28 February 2018, Volume 37 Issue 6
    

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  • ZHAO Yaobing 1, JIN Bo 2, HUANG Chaohui 1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 1-6.
    Abstract ( 332 ) Download PDF ( 115 )   Knowledge map   Save
    A new thermal stressed configuration of suspended cables was generated under the effects of temperature variations which lead to some changes of the cable tension force and sag. The effects of temperature changes on the nonlinear equations of motion of a suspended cable are reflected by two nondimensional factors related to the cable tension and sag. On the basis of the nonlinear inplane vibration equations of the suspended cable under harmonic excitation where the temperature effects were taken into consideration, the Galerkin method was introduced to discretize the nonlinear partial differential equations firstly, then the multiple scales method was used to obtain the approximate solutions of 1/2 and 1/3 order subharmonic resonances, and the corresponding frequency response equations were obtained. Furthermore, the temperature effects on the resonance responses were investigated quantitatively and qualitatively by using numerical examples. The numerical results show that the effects of different temperature variations on the subharmonic resonances of the suspended cable are obvious, and these effects are closely related to the sagtospan ratio. As to the case of small sagtospan ratio, the nonlinear vibration characteristics would be varied by the temperature effects quantitatively and qualitatively, and the deflection and its degree of the frequency response curves are changed under the temperature effects, and the range of resonances and the response amplitudes are also affected. As to the case of large sagtospan ratio, only some quantitatively changes are induced by the temperature variations, and the response amplitudes are altered. Due to the initial tension force, the effects of warming and cooling on the nonlinear subharmonic vibration behaviors of the suspended cable are not symmetric.
  • WANG Gang1, CHEN Jie1,2, HONG Rong-jing1,2, WANG Hua1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 7-13.
    Abstract ( 298 ) Download PDF ( 208 )   Knowledge map   Save
    A novel prediction approach for NC rotary tables was proposed based on the hidden Markov model(HMM) and the particle filtering(PF) to estimate the degradation trend of the replicated positional accuracy. The initial parameter of particle filtering was optimized by the particle swarm optimization(PSO). The vibration signal was selected as the data for research, which was obtained from an accelerated accuracy degradation test of a NC rotary table. The original signal was denoised and reconstructed by an ensemble empirical mode decomposition and principal component analysis. Then, a HMM was trained by an observation matrix which was composed of the statistical characteristic values, and the diagnosis of early positional accuracy degradation and the health status indicators of the accuracy were obtained. Finally, the degradation trend model of the positional accuracy was established by the particle filtering, and the residual accuracy life was calculated.When fiftieth sets of data were used as the starting point of prediction, the predicted residual life is 21, and the actual measurement result is 17, which are close to each other. Comparing the results of model calculations and experimental measurements, it is shown that the approach is efficient to estimate the degradation trend of the positional accuracy and the residual accuracy life.
  • YANG Qianqian,LIU Lilan
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 14-20.
    Abstract ( 253 ) Download PDF ( 759 )   Knowledge map   Save
    The advancement of microelectronics reduces the power of sensors, making it possible to use the ambient vibration to selfsupply the sensors. The mechanical model of a bistable piezoelectric cantilever beam power generation system considering the gravity influence was established, and a dimensionless control equation of the system was obtained. By means of numerical analysis, the influence of gravity on the average output power of the bistable piezoelectric cantilever beam was investigated under the combined excitation of simple harmonic wave and white noise. Combining with the halfpower bandwidth method, the method of determining the minimum influence interval of gravity under white noise excitation was put forward under the premise of ensuring the high power output of the piezoelectric power generation system. The above results can provide  references for the related research of piezoelectric power generation systems.
  • YANG Yongbao1,WEI Yintao1,LI Xuebing1,ZHANG Xinyue2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 21-27.
    Abstract ( 315 ) Download PDF ( 179 )   Knowledge map   Save
    Based on the DonnellMushtari shell theory, exact solutions to the free vibration frequency of a thinwalled cylindrical shell subjected to radial prepressure with elastic foundations at both ends were presented, and there is little difference between the results by this method and those available in the literature. With the free vibration frequency and modal shapes of the thinwalled cylindrical shell obtained by using this method, the formulas for forced vibration steadystate responses were developed. The influence of modal numbers and damping factor on steadystate responses of the thinwalled cylindrical shell has also been investigated. The results and conclusions of numerical examples can provide references for engineering applications.
     
