15 February 2018, Volume 37 Issue 5
    

  • Select all
    |
  • LI Xiaopeng, LIU Yang, WANG Xue, HU Dandan, MAO Xin, WANG Bingbing
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 1-6.
    Abstract ( 307 ) Download PDF ( 159 )   Knowledge map   Save
    On the basis of the traditional M-B contact model, adopting the 3-D fractal theory, the contact model of a 3-D fractal interface was derived and the 3-D fractal thermal contact conductance model was established. The effects of normal load, fractal dimension, fractal scale parameters, material characteristic parameters and couplings between any two of all these parameters on thermal contact conductance were revealed with simulation analyses. The results showed that the thermal contact conductance is positively correlated to normal load; when , There is a nonlinear relationship between them; when , they tend to have a linear relationship; when , thermal contact conductance increases with increase in fractal dimension; when , it decreases with increase in fractal dimension; thermal contact conductance is negatively correlated to fractal scale parameters, and it is positively correlated to material characteristic parameters; effects of couplings between any two of all these parameters on thermal contact conductance are also gained.


  • WANG Li CHEN Yong HUA Hongxing
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 7-12.
    Abstract ( 221 ) Download PDF ( 81 )   Knowledge map   Save
    The random vibration of a skewed propeller-shaft system induced by homogeneous turbulence was numerically investigated. Firstly, the unsteady pressure spectrum exerted on the propeller surface by homogeneous turbulence was computed with the correlation analysis method to obtain its spatial distribution. Secondly, taking the computed unsteady pressure spectrum as the input, the elastic vibration responses of the system were solved with the random vibration theory. The results were compared with those of the corresponding rigid propeller-shaft system. Finally, the effects of elasticity, damping, etc, on random vibration responses of the system were analyzed through varying the system’s             dynamic parameters. The results showed that the softer the shaft material and the harder the propeller blade material, the smaller the random vibration responses of the system induced by turbulence; increasing the system’s damping can obviously decrease vibration responses of the system near its natural frequencies. This study laid a foundation for further studying vibration and noise reduction of skewed propeller-shaft systems in submarines.

  • WANG Dayang, ZHANG Yongshan, TANG Chengzhi, HAN Qihao
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 13-19.
    Abstract ( 245 ) Download PDF ( )   Knowledge map   Save
    Dynamic models for RC frame structures with 4-floor, 8-floor, 12-floor and 16-floor covering common period ranges were established and verified to systematically investigate effects of hanging wall/footwall fault parameters on dynamic responses of RC frame structures. Three NGA ground motion attenuation relation models including ASK, CB and CY models were adopted to fit hanging wall/footwall earthquake records for purposes of comparison and optimization. The optimal fitting model was determined through comparison between fitted results and real 622 hanging wall/footwall ground motion records. Finally, 160 hanging wall/footwall earthquake samples with different fault parameters were fitted based on the optimal NGA model. The relations between hanging wall/footwall ground motion PGA and parameters, such as, earthquake magnitude, soil body shear wave velocity, fault dip angle and upper bound embedded depth were investigated. The effects of hanging wall/footwall fault parameters on dynamic responses of four RC frame structures were studied. The results showed that ASK model can simulate hanging wall/footwall earthquakes well and its simulated results agree best with real earthquake records; PGAs of hanging wall/footwall earthquakes increase with decrease in site distance and increase in earthquake magnitude; fault dip angle has a larger influence on PGAs within hanging wall site distance of 20 km; soil body shear wave velocity and upper bound embedded depth have little effects on PGAs; dynamic responses of four RC frame structures increase with decrease in site distance and soil body shear wave velocity, they increase with increase in earthquake magnitude and structure height; fault dip angle and upper bound embedded depth have almost no effect on structural dynamic responses under a certain footwall site distance; hanging wall earthquakes have a larger effect on dynamic responses of lower RC frame structures, while footwall earthquakes have a bigger effect on dynamic responses of higher ones.
  • WANG Dayang, ZHANG Yongshan, TANG Chengzhi, HAN Qihao
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 20-27.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Seismic isolation designs for four RC frame structures with different heights were conducted with Etabs platform to investigate effects of hanging wall/footwall fault parameters on dynamic responses of the isolated RC structures. The rationality of seismic isolation design models for the four buildings was verified from three aspects including wind resistance performance of isolation layer, eccentricity and compressive stress of isolation bearing. Based on the verified isolated structure models, effects of fault parameters, such as, earthquake magnitude, soil body shear wave velocity, fault dip angle and upper bound embedded depth on structural dynamic responses were investigated in detail under the action of 160 hanging wall/footwall earthquake samples. The results showed that the control effect of the isolated structures under hanging wall earthquakes is better than that under footwall earthquakes; the structural vibration reduction coefficient in horizontal direction and displacement of isolation layer are basically unchanged with variation of footwall site distance, while they have a concave shape changing tendency with variation of hanging wall site distance; the seismic isolation effect is the best within footwall site distance range of 20km~30km; the control effect of the isolated structures decreases with increase in earthquake magnitude and structural height and increases with increase in soil body shear wave velocity; the control effect keeps unchanged under footwall earthquakes and decreases under hanging wall earthquakes with increase in fault dip angle and upper bound embedded depth.

