fuzzy PID can realize the system’s vibration control,but the fuzzy PID controller has a stronger robustness and higher self-adaptability,so improving its parameters can effectively enhance the vibration control effect.
  • LI Chengcheng1,YUAN Xiaoming1,CAO Zhenzhong2,LI Ruishan1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 204-212.
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    Site liquefaction is a typical earthquake disaster,the most serious of which is liquefaction lateral displacement,and its zoning work is an important means to avoid and mitigate the disaster.The liquefaction lateral displacement zoning technology of NEHRP(National Earthquake Hazards Reduction Plan of US)represents the international advanced level at present,but it is a method based on single point lateral displacement formula and 2D GIS.Its reliability and accuracy depend heavily on high-density boreholes.Based on the essential requirement of seismic zoning and abandoning the point-surface zoning of NEHRP,a new method of liquefaction sideways zoning based on 3D GIS was proposed in this paper.By solving the key techniques of extracting surface elements such as the thickness of liquefaction lateral displacement layer and the content of fine-grained soil,the characteristic distribution of liquefiable soil layer was obtained,and combined with the criteria of liquefaction lateral displacement grade proposed previously,The zoning map of liquefaction lateral displacement suitable for small area and medium area could be given.By using the new method,the scale distribution of liquefaction lateral displacement in the south area of Tangshan under the M7.8 earthquake was obtained,which was in agreement with the aerial survey results after the 1976 Tangshan earthquake.It was shown that the new method is reasonable and feasible.This method overcomes the drawback of NEHRP method depending on high density borehole,ensures the accuracy of liquefaction lateral displacement zoning and greatly reduces the cost.
  • LI Yuxing, LI Yaan, CHEN Xiao, YU Jing
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 213-218.
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    In order to effectively extract frequency characteristics of ship-radiated noise,a novel feature extraction method for ship-radiated noise was proposed based on the variational mode decomposition (VMD) and center frequency.Firstly,three types of ship-radiated noise were decomposed into a set of intrinsic mode functions (IMFs) with limited bandwidth using VMD,respectively and then the intensity of each IMF was calculated.IMFs with higher energy were selected as study objects,the central frequency of the strongest IMF and central frequencies of several IMFs with higher energy were taken as feature parameters to conduct feature extraction for three types of ship-radiated noise.Aiming at problems of frequency feature extraction of ship-radiated noise being difficult and inaccurate,the VMD method could be used to accurately extract the central frequency of IMF,and realize the feature extraction of ship-radiated noise.The proposed method was applied in feature extractions of simulated and actual signals of ship-radiated noise.The results were compared with those using the central frequency method and the difference between higher frequency energy and lower frequency energy method based on EEMD.The results showed that the proposed method can be used to effectively extract the central frequency of ship-radiated noise and realize the classification and recognition for different types of ships.

  • LI Hua,WU Xing,LIU Tao,CHEN Qing
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 219-225.
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    Aiming at problems of the variational mode decomposition (VMD)’s parameters needing to be determined in advance and how to choose intrinsic mode functions (IMFs) containing fault feature information,a method to determine VMD parameters and the other one to choose IMFs both based on information entropy were proposed.With these methods,the original fault signal was decomposed using VMD,and the VMD parameters were optimized with the minimum information entropy principle to obtain several IMFs.The IMF corresponding to the minimum information entropy was chosen as the effective IMF to do the envelope demodulation analysis,and extract a bearing fault feature frequency.Through analyzing bearing simulated signals and actual signals,it was shown that the proposed methods can be used to effectively extract weak features of the early fault signal of a rolling bearing,and realize accurate fault diagnosis.
  • ZHANG Yuping, WANG Hao, ZOU Zhongqin, TAO Tianyou, ZHENG Wenzhi
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 226-233.
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    A long-span triple-tower suspension bridge is a brand-new type of multi-tower suspension bridge structure with super span ability,and its aseismic behavior attracts extensive attention.Elastic-plastic steel damper (EPSD) is widely used in seismic reinforcement of building structures,but its application in bridge engineering is rare.Here,taking Taizhou Bridge in China as an example,EPSD applied in aseismic control of a long-span triple-tower suspension bridge was studied.Firstly,the sensitivity analysis was performed for EPSD’s parameters to acquire the optimal control parameters.Then,vibration control effects were studied based on two different seismic input modes including uniform excitation and traveling wave excitation,and influences of seismic apparent wave velocities on the aseismic effect were emphatically analyzed.The results showed that relative displacements between towers and the main girder can be effectively reduced with the application of EPSD,but shear force at the bottom of mid-tower and internal forces at the bottom of edge towers under several apparent velocities increase; the internal force aseismic effects on the structure end close to the earthquake source are better than those far from the earthquake source under a certain range of low apparent wave velocities,while the aseismic control effects on the structure end far from the earthquake source are significantly better than those close to the earthquake source under high apparent velocities.