  • LIU Zhihao1,GAO Qinhe1,LIU Zhun1, WANG Xu1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 28-35.
    Abstract ( 299 ) Download PDF ( 21082 )   Knowledge map   Save
    The experimental modal analysis, dynamic modeling and structural parameter identification were employed to research the inplane vibration modes of heavyloaded radial tires with larger flat ratio. The coupled characteristics of flexible tread, distributed sidewall element and rim were investigated by means of the experimental modal analysis. Taking the bending and inflation features of the flexible tread and the inertial force and sectional spring of the sidewall into consideration, the coupled kinematics of flexible tread, distributed sidewall element and rim was modeled. The inplane coupled analytical modal frequency was derived. The structural parameters identification was implemented and the higher order modal frequenies were predicted with the analytic method. The results show that: the flexible tread vibrates in the same/opposite direction with the distributed sidewall within 0-180 Hz and 180-300 Hz respectively ; the modal analysis and kinetics modeling in consideration of the coupled features of flexible tread, distributed sidewall element and rim can accurately characterize the inplane vibration features of heavy loaded tires within the frequency band of 300 Hz. 
  • CHAI Kai1,ZHU Shijian2,YANG Qingchao2,LIU Shuyong1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 36-41.
    Abstract ( 245 ) Download PDF ( 171 )   Knowledge map   Save
    A trimagnet vibration isolator was proposed for the purpose of lowfrequency vibration isolation of submarine mechanical equipments. The analytical magnetic force and stiffness models were established based on the equivalent charge method and the structure parameters of the rectangular magnet were optimized. A trimagnet vibration isolator with the rectangular permanent magnets was proposed. The approximate expression of the magnetic stiffness was obtained through curve fitting. The dynamic equation of the vibration isolation system was built, the first approximation of the primary resonance was achieved with the harmonic balance method, and the effects on the force transmissibility caused by the excitation amplitude and damping ratio were discussed. A trimagnet vibration isolator test rig was designed, and experiments were carried out to evaluate the force transmissibility under excitations with different frequency, and to compare with those of the corresponding linear vibration isolator.The results show that the trimagnet vibration isolator with the characteristics of highstaticlowdynamicstiffness and smaller peaks of resonance, can provide a novel approach for the lowfrequency vibration isolation of submarine mechanical equipments.
  • GUAN Guang?feng, XIONG Wei, WANG Haitao
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 42-46.
    Abstract ( 213 ) Download PDF ( 118 )   Knowledge map   Save
    The redundant actuation is favorable to spread the load of electrohydraulic shaking tables and improve the performance indices of evenness and transverse component of acceleration signals. The redundantly actuated electrohydraulic shaking table is a new prospect for vibration test systems and the corresponding control system is the key technology of multiaxis electrohydraulic shaking tables. A kinematics analysis was presented to transform signals between the joint space and work space, and an acceleration control loop was developed based on the kinematics analysis and the control precision was improved when actuator strokes are relatively large. An inner force control loop was designed based on the dynamic analysis of the shaking table to reduce the cross coupling among the actuators. The constant attitude test, step response and acceleration amplitude frequency response characteristics analysis and sine vibration test were used to verify the effectiveness of the proposed control method.
     
     
  • XUE Jianyang,BAI Fuyu,ZHANG Xicheng,SUI Yan,ZHOU Chaofeng
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 47-54.
    Abstract ( 292 ) Download PDF ( 134 )   Knowledge map   Save
    Based on the shaking table test of a singlebay ancient timber frame with a scale ratio 1∶3.52, the damage rules for the initial stiffness and yield stiffness of mortisetenon were obtained under cumulative earthquake action. The structural simplified mechanics model was established, the relationship between the stiffness of the structure and the stiffness of the mortise joint was established by means of the static and dynamic cohesion method, and the structural state equation and observation equation were deduced. The responses of displacement, velocity and acceleration were obtained by the force hammer percussion test and simulation calculation. Considering the 5% noise disturbance in the laboratory environment, the damage identification was carried out by the least squares method and the extended Kalman filter method. Based on the identification results, the damage values of the initial stiffness and yield stiffness were calculated. The results show that the initial stiffness damage of mortisetenon joints increases first and then decreases, the yield stiffness damage is straightly increased, and the hybrid algorithm has higher precision for identifying the initial stiffness and yield stiffness.
     