     
  • ZHANG Weifeng,ZHANG Zhitian,ZHANG Xianxiong,CHEN Zhengqing
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 28-35.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Besides identifying them directly from wind tunnel tests, aerodynamic admittance functions of bridge sections could be expressed using alternative methods. Through assuming Wanger function to be equivalent to Kussner function, Scanlan proposed using bridge flutter derivatives to express aerodynamic admittance functions. Hatanaka et al proposed using ‘equivalent’ Theodorsen functions to express aerodynamic admittances. Although both of them simplified identifying aerodynamic admittances, there were logical problems in the two methods. Here, flutter derivatives and aerodynamic admittance functions of a flat plate section and a rectangular section with a aspect ratio of 4 were identified with wind tunnel tests. Then, through comparing the measured aerodynamic admittances with those calculated using the above two methods, irrationality of the two methods was verified. The results indicated that with increase in the reduced frequency, the difference between the calculated aerodynamic admittances using the method of equivalent indicial functions and the measured ones gradually increases and tends to a limit value due to ignoring higher order motion modes, this method is applicable only when the wave length of fluctuating wind is much larger than the characteristic length of bridge sections; the aerodynamic admittances calculated using the equivalent Theodorsen functions are close to the measured ones within a lower frequency range, while they have a periodic fluctuating within a higher frequency range; for rectangular section of bluff bodies, this fluctuating becomes more significant; this fluctuation is due to adopting a certain ‘equivalent’ Theodorsen function to describe objects’ aerodynamic performance, once Theodorsen function changes, but its component functions remain unchanged to cause a logical mistake.
  • CAI Xiang, CAO Guo-hua,WEI Lei, WANG Lei, WANG Hai-xin
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 36-41.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to easily and quickly identify health operating state of hoisting wire rope of a vertical shaft with multi-rope friction, a method based on the line scanning image technique was proposed to detect transverse vibrations of hoisting wire rope at the boundary of the friction wheel and evaluate its load-bearing characteristics. Firstly, the line scanning image acquisition program was developed with VC++ to realize transverse vibration detection of hoisting wire rope and real-time recording. Secondly, the image edge extraction algorithm based on wavelet transformation was applied to recognize relative vibration deflections of hoisting wire rope. Finally, based on band pass filters and FFT transformation, transverse vibration natural frequencies of middle chord rope and load-bearing characteristics of hoisting wire rope were obtained in the process of the hoisting system running at a constant speed. Tests indicated that the proposed method can be used to overcome difficulties of recognizing the tension force of hoisting wire rope of a vertical shaft with multi-rope friction, it provides a guarantee for health running of vertical shaft hoisting systems with multi-rope friction.
  • CHU Ming1, 2 DONG Zhenghong3 REN Shanshan1, 2 JIA Qingxuan1, 2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 42-49.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Using a space-borne tandem arrest mechanism to do spacecraft docking is an important link of on-orbit operations. Impact force induced by docking is easy to cause disturbance and instability of the capture mechanism and the free-floating base. Aiming at the stabilization control problem of an unstable system after capturing, a generalized model for a series –wound flexible capturing mechanism with multi-stage controllable damping was proposed. Furthermore, integrated dynamic equations for the free-floating base-capturing mechanism coupled system were established using Kane approach. The global dispersive multi-stage damping forces were modeled as a particle swarm, and an objective fitness function was constructed. Based on the particle swarm optimization (PSO), a multi-stage damping optimal stabilization control for the unstable system was realized. The numerical simulation results of a certain type of space-borne 12-DOF flexible arrest mechanism showed that the proposed control method can significantly improve dynamic responses of the capturing mechanism and the free-floating base after docking to guarantee the system to be asymptotically stable. Finally, the capturing collision simulation test was conducted on the prototype of a two-joint four-stage damping flexible capturing mechanism. The effectiveness of the multi-stage damping stabilization control method was verified with the test results.