  • ZHANG Yongchang1, XU Yugong2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 234-240.
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    Grille-cavity flow can cause flow field self-excited oscillations to lead to various engineering problems.Here,wind tunnel tests were used to investigate spatial distribution characteristics of flow field oscillations.A grille-cavity test device was built.Using the time-resolved particle image velocity (TR-PIV) measurement system,velocity fields of the cavity’s sections in different spread directions were measured.The time-frequency characteristics of velocity oscillations at the specific positions of flow flied were analyzed.The results showed that in grille-cavity flow,the flow field self-excited oscillation frequencies are uniformly distributed in space and their Strouhal number is about 0.37; on the outside of the grille,the oscillation amplitudes have a variation of increase-decrease-increase in flow direction; on the inside of the grille,the oscillation amplitudes increase firstly and then decrease; the oscillation amplitudes are symmetrically distributed along the spread direction to reach the maximum on the spread bisector plane,and the minimum on the cavity’s wall surface.
  • ZHAO Paihang,WANG Ruilin,LI Yongjian,JIA Yunfei,KANG Xiaoyong
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 241-246.
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    In order to study effects of rubber cushion on launch performance of a sniper grenade launcher,the constitutive models of the rubber buffer under static load and different average strain rates were studied with static and dynamic loading tests to construct the whole weapon system’s dynamic simulation model.According to the simulation results,the motion curves of automata,cartridge and guide rail were analyzed.These motion curves and the recoil one with or without a cushion were contrastively analyzed.The results showed that the constitutive model of rubber material has obvious nonlinearity,hysteresis and strain rate effect; the material strength gradually increases with increase in strain rate; the buffer action of the rubber cushion can effectively reduce influence of rigid contact on the system and the recoil amplitude; the rubber buffer effectively improves the system stability and ergonomics.The study laid a good foundation for further improvement of this type weapon system.

  • SHAN Wentao,WANG Xin
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 247-252.
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    Aiming at the problem of stator current oscillation appearing with increase in rotating speed in a surface mounted permanent magnet synchronous spindle (PMSS)’s flux-weakened control,based on analyzing the flux-weakened control algorithm and the rotating speed regulator,an improved leading angle flux-weakened rotating speed regulation strategy based on the fuzzy control was proposed.With this strategy,the improved leading angle flux-weakened control algorithm was used to extend the spindle’s rotating speed regulation range and suppress current oscillation.A fuzzy PI rotating speed regulator was used to realize the parametric dynamic adjustment and improve the system’s stability.The actual test results showed that the improved fuzzy control-based leading angle flux-weakened control strategy can effectively suppress the stator current oscillation to improve the PMSS’s dynamic performance and stability.

  • GAO Guangyun1, DAI Yibo1, LEI Dan2, YANG Chengbin3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 253-260.
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    To study environmental vibration of pile-net composite subgrade under high speed train dynamic load,a 3D track-embankment-pile-net composite subgrade model containing cushions,pile caps and pile bodies was established based on the finite element software ABAQUS.Firstly,a certain segment of pile-net composite subgrade on the east side of Suzhou station in Beijing-Shanghai high-speed railway was taken as the background to build the model,and the simulated ground vibration results were compared with the actual measured results to verify the reliability of the proposed numerical model method.Then,the influences of train speed,embankment height and soil damping ratio on ground environment vibrations of high-speed railway composite subgrade were analyzed.The results showed that at the place near track center,the resonance condition between train speed and roadbed soil determines the intensity of ground vibration; at the place far from track center,train speed mainly determines ground vibration; the higher the embankment height,the larger the reinforcement range in the composite subgrade,the larger the vibration reduction caused by the dynamic load of the train,it is due to cushions and piles transmitting vibration waves into the bottom of subgrade; soil damping ratio determines ground vibration at the place far from subgrade,the larger the soil damping ratio,the faster the attenuation of ground vibration with distance,so it is necessary to reasonably determine soil damping ratio.
  • CHEN Weilin, JI Chunning, XU Dong
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 261-269.
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    Numerical simulations for vortex-induced vibrations (VIVs) of two tandem cylinders with small spacing ratios of L*=1.1—1.5 were performed,where Reynolds number Re=100,the reduced flow velocity Ur=3—30 and the mass ratio m*=2.0.Two cylinders only have transverse vibrations to keep the distance between them unchanged.The simulated results showed that there are three types of vibration responses; when L*≤1.1,the responses exist in reduced flow velocity’s a larger range of Ur=4—28; when L*=1.2—1.3,wake relaxation vibration similar to VIV at high Re number appears under large reduced flow velocity; when L*≥1.5,the vibration responses increase and reach the maximum with increase in reduced flow velocity,and then they decrease slowly and finally have a steady large value; the upstream and downstream cylinders’hydrodynamic forces have different changes for different types of vibration responses; the mean drag values of downstream cylinder are obviously lower than those of upstream cylinder due to the shielding effect of upstream cylinder; in the area where wake relaxation vibration appearing,the lift force’s mean square root values of two cylinders increase with increase in reduced flow velocity; the unsteady interactions between cylinders under some reduced flow velocities are revealed.