     
  • PU Qianhui1,HONG Yu1,WANG Gaoxin2,LI Xiaobin1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 55-60.
    Abstract ( 324 ) Download PDF ( 2497 )   Knowledge map   Save
    The proposed fast eigensystem realization algorithm (FERA) is an improvement of the ERA, which can improve the calculation efficiency and cut down the data storage. To avoid the singular value decomposition of Hankel matrix, the eigenvalue decomposition of a newly built symmetric matrix was adopted in the method. Asimulated fourstory frame structure was utilized for validating the accuracy and efficiency of the FERA method. The scaled El Centro earthquake was applied to the structure as an unknown excitation. Both FERA and ERA methods were used for extracting the modal parameters from the simulated displacements, velocities and accelerations, respectively. After comparing the modal analysis results with the analytical values, the conclusions show that the FERA can accurately identify modal parameters from any type of dynamic responses, and the computational speed can increase rapidly. In addition, the FERA was used for extracting modal parameters of an inservice pedestrian bridge through ambient test, and the results show that the proposed method can also work for the actual structure.
  • LI Junliang1.2 TENG Kenan1 XIA Fei2.3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 61-67.
    Abstract ( 293 ) Download PDF ( 223 )   Knowledge map   Save
    Military aircraft state monitoring data have the characteristics of multidimensionality, nonlinearity and strong coupling, and monitoring data samples are of large capacity with high updating rate. So, existing state prediction models are difficult to meet the engineering requirements of high precision and realtime performance. How to predict military aircraft status informations accurately and fast is a difficult problem which needs to be settled. The paper uses the deep belief learning theory and simulated annealing algorithm to present a state prediction model for military aircraft key components. The research process consists of three stages: choosing monitoring parameters of the aircraft key components under different mission profile in order to design network samples; developing a deep learning network and prediction model; validating the model with testing date. Lastly, an aircraft engine was employed to demonstrate the efficacy of the proposed approach. The predicted results were compared with those by the SVM and ELMAN. It is found that the average error between the predicted and the measured values based on the proposed approach is less than 0.04, much smaller than that of the SVM and ELMAN method, and its running time is shorter than the above two methods, which proves the feasibility and effectiveness of the proposed approach.
  • LI Xiongyan1,SHAN Mingyue1,XUE Suduo1,HUANG Fuyun2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 68-75.
    Abstract ( 260 ) Download PDF ( 153 )   Knowledge map   Save
    In order to investigate the effect of the FPS bearing in largespan latticed shell and the influences of spatial variation of ground motions on the isolated structure, the shaking table test of a singlelayer cylindrical latticed shell shrunk model with FPS base isolation under multisupport excitations was designed and conducted. Small amplitude sinusoidal waves and 3 natural earthquake records with different frequency spectrum were chose, of various intensities, dimensions and visual wave velocities, to input into the model. The dynamic characteristic with/without FRS bearing, and the dynamic responses such as displacement, acceleration and strain were examined. Mechanical characteristics of the FPS bearing were derived by quasistatic test. The results show that FPS could prolong the natural vibration period of isolated latticed shell efficiently. The latticed shell roof tends to rigidbody motion and the horizontal earthquake actions of the upper structure reduce 1 to 2 degrees due to the installation of the FPS bearings. The effect of FPS base isolation is obvious. Under wavepassage excitation, the structural responses tend to be enlarged along the wave propagative direction and the roof rotates horizontal slightly.
  • LI Qian1,LIU Junqing2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 76-81.
    Abstract ( 212 ) Download PDF ( 453 )   Knowledge map   Save
    In order to figure out the asphalt pavement evenness deterioration mechanism, an evenness deterioration model considering the vehiclepavement interaction was established based on the Shell’s permanent deformation theory.Then a complete Matlab program was developed to solve the equations. The permanent deformation of a test road was calculated after opening to traffic for one year,  and the result was compared with the measured value. The error is only 9.7%, which verifies the reliability of the proposed model. The mechanism of the asphalt pavement evenness deterioration and the influencing factors of the deterioration were analyzed based on the model. The results show that the random dynamic loading by vehicles causes the difference of the accumulation rate of the pavement permanent deformation along the longitudinal direction. With the increase of the times of axle loading, the difference increases, which will lead to the pavement evenness deterioration. The deterioration in turn will aggravate the dynamic loading, thus forming a vicious circle. The pavement evenness deteriorates nonlinearly with the increase of axle loading times. The smaller the vehicle speed and the bigger the axle load, the faster the pavement evenness detorioration with time, which means more unfavorable to the pavement.

  • L Juanxia1,CAI Guoping1,PENG Fujun2,ZHANG Hua2,L Liangliang2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 82-85.
    Abstract ( 242 ) Download PDF ( 209 )   Knowledge map   Save
    The eigensystem realization algorithm (ERA) was used to identify the modal parameters of a membrane antenna system. The configuration of the membrane system and then the basic theory of ERA were introduced. The modal parameters of a flexible beam and the membrane antenna system were identified by the ERA. The simulation results indicate that the ERA is effective to identify the lowerorder natural frequencies and modal shapes of the membrane antenna system.
     
  • LI Ya’nan,HAO Zhiyong,ZHENG Xu,YANG Wenying
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 86-91.
    Abstract ( 296 ) Download PDF ( 524 )   Knowledge map   Save
    Aiming at reducing the abnormal noise of a certain vehicle, the excitation source was searched and determined by experiments. Besides, the mechanism of the noise caused by torsional vibration was analyzed. The influences of the rubber torsional stiffness and the MOI (moment of inertia) of the ring on the TVD (torsional vibration damper) modulation effect were studied respectively and their influential extents were compared. The conclusions are drawn that changing the MOI of the ring and torsional stiffness of the rubber can reduce the amplitudes of high harmonic components in the common speed region, however their influential extents are different. Based on the conclusions, the optimization to the original TVD was carried out. With the optimized TVD, the abnormal noise reduces greatly both in test and subjective assessment, and reaches the acceptable level.
     