  • WU Hongyu1, WANG Chunjie1,2, DING Jianzhong1, WANG Jutao1, MAN Jianfeng3, LUO Min3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 50-55.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Single-leg dynamic simulation model of a novel lander was established, and the collision between lander and landing surface was simulated with a nonlinear spring-damper model. In order to improve the simulation accuracy of the model, its stiffness coefficient, damping coefficient and nonlinear exponent were taken as collision parameters and updated based on impact test results of the physical prototype of a lander with a single set of landing buffer. For improving the calculating efficiency, Kriging surrogate model was established to correctly describe the error between simulation results and test results. Then collision parameters were updated using the non-dominated sorting genetic algorithm II and taking minimizing the error calculated with Kriging model as an objective. The modified parameters were substituted into the simulation model to do a new simulation. Comparing calculation results of the simulation model before and after parametric updating, it was shown that compared with the impact test results, the lander’s main body falling distance error is reduced from 19.2% before parametric updating to 5.9% after that, the lander’s jury strut maximum buffering stroke error is reduced from 24.7% before parametric updating to 8.4% after that.
     
  • YAN Chang-feng KANG Jian-xiong YUAN Hao WU Li-xiao WEI Yao-bing
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 56-64.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The dynamic model of a rolling bearing can be used to analyze dynamic response characteristics of its local defect. During dynamic modeling of local defects in rolling bearing systems, bearing sliding, bearing elasto-hydrodynamic lubrication and bearing pedestal may not be considered. Here, a 2-DOF dynamic model for local defect displacement excitation in a rolling element bearing system was established under elasto-hydrodynamic lubrication and slip. Firstly, contact stiffness between rolling body and bearing race, lubricating oil film stiffness and damping, bearing pedestal stiffness and damping were calculated to obtain the total contact stiffness and damping. Then the actual running state of a rolling bearing was simulated considering rolling element slipping. According to Newton motion laws, dynamic equations of a bearing with local defect were built. The fourth-order Runge-Kutta method was used to solve these equations, dynamic responses of the bearing’s local defect were obtained. Comparing test results of a faulty bearing with the above simulated ones, the correctness of the established model was verified.
  • XIE Feng-yun JIANG Wei-wen CHEN Hong-nian XIE San-mao LI Xue-meng LIU Bo-wen
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 65-70.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Cutting chatter reduces quality and efficiency of machining, and it is an important study topic in cutting processing field. There are problems of measurement uncertainty and recognition model uncertainty in the traditional cutting chatter recognition method. Here, a generalized BP neural network cutting chatter recognition model based on the generalized interval theory was proposed. The quantities with measurement uncertainty were converted into generalized intervals with the generalized interval uncertainty analysis method, and a time-frequency feature extraction in generalized interval form was performed. Finally, the features in generalized interval form were substituted into the generalized BP neural network recognition model, the cutting states were indentified. The test results showed that the proposed generalized BP neural network recognition model has a higher recognition rate than the traditional BP neural network recognition model does.