  • CHEN Weilin, JI Chunning, XU Dong
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 270-277.
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    A detailed investigation was performed for VIVs of two tandem cylinders to analyze wake flow and interaction mechanism.The results showed that when L*=1.1—1.3,the classical Karman vortex street exists at small reduced flow velocities,while wake flow gets confused at larger reduced flow velocities; when L*=1.5,wake flows are regular 2S modes; when L*=1.1,the variation of equilibrium position difference of two tandem cylinders makes vibration responses exist under wider reduced flow velocities; when L*=1.2—1.3,the unsteady interactions with multi-frequency components participated induce quasi-wake relaxation vibration appearing; when L*=1.1,the low pressure region produced by shedding vortex of upstream cylinder and low-frequency motion of downstream cylinder are the dynamic sources to sustain large amplitude vibration responses; when L*=1.1 and Ur=15,a new intermittent jumping phenomenon of equilibrium position of two cylinders occurs,and the response can last longer time at the new equilibrium position on upper side.
  • CHEN Gaohua1,YAN Xianguo2,GUO Hong2,LI Zhifei1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 278-285.
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    The hysteresis nonlinearity of piezoelectric ceramic sensors affects detection accuracy in vibration measurement.Here,the micro-polarization mechanism of piezoelectric ceramics was analyzed and the reason why piezoelectric ceramic sensors have hysteresis nonlinearity was explained.In order to effectively compensate the hysteresis nonlinearity of piezoelectric ceramics and improve the detection accuracy,a modified Bouc-Wen model to reflect the asymmetric hysteresis feature of piezoelectric ceramic sensors was proposed.The effects of model parameters on magnitude,shape and stationarity of hysteresis curves were analyzed.The solving method of the inverse model was derived.The modified Bouc-Wen inverse model was taken as a compensator to compensate the hysteresis nonlinearity of piezoelectric ceramic sensors.The test results showed that after using the inverse compensation,the corrected displacement can always track the actual input displacement of the sensor to effectively guarantee its detection accuracy.
  • DONG Jie1,2,WU Zhihui1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 286-291.
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    To further study vibration propagation induced by the heavy-haul train in the seasonally frozen area,this paper examines the world’s largest heavy-freight railway-the Daqin Railway.The vibration accelerations of the embankment and foundation under the operation of the trains are measured during summer、autumn and winter.It is shown that with increasing axle weight and train speed,the peak and mean values of the acceleration increased.When the horizontal distance between the measuring point and the shoulder increases,the acceleration characteristic value decays rapidly.The vibration acceleration attenuated the most from the shoulder to the embankment footing,and the vibration attenuation trend is slowing down when the distance is 5 m away from the shoulder.The increase of train speed will increase the vibration amplitude,but when the vehicle speed increases to about 90 km/h,the change of speed has less influence on the vibration acceleration amplitude.The water content of soil layer in summer and autumn has little effect on surface vibration.The presence of surface frozen soil layer increases the overall stiffness of the embankment and the site,and the acceleration is 10%—26% greater than that of the unfrozen period with the wider acceleration spectrum and high-frequency components.
  • FANG Saiyin1,2,QIU Rongzu1, LI Ming2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(23): 292-298.
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    In the traditional empirical mode decomposition (EMD) algorithm,the upper and lower envelopes fitted using the cubic spline interpolation may have overshoots and error propagation.Here,an improved piecewise cubic Hermite interpolation (IPCHI) algorithm was proposed to replace the cubic spline interpolation according to the extreme value feature of all interpolating nodes in EMD.The improved EMD algorithm was used to analyze wood acoustic emission (AE) signals.Firstly,the wood AE signals were acquired with wood three-point bending tests.Then,an eight-layer wavelet was used to reduce noise of the original wood AE signals.Afterward,the de-noised AE signals were decomposed using the improved EMD.The principal intrinsic mode function (IMF) was determined with the correlation principle,and the frequency distribution of the principal IMF was used to determine the feature frequency range of the wood AE signals.Finally,the instantaneous frequency was used to judge the wood AE events and do their statistics.The test results showed that the combined method of wavelet and EMD can obviously improve the feature analysis effect of the wood AE signals,and judging wood AE events according to instantaneous frequency has more definite physical significance.