     
  • WEN Jing,ZHANG Minzi,ZHANG Heng
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 92-98.
    Abstract ( 190 ) Download PDF ( 225 )   Knowledge map   Save
    The existence of 90° bend has a negative impact on the performance of pipeline leak dectection and location. For metal pipelines, the leaking pipeline model and 90° bend model were taken as investigated as objects based on the ANSYS simulation software for calculating and analysing the piping flowinduced vibration. And a 90° bend noise suppression method, combining the empirical mode decomposition(EMD) with the sample entropy, was proposed to wipe out the bend noise included in the leakage signal and to improve the accuracy of leak detection positioning. The simulation and experimental results show that the method proposed is suitable for the bend noise suppression .

  • ZHOU Qizheng,ZHAO Yang,WANG Deshi
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 99-103.
    Abstract ( 188 ) Download PDF ( 249 )   Knowledge map   Save
    In order to investigate the vibration characteristics of barrels during the artillery continuous firing, the transverse vibration equation of a barrel under the acceleration impact of projectile was established. The series analytical solution of the barrel under the impact of single projectile was given by employing the small parameter method. Then the solution of the artillery continuous firing was derived by iterative method. For the projectiles with and without massunbalance, considering the acceleration of the projectile tested, the vibration characteristics of the barrel were analyzed with different launching intervals. The results show that the decay rate of the impact response is affected by the damping coefficient of the barrel. The muzzle vibration amplitude without launching intervals is larger, and the shooting accuracy is decreased. For a given barrel, the muzzle vibration amplitude under continuous firing is the same as the single firing’s when the launching interval is large enough. The results are available for determining the firing speed and improving the shooting accuracy.

     
  • ZHU Xiaoyan,WANG Yongjie
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 104-110.
    Abstract ( 427 ) Download PDF ( 281 )   Knowledge map   Save
    The original impulse components in rolling bearing incipient fault signals are difficult to be extracted since they are always covered by strong noise. Aiming at this problem, a new fault diagnosis method for rolling bearing incipient faults based on the multipoint optimal minimum entropy deconvolution adjusted (MOMEDA) and Teager energy operator was proposed. Firstly, an original fault signal was filtered by MOMEDA then the Teager energy operator was used to enhance the deconvolution signal. Finally, in order to find the fault frequency, the envelope analysis was employed to deal with the processed signal. The fault location of the rolling bearing was extracted by contrasting the major frequency with the fault frequency of the rolling bearing, therefore, the fault type of the rolling bearing was confirmed. The analysis results of simulated signals and measured signals show that the proposed method is able to extract fault impulse signals and it is kind to practicability.
     
  • WANG Xiang,JIN Dongping
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 111-123.
    Abstract ( 230 ) Download PDF ( 200 )   Knowledge map   Save
    Large space hoop structures are often simplified as space beams and circular rings to analytically investigate their thermally induced vibrations. For analysing the thermally induced vibration of hooptruss structures used to support the antenna reflector, a coupled thermalstructural model for the space circular ring was developed. Its approximate solution was derived by the weighted residual method, based on that the simplified system equation in state space was established. The stable region of the thermally induced vibration considering the effects of the incident angle of solar radiation and the structural damping was obtained by RouthHurwitz criterion. Finally, using an analysis method combining the Fourier thermal finite element and the structural finite element, the dynamic responses subjected to thermal shock were simulated numerically and the results were verified for different cases.

  • LV Yuanzheng,XIA Guodong,CHEN Yongchang
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 117-123.
    Abstract ( 211 ) Download PDF ( 230 )   Knowledge map   Save
    The heat transfer performances of the microjets array impingement were studied by numerical simulations. After validating the model, the effects of rectangular pulses were analyzed on heat transfer characteristics by adjusting the pulse parameters. Then, some reasons for using rectangular pulse jets to enhance the heat transfer were discussed by flow field analysis. All of the simulations show that, if the duty ratio of the pulses is 0.5, the heat transfer characteristics of the microjet array will be effectively enhanced when the meantime Reynolds number is increasing. The enhancement of heat transfer by the adjustment of frequency is highly dependent on the flow regime of the jets. In the proper frequency band, the heat transfer coefficient of turbulence flow can increase by 20%, and the coefficient of laminar flow can increase by 7.5%. Under rational conditions, rectangular pulses jets can strengthen the impact effects and the disturbance of vortex in the cavity, therefore, the microjet array can obtain better heat transfer performance.

  • DING Xun1, ZHOU Ding1, LIU Duo2, ZHANG Jiandong2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 124-129.
    Abstract ( 228 ) Download PDF ( 178 )   Knowledge map   Save
    The free vibration characteristics of simply supported stiffened rectangular plates strengthened with pretension CFRP sheets were studied. Firstly, the plate was divided into three parts along the interfaces: CFRP layer, stiffener and rectangular plate. The stiffener and stiffened plate was, respectively, analysed by the Euler beam theory and the thin plate theory. The pretension CFRP sheet was analysed by the string theory. Then, the vibration frequency equation of the stiffened plate strengthened with pretension CFRP sheets was worked out, according to the interface stress equilibrium conditions and the displacement continuity conditions. The numerical results show an excellent convergence. The presented results are consistent with the results from the finite element software ANSYS. The analysis shows that along with the increase of the layer number and the prestress, the reinforcing effect of CFRP on the dynamic characteristics of the stiffened rectangular plate is more significant.