  • PEI Hao, LONG Wei, YANG Shao-hua, GONG Ling
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 71-78.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to further improve working accuracy and stability of an air bearing, gas flow state and heat transfer characteristics of its inlet region were analyzed according to the impinging jet theory, the flow field of gas supply hole was divided into four parts including free jet zone, stagnation one, transition one and outlet wall jet one. Based on the two-dimensional planar flow function and the large eddy simulation method, it was determined that micro-vibration of gas film is caused due to three typical cyclonic forms in the inlet region including main cyclone near gas supply hole, sub-cyclone inside gas cavity and additional one at gas film inlet. The evolution mechanism, development law and varying trend of the three cyclones were clarified with the gas molecular motion theory combined with the surface-interface physical method. At the same time, relations among pressure change in gas film, 4 zones’ positions and ranges were studied, location and intensity of pressure fluctuation in gas film were analyzed. At last, vibration amplitude variation and frequency response function of gas film were measured on a test rig to verify the existence and distribution of the three cyclones, and the reasonableness of gas supply hole flow field partition. The influence factors and laws of gas film micro-vibration intensity were also given with the combination of numerical computation and test data.

  • SHI Zhi-biao1 CHEN Fei1 CAO Li-hua2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 79-84.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to improve the accuracy and efficiency of steam turbine rotor fault diagnosis,a fault diagnosis method for steam turbine rotor was proposed based on permutation entropy and relevance vector machine (RVM) optimized by improved fruit fly optimization algorithm (IFOA). The experimental data were decomposed with the complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN). The permutation entropy was calculated with IMF components being sensitive to fault features, it was used to construct the feature sample set. Then the "two fork tree" IFOA-RVM fault classifier was established to classify the feature set. IFOA was used to define two-stage fruit fly population search ranges to improve the search efficiency, meanwhile RVM kernel function was avoided to fall into local optimum. The fault data obtained on the ZT-3 steam turbine rotor analog test rig were studied. The results showed that compared with the fuzzy entropy, the clustering effect of the feature sample set obtained with permutation entropy is obvious; IFOA-RVM classifier is superior to FOA-RVM classifier in fault classification accuracy and efficiency; the validity and feasibility of the fault diagnosis method for steam turbine rotor based on permutation entropy and IFOA-RVM were verified.
  • CHEN Peng1, LI Wei2, ZHAI Min-gang3 WANG Dong-po4
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 85-91.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Excellent energy-absorption property of aluminum foam sandwich (AFS) structure is the crucial to ensure the safety and stability of bridge piers against rockfalls in mountainous areas. In order to analyze the effect of AF core thickness on energy-absorption performance of AFS panels, laboratory compression tests and dynamic finite element analysis were performed. The results showed that a double-layer AFS panel has a better energy absorption performance than a single-layer AFS one does under the same loading condition; for double-layer AFS panels, increasing the upper layer or/and the lower layer AF core thickness can effectively improve their energy absorption performance; the performance is no longer significant when core thickness increases to a certain threshold; an optimized proportion of AF core thickness is Tupper:Tlower = 3:2. The study results were applied to the demonstration project of YU Zixi bridge piers, the protection effect was remarkable.