  • XIAO Han,DONG Xingjian,PENG Zhike,MENG Guang
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 130-134.
    Abstract ( 249 ) Download PDF ( 170 )   Knowledge map   Save
    The hydraulic antiresonant vibration isolator mounted in the helicopter isolation system can effectively attenuate the excitation force induced by the helicopter rotor. It possesses the advantages of easy installation, low damping over the levertype antiresonant vibration isolators which are facing the problems of high noise and serious wear. It is composed of two metal bellows and a supplementary spring and possesses an antiresonance frequency, at which the pressure vibration in the fluid induced by the inertial force is in opposite phase to the spring force of the isolator, specially suiting for the isolation of linespectrum vibrations. In the paper, two types of hydraulic antiresonant vibration isolator models were built and isolation bandwidths were developed which are related to the inertia mass and magnification ratio. Furthermore, a train of thought about a 2dof hydraulic antiresonant vibration isolator was put forward to obtain larger bandwidths.
  • WANG Weiji1,WU Wei2,ZHANG Jing3,ZHANG Yaqiong3,TA Na3,RAO Zhushi3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 135-141.
    Abstract ( 254 ) Download PDF ( 266 )   Knowledge map   Save
    To analyze the transient characteristics of the severe slugging in piping systems, an inclined pipelinevertical piping system was chosen as a modeling object, and a onedimensional numerical model was proposed to simulate the gasliquid twophase severe slugging. According to the stratified flow and the separated phase theories and based on this theoretical model, the four stagesof the severe slugging—slug formation, slug production, blowout and liquid fallback were modelled respectively. The relative error of the model between the calculated results and the experimental data in published papers is less than 10%, which validates the efficacy of the theoretical model. On this basis, the numerical simulation on the severe slugging phenomenon was conducted, and then the influence of the gasliquid inflow superficial velocities on the transient characteristics of the severe slugging was analyzed. The results show that the severe slugging phenomenon is obviously periodical in the inclined pipelinevertical piping system. With the increase of the gas superficial velocity, the period of the severe slugging decreases, while the pressure fluctuation at the bottom of the vertical pipe increases. The research results can be a reference for the system design and vibration prevention of piping systems.
  • WU Jiurong, Zhou Zeyu, LIANG Qiangwu, FU Jiyang
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 142-148.
    Abstract ( ) Download PDF ( 140 )   Knowledge map   Save
    By integrating the friction pendulum system (FPS) with the tuned mass damper (TMD) atop the highest floor of a highrise structure, the nonlinear dynamic equation for wind vibration control of the structure was proposed. The induced dynamic equation was solved by the Newmarkβ algorithm with internal iteration procedure. The new proposed FPSTMD system was then assumed to be installed atop the Guangzhou New TV Tower to investigate its wind vibration control efficiency. The effect of different structural parameters of the FPSTMD system on the windinduced displacement and acceleration response at the top of the Guangzhou New TV Tower were extensively investigated. These parameters mainly include the damping ratios of the main structure, the mass ratio of the secondary to primary structural systems, the friction coefficients and the radius of sliding chute. Comparing with the windinduced responses of the original noncontrolled structural system, the analyzed results show that more or the most efficiency for the windinduced vibration control could be obtained by selecting suitable design parameters of the FPSTMD system.
  • WANG Dehong1, JU Yanzhon,2, ZHENG Wenzhong1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 149-156.
    Abstract ( 239 ) Download PDF ( )   Knowledge map   Save
    To study the seismic behavior of frame joints made of reactive powder concrete with ultrahigh strength, toughness and durability, 4 reinforced reactive powder concrete beamcolumn joints were tested under cyclic loads simulated seismic load conditions. The failure patterns, seismic bearing capacity, hysteretic characteristics, ductility, energy dissipating, strength and rigidity degeneration of the reactive powder concrete frame joints were analyzed. The test results show that, the shearcracking strength of the reactive powder concrete specimens is higher, and the development of surface crack exhibits the characteristics of multiple fine cracking and a little concrete spalling, and the specimens remain as an integral whole as the loading ends.The strength and rigidity degeneration rates are small. The deformation capacity and energy dissipation are well. When the failure is occurring, the shear deformation is the double of that under the peak load, and the averaging equivalent viscous damping coefficient of specimens is 0.137, which is higher than the equivalent viscous damping coefficient of normal and highstrength concrete joints. The use of reactive powder concrete can improve the seismic performances of frame joints, including the shear ductility, energy dissipation capacity and so on, and reduce the stirrup ratio in joint core, which is conducive to the construction.
  • JIA Baohua1,LI Ge1,XU Zhenyang2,GUO Lianjun2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 157-161.
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    A finite element model of projectiles normally impacting aramid fiber laminates was established by using Abaqus/Explicit software, and the reliability of the model was verified by comparing the results with those in  existing literatures, then, the critical velocity of projectiles, the ballistic performance and the failure mechanism of the aramid fiber laminates were analyzed with three different shapes of projectiles normally impacting the aramid fiber laminates. The results show that the critical velocity of conical projectile is the smallest, the velocity of cylindrical projectile is the largest, and, the critical velocity of spherical projectile is something in between; with the same initial velocity, the conical projectile does the largest execution, the spherical projectile does the second, and the cylindrical projectile does the smallest; the failure mechanism of aramid fiber laminates is related to the shape and impact velocity of projectiles. The research results could provide references to the design and optimization of aramid fiber laminates and projectiles.
     