  • FU Jiang-song 1 XU Jian 1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 92-97.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at no exact solution to transverse vibration of a rectangular plate with 4 free edges, an approximate solution to transverse vibration mode functions of this plate was proposed here. Following the fact that transverse vibration of a rectangular plate induces various standing waves, trying to combine them and approach the exact solution to mode functions of the rectangular plate, then an approximate solution to transverse vibration mode functions of this plate was formed. In order to verify the validity of the approximate solution, an experimental platform for the transverse vibration of a rectangular plate with 4 free edges was designed and made. The experimental results showed that a series of two-dimensional standing wave patterns (Chladni patterns) of the plate are obtained within the simple harmonic excitation frequency range of 0 to 2000Hz. Comparing the experiment results (Chladni patterns) to the standing wave patterns in the approximate solution, it was shown that they agree well each other qualitatively and quantitatively, so the correctness of the approximate solution is verified.
  • BA Zhenning1,2, CHEN Haowei1, LIANG Jianwen1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 98-107.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Wave scattering of arbitrary alluvial valleys in a layered half-space to incident plane SV waves was studied using the indirection boundary element method (IBEM). The model was divided into multiple independent closed regions and an open layered half-space region. Scattering wave fields of closed regions were simulated with fictitious distributed loads acting on closed boundaries, and scattering wave field of the open layered half-space region was simulated with fictitious distributed loads acting on open boundaries. Then, the densities of distributed loads were determined according to the continuity boundary conditions. The validity of the proposed method was verified by comparing the results using this method with those using the published method. Numerical analyses were performed for semi-cylindrical valleys with different separation distances and different numbers in an uniformly half-space. The numerical results showed that both surface displacement and amplification spectrum of the observed points are influenced by the above two factors, also frequency and angle of incident SV waves and observation points; the distance between valleys and the number of valleys have a larger influence on surface displacement amplitudes and peak values of amplification spectrum when SV waves propagate with oblique angle; with increase in frequency, the above two factors have a weaker influence on surface displacement amplitudes; displacement amplitudes are influenced severely with decrease in distance between valleys; due to the dynamic interaction among valleys, displacement amplitudes of multiple valleys are bigger than those of a single valley.
  • WANG Tao, XIAO Junjian,TAO Wei,TANG Jian
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 108-113.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at unideal heat transfer effect of traditional plain tubes under high Reynolds number,a method taking water with micro-Cu particles added as working medium to enhance heat transfer in plain tubes was proposed.The multiphase flow heat transfer model of Cu-water microfluid was established.The heat transfer Nu and friction factor f were computed by using Euler-Euler 2-fluid model based on the particle dynamics under different particle diameters of 10μm,50μm,100μm and 500μm,flow velocity of 1m/s,1.5m/s,2m/s and 2.5m/s,and particle volume fraction of 5%,10%,15% and 20%.The results indicated that Nusselt number (Nu) of Cu-water microfluid increases with increase in Reynolds number and particle volume fraction, and decreases with increase in particle diameter; the friction factor f increases with increase in particle volume fraction, and decreases with increase in Reynolds number; the heat transfer comprehensive performance evaluation factor η increases with increase in particle volume fraction, and decreases with increase in particle diameter; the heat transfer comprehensive performance of particles with diameter of 10μm is the best within the studied range of particle diameter, η reaches 1.1 to 2.3.
  • YANG Weibo, YUAN Shenfang, QIU Lei, CHEN Jian
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 114-119.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the lack of diversity in the particle filtering algorithm for fatigue crack life prediction, a method for prediction of fatigue crack propagation based on auxiliary particle filtering and structural health monitoring was proposed. Firstly, Paris rule of crack propagation was combined with the finite element method to build the state equation of crack propagation. Secondly, the active Lamb wave health monitoring technique was used to monitor the process of fatigue crack propagation. The time delay damage index was used to process Lamb wave signals, and then fit the function relation between crack length and damage index, the observation equation of crack propagation was established. The state space model for crack propagation was built through combining state equations and observation equations. Finally, the life prediction of hole-edge crack propagation was realized using the auxiliary particle filtering and the standard particle filtering, respectively. The comparison of the prediction results showed that the auxiliary particle filtering in fatigue crack propagation prediction of complex structures can effectively mitigate the lack of particle diversity combining the latest observation; its prediction results are more accurate; it is more applicable for realizing complex structures’ online fatigue life prediction.

     
  • ZANG Tingpeng1,WANG Fengren1, WEN Guangrui1,2, ZHANG Zhifen1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 120-125.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at deficiency in identifying modal parameters of a high speed rotor system using modeling approach, a new method for modal parameters recognition of a rotor system based on the empirical mode decomposition (EMD) and the stochastic subspace identification (SSI) was proposed here. Free damped response components of the rotor system’s various modes were obtained with the narrow band-pass filtering algorithm from the rotor system’s vibration responses under operation condition, and then EMD was used to decompose the processed signals and decrease the effects of mode mixing and other signal components. The random state model matrix of the rotor system was derived from a Hankel matrix constructed after using EMD with the singular value decomposition (SVD) and Kalman state filtering. The first and second order modal frequencies of the rotor system were identified with eigenvalue decomposition of the random state model matrix. The effectiveness of the proposed method was verified with simulation analysis and actual tests on a rotor system rig.