  • L Xiaohong1, 2, LUO Guanwei2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 162-167.
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    The mechanical model of a vibroimpact system with progressive motions was established. The probable motion states presented by the system between two consecutive impacts were analyzed, and their judgement conditions as well as motion equations were put forward. Numerical simulations were used to examine the bifurcation characteristics of the system with two types of periodic motions, including singleimpact periodic motions and p/1(p≥1) fundamental motions, and the periodic motion forms corresponding to the best progression. The results indicate that the best progression occurs in 1/1 motion, near the peak value of the impact velocity of the mass M1. Due to its own specific grazing singularity, the system presents two forms of nonsmooth bifurcations, namely, the realgrazing or baregrazing bifurcation and saddlenode bifurcation, in the process of transition from 1/n(n≥2) singleimpact subharmonic motion with progression to chaos, and in the process of mutual transition between adjacent p/1(p≥1) fundamental motions with progression.
     
  • ZHANG Chu1, ZHANGLiliang2, LIU Shi1, GAO Qing-Shui1, DENG Xiao-Wen1, YANG Yi1, YANG Jian-Gang2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 168-173.
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    The shaft torsional vibration model of an axial flow fan with variable frequency drive(VFD)was set up for the analysis of shaft break fault. The mechanical/electrical interaction effect of the fan with the vector convertor speed governing technique was considered. The variation of the driven shaft instant angular speed and torque during a run up process was simulated. The pulsation torque spectrum was given. The torsional vibration and the pulsation torque were measured in the field.It is shown that abundant harmonic components exist in the three phase signals output from the frequency converter. The harmonic components may coincide with the shaft torsional natural frequency in certain speed zone, which causes large torsional vibration and torque pulsation. In the high rotating speed zone, the selfexcited torsional vibration caused by the mechanical/electrical interaction effect may occur.The torsional amplitude of the shaft sections beside the both ends of the coupling is different due to the difference between the moments of inertia of the fan and motor. It causes high torque pulsation on the coupling and therefore the break of the shaft and coupling, which is of great influence on the safe and reliable operation of the fan. So, the torsional dynamics and shaft strength should be analyzed before the VFD modification.
  • TI Zilong,LI Yongle,XU Xinyu
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 174-181.
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    In longspan steel truss arch bridges, some of the slender local members are sensitive to wind forces. In order to investigate the onset wind speed of the vortexinduced vibration of local members in longspan steel truss arch bridges, a longspan steel truss bridge built in the coastal region was regarded as an engineering example. Based on the finite element method (FEM), a modelling approach called “zerodensity”, considering the stiffness of the entire bridge, the structural internal force and the length of gusset plates, was proposed to calculate the natural frequency of the local members. Based on the method of computational fluid dynamics (CFD), the aerodynamic characteristics of the sections of the local members were calculated and the lockin wind speed of vortexinduced vibration of the local members were analyzed and discussed. It is shown that using the “zerodensity” approach gives reasonable results of the dynamic characteristics of local members. The boundary conditions, structural internal force and length of gusset plates have notable influences on the natural frequency and lockin wind speed of the local members and using rigid boundary conditions in previous studies may overestimate the lockin wind speed, which may cause unsecurity.
  • SHEN Xianlong1,CHEN Yongqi2, LIU He2,ZHENG Jiujian1,ZHANG Haijiang1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 182-187.
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    Nonlinear static analyses (Pushover) are widely used in the seismic design and performance evaluation of building structures, nevertheless, it is still in the stage of exploration and method verification. Since the seismic responses of bridge structures may be significantly affected by highorder modes, three selected methods, the standard Pushover analysis (SPA), modal Pushover analysis (MPA) and upper boundary Pushover analysis (UBPA), were  applied to a bridge structure, namely the Jinghong bridge, with four different patterns of lateral forces, to evaluate its seismic demand. Based on the results from the nonlinear timehistory analysis (NLTHA), the efficiency and error range of the Pushover method in seismic demand estimation of the bridge were evaluated. The results show that when the merits of the MPA and UBPA methods are combined, the longitudinal seismic demand evaluation of ConcreteFilled Steel Tube (CFST) arch bridges are closer to the results from the NLTHA method. This combination can improve the accuracy of the evaluation. It is verified that the Pushover method is suitable for the seismic demand evaluation of CFST arch bridges, which can be used as an example for the seismic demand evaluation of practical engineering projects.
  • ZHU Yu1,2,YU Qiang1,XU Dengfeng2,GUAN Gaofeng1,MU Haihua2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 188-194.
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    The paper focuses on the stability problem that an inverted pendulum in an air spring vibration isolator connected in series with the inverted pendulum often moves to one side without going back to its initial equilibrium position or takes too long time to go back during use. The mechanical model for the stability of the inverted pendulum was established and the mathematical models of restoring force and restoring torque were deduced on the basis of an  indepth analysis on the influence of each structure parameter of the vibration isolator on the stability of the inverted pendulum. By simulating and analyzing the mathematical models in consideration of the actual case, the main structure parameters affecting the stability of the inverted pendulum were found. The results show that the oscillating rod length of the inverted pendulum and the radius of the upper piston mainly affect the stability of the inverted pendulum.
  • LI Nailu,XU Yan,XU Qing,GE Qiang
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 195-201.
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    The smart blade is the main direction of the intelligent control of wind turbine blades. The vibration of a blade can be significantly suppressed by the smart actuator installed on the trailing of the blade and furnished with a control algorithm. The key problem is the design of control rule based on the optimal identification to deal with the parameters’ change of the blade system in complicated operation conditions. Aiming at the control and suppression of blade vibration, the differential evolution (DE) algorithm was adopted to optimize the forgetting factor in the traditional recursive leastsquare identification and an optimal selftuning PID controller was developed based on the DE optimized identification. The proposed controller was implemented to control the system model, established in Matlab/Simulink. The simulation results show that the DE optimized selftuning PID controller performs well in suppressing the pitch angle and plunge displacement in the condition of parameter’s change. The overall vibration control effect might be further improved by the proposed controller in complicated operation conditions.
  • LIU Jijun1,GUO Jun1,LIU Xiaochuan1,ZHOU Junming2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 202-206.
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    The roller beam is one of the main loadbearing members of parachute locks. In the rocketsled tests of a parachute lock, the roller beam failure led to fail in opening the drag chute. According to the failure analysis, the mode of roller beam failure under impact is shear failure. In the paper, the roller beam impact shear failure mechanism was analyzed and it is shown that the parachute lock obtains an initial impact velocity under the action of the initial impulse of extraction parachute, and then collides with the roller beam, which causes the roller beam shear failure. The initial impact velocity and the equivalent mass of the motion mechanism were obtained by modelling the dynamics of the parachute lock, and the roller beam was modelled as a circular crosssection beam clamped at both ends under uniform impact load. The rigidplastic material model was used, and the thickness coefficient of the shear failure and the bendingshear interaction were taken into account. The threshold impact velocity of roller beam failure was derived based on the bendingshear theory. The effect of the mass ratio of the sleeve to the roller beam on the roller beam failure was discussed. Some improvements for structure design were proposed.
     
  • ZOU Mingsong1,2,3 LIU Shuxiao1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 207-211.
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    A fullscale numerical model was established to evaluate the acoustic radiation of a singleshell underwater ship, considering typical mechanical exciting loads on the ship. The sonoelastic method in Pekeris hydroacoustic waveguide was adopted to simulate the noisetesting state of a ship with forward speed in finite depth water. The radiated noise induced by inner excitation sources was measured at an observation point on one side of the ship. The effect of the sound pressure signal sampling duration on the assessment of the sound source level was investigated. On this basis, some suggestions on the selection of signal sampling duration were given to obtain the frequency spectral characteristics of the ship’s radiation more comprehensively and to make the observed results more stable.
  • ZHANG Yanlong1, WANG Li2, TANG Binbin1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 212-217.
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    Dynamical behaviors of a nonsmooth vibration system containing segmented damping, segmented spring and modified LuGre dynamic friction were investigated. The mechanical model and kinematic equation of the system were established. The movement transformation processes of the system were analyzed. The dynamical behaviors of the system, which converts among the modes of slipping, sticking, oscillation contact and chattering, were discussed by numerical simulations. The results show that the complex and diverse forms of the friction induced vibration like the friction induced stickingchattering vibration,the friction induced sticking vibration, etc.exist in the system with definite system parameters.