  • XIANG Ling,GAO Nan,TANG Liang,GUO Pengfei
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 126-132.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Studying dynamic features of wind turbine gear systems is of great significance to reduce faults of a system. For further investigating a wind turbine’s gear transmission system nonlinear dynamic characteristics, the lunped mass method was chosen, a torsional nonlinear dynamic model of the gear system was established considering nonlinear factors, such as, gear pairs’ time-varying mesh stiffness, gear mesh error and backlash and taking 1.5MW wind turbine rated power as the transmission power. The dynamic characteristics of the system were analyzed by using time history figures, FFT frequency spectrum diagrams, phase trajectories, Poincaré sections, bifurcation diagram and largest Lyapunov exponent diagram under variations of excitation frequency and gear mesh error. Results showed that with increase in excitation frequency, there are single periodic motion, quasi periodic one and chaos to appear in the system, the chaotic region also changes; with increase in mesh error, the motion of the system changes from quasi periodic one into chaotic one, and finally it becomes a quasi-single periodic motion; reducing mesh error weakens significantly the chaotic motion.

     
  • ZHANG Liangxiu1, WU Guangqiang1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 133-141.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to estimate the roll state of vehicles inexpensively and effectively, the method for roll state estimation and active roll control of vehicles considering road uneven disturbances was investigated. A 3-DOF vehicle lateral dynamic model was established, and Kalman filtering was applied to design a roll state estimation algorithm based on the vehicle lateral dynamics. To estimate the roll state induced by road uneven inputs, A 7-DOF vehicle vertical dynamic model was established and one roll state estimation algorithm was designed using the vehicle body vertical acceleration signals measured. On this basis, the expected vehicle additional anti-roll moment was determined with the sliding mode variable structure control method, and the vehicle active anti-roll control was realized by adjusting damping forces of four adjustable damping absorbers. Simulation results showed that the roll state estimation algorithm based on lateral dynamics can only estimate roll states induced by steer input, while that based on vertical dynamics can effectively estimate roll states induced by both steer input and road uneven input; adjustable damping absorbers can be used to effectively realize active control of vehicle roll states.
  • Zhao Lei, Guo Yu, Wu Xing
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 142-147.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Planet gear’s planetary motion causes time-varying vibration transmission path in a planetary gear box, its vibration responses are essentially different from those of conventional fixed-axis gearboxes, the traditional synchronous average method can’t be directly applied in a planetary gear-box. In order to solve this problem, the windowed synchronous averaging method developed abroad can effectively overcome the variable transmission path of planetary gear-box vibration. Here, the principle and realization for fault feature extraction of gear tooth crack of planetary gear-box were presented in detail based on constructing vibration separation signals and synchronous average. With this method, the characteristic of gear’s mesh tooth sequence was verified firstly. According to the characteristic of tooth sequence, the appropriate window function was selected to perform window interception of signals. Then the target gear’s vibration signals were constructed according to the rearranged gear tooth sequence and window intercepted signals. Finally, the synchronous average of vibration separation signals was done. The analysis for the actual measured signals of tooth root crack of a planetary gear-box showed that the presented method can be used to effectively extract fault features of a planetary gear-box.
  • ZHANG Ting1, TAN Zhixin1, ZHANG Heng1, FAN Chiaming2, YANG Zhiqiang1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 148-154.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To study axial coupled vibration response of a fluid-conveying pipeline excited by water hammer, the split-coefficient matrix finite difference method (SCM-FDM) combined with the implicit Euler method (IEM) was proposed to do numerical simulation for the pipeline 4-quation dynamic model with fluid-structure interaction. The proposed SCM-FDM was simple, easy and stable to implement since the appropriate difference formulas were selected according to the direction of wave propagation. Compared with the method of characteristics lines (MOCL), SCM-FDM avoids time-consuming calculations of spatial or temporal interpolations. To verify the applicability and accuracy of SCM-FDM, its computation results were compared with other authors’ numerical results and those of the water hammer theory, they agreed well each other. Furthermore, the effects of fluid velocity, fluid pressure, axial pipe vibration velocity and pipe-wall stress on the system’s vibration response features were analyzed in two cases including only considering Poisson coupling and considering both Poisson coupling and connection one. The results indicated that the effects of both two couplings on the axial vibration features of the fluid-conveying pipeline can’t be ignored; Poisson-coupling mainly affects amplitudes of vibration response, while the connection coupling affects both amplitude and frequency of vibration response.
  • CHEN Jian-en, SHI Yue-qi, LIU Jun, GE Wei-min, WANG Xiao-feng
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 155-162.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Vibrations of a pyramidal truss core sandwich beam with a skin breathing crack were investigated. Based on the zig-zag theory of sandwich structures, considering stiffness’s periodic variation due to breathing effect of crack, the system’s dynamic equations were derived. The effects of crack’s depth and location on the system’s natural frequencies were analyzed, and the influences of crack parameters on forced vibration responses of the sandwich beam were investigated with frequency response curves, waveforms and phase diagrams. The results indicated that super-harmonic responses of the sandwich beam are sensitive to crack parameters; geometric features of phase diagrams can be used to identify crack parameters.