  • DONG Zhengfang1,2,ZHU Hongyun2, YAN Chao2, ZHENG Bin2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 218-224.
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    The fictionally truncated boundary must be treated properly in the seismic analysis of underground structures. In order to simplify the calculation, simplified lateral boundary, with vertical constraints and horizontal freedom, is a good choice. Based on the plane problem,a simplified lateral boundary was derived as if it was subjected to a far field shear stress state, and the rationality of the simplified lateral boundary was analyzed theoretically. Then the performance and width of the lateral boundary were evaluated through several selected benchmark numerical examples, namely the homogeneous soil layer, general thickness layered soil and thick layered soil. There are many factors influencing the width of the lateral boundary, such as the soil damping ratio, structure's scale, seismic characteristics and soil nonlinearity, whose influential degrees were studied through the dynamic time history method. It is shown that in general,the soil damping ratio and soil nonlinearity have similar effects on the width of the boundary, that is,the larger the damping ratio or the soil nonlinearity, the smaller the needed lateral boundary width,while the trend will be not too obvious when the large soil damping ratio and strong soil nonlinearity exceed a certain degree. It is also found that the structure's scale has some influence on the width of the boundary, that is ,larger size structure requires wider boundary width. The spectrum characteristics and the duration of seismic wave have great ereffect on the width of lateral boundary. 
  • ZHANG Jiangwei 1, LI Xiaojun 2, QI Jianfeng 1, WANG Yushi2, HE Qiumei2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 225-230.
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    There are vorious kinds of ground motion parameters influencing the stability of soil slopes under earthquake.The correlation of ground motion parameters with slope dynamic responses and the new methods for slope seismic stability evaluation have great theoretical and practical significance in the seismic design of slopes and the postdisaster emergency rescue. In the paper, based on the finite element numerical simulation and the mathematical method, 100 ground motion records with different parameters of peak ground acceleration (PGA), peak ground velocity (PGV), Arias intensity(AI), cumulative absolute velocity (CAV), duration and characteristic periods were selected. The dynamic responses of the slope under each ground motion were simulated, and the correlation between ground motion parameters and slope dynamic responses was discussed. The results reveal that the order of the influence weights of ground motion parameters on slope displacements from highest to lowest successively is PGV, PGA, Arias intensity, CAV, characteristic periods and duration, and that on slope output accelerations from highest to lowest successively is characteristic periods, duration, PGV, Arias intensity, CAV and PGA.
  • ZENG Liping1, CHEN Qiping1,SONG Liquan2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 231-237.
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    For a circumferential short spring dual mass flywheel (DMF) with singlestage stiffness, there is a certain empty angle between the primary flywheel and secondary flywheel for machining and assembly reasons. When the flywheel turns across the empty angle,the shock between the elastic element and flywheel may occur. By introducing a friction bearing block into the DMF located between the primary flywheel and secondary flywheel, and loading an axial pretightening force to produce friction torque, the shock between the spring seats and secondary flywheel caused by the empty angle can be released. Considering the friction torque and the piecewise stiffness owing to the clearance of the damping spring in the DMF, the torsional vibration model of the vehicle powertrain system equipped with the DMF and the corresponding nonlinear differential equations were established.The average method was applied in the derivation of the approximate solution of the system nonlinear frequency characteristics, and the influence of the input harmonic incentive amplitude and DMF parameters on the system nonlinear characteristics was analyzed. The study provides a theoretical basis for establishing the dynamic characteristics analysis model of the DMF which is fairly close to actual state and improving the vibration reduction performance of the DMF.
  • ZHOU Hechao1, XU Shizhou1, WANG Yajie2, ZHANG Jimin1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 238-243.
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    The finite element model of a ballasted track system was established in order to study the coupling effect between adjacent wheel sets. The research results indicate that due to the coupling effect between adjacent wheel sets the train loads should be treated as a series of loads from each bogie rather than from separated wheel sets. This coupling effect influences the stress of the ballasted track system seriously and when the coupling effect between adjacent wheel sets increases, the stresses of the ballasted track system rise obviously. Meanwhile, the stress distribution is also changed from “M” shape to inverse “U” shape gradually. Besides that,the simulation results point out the coupling degree becomes strong with the increased number of wheel sets and the decreased number of axle base. In terms of the common railway vehicles, due to the shorter axle base, the coupling degree between adjacent wheel sets is stronger for freight vehicles than for passenger vehicles. And in terms of the multiaxle bogie, the coupling degree increases not any more, when the number of wheel sets increases more than three.
  • QIN Xianrong,PAN Jie,XU Jian,ZHANG Qing,SUN Yuantao
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(6): 244-250.
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    In order to improve the efficiency of structural model updating of tower cranes, FEM updating method based on response surface was proposed. Based on the appropriate parameter selection and test design, an explicit function describing the relation between structural responses and the parameters to be updated was employed as a substitute of the traditional FE model. The FEM updating method has been conducted with different response surfaces on a cantilever beam and a tower crane. The effects and accuracy of the model updating method using different response surfaces were also compared. The results show that the FEM updating method based on response surface is better than the complicated FEM without model updating in the aspects of calculation efficiency and accuracy, and that the FEM updating method based on the quadratic polynomial response surface is better than that based on the radial basis response surface for tower crane structures. 