  • LI Zhao-chun 1, ZHOU Bing-qian1, GU Quan1, WANG Jiong2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 163-168.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Response features of a magnetorheological (MR) damper as a shock isolation device with fast response requirement were modeled and tested. A theoretical model for response features of magnetic flux density was established according to the electromagnetic circuit of the MR damper’s coil. The response time constant of the model was determined with the frequency measurement method. Step responses of the magnetic flux density of the MR damper under different currents were tested. The results showed that currents with different amplitudes have no effect on response of magnetic flux density, the average response time constants are 4.9ms (rising step) and 2.8ms (drop step). Furthermore, a second order response model for shear yield stress was established. The step response of the shear yield stress of the MR damper under impact loading was measured utilizing an impact test rig. It was shown that the response time constant obtained with model fitting is 4.8ms; the proposed second order model for shear yield stress agrees well  with test data, so this model can effectively describe response features of the MR damper under impact loading.
  • LI Hui, SUN Wei, CHANG Yongle, LI Jian
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 169-174.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
     Based on Hilbert transformation technique, the time domain test method for nonlinear damping of a fiber-reinforced composite thin plate with amplitude dependence was studied. Firstly, by using Hilbert transformation technique, the expression for nonlinear damping of the composite structure system with amplitude dependence was derived, the theoretical principles of acquiring nonlinear damping parameters through time domain measurement were clarified. Then, the algorithm was written with MATLAB and numerical examples were used to prove the correctness of the algorithm. Finally, the reasonable and standard test procedures were summarized and applied in the real measurement of a TC500 carbon fiber/resin composite thin plate. It was shown that the proposed method can effectively acquire its damping parameters at different decay instants, so it can be used to quantitatively evaluate nonlinear damping characteristics of composite structures with amplitude dependence under different excitation amplitudes and frequencies.
  • YAN Shijun,PENG Jian, LIU Ze,LIU Yunsi
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 175-179.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Here, rigid-flexible coupled dynamic behaviors of a huge-type truck crane's boom system during its slewing hoisting were studied. A dynamic model for the system was built using Lagrange's equations and a hybrid frame reference to describe motions of the boom system and the lift load one. Using beam and rod elements to discrete the structure, a finite element analysis form for the model was constructed considering rigid-flexible coupled effects, inertial force effect and geometric non-linear ones of the system. A certain huge-type truck crane system was simulated with the proposed model, the results were compared with those of actual tests. It was shown that the proposed rigid-flexible coupled dynamic model has a better correctness.
     
     
     
  • LIU Xiao-feng 1 FENG Zhi-min 1 CHEN Yue-hua1 ZHANG Gang 1 LI Hong-wei2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 180-187.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to increase the signal to noise ratio (SNR) of piezoelectric signals in vehicle weigh-in-motion (WIM), it is necessary to determine reasonable embedding dimension and reconstruction order of the singular spectral analysis (SSA) de-noising algorithm. Here, a new stability method based on Cao algorithm was presented to determine embedding dimension, the variation value of cumulative energy contribution rate was used to determine reconstruction order. Gaussian white noise with different variances was added into Lorenz signal to do simulation, verify the feasibility and validity of SSA de-noising algorithm, and evaluate the effect of noise variance on the results. Five vehicles with different loads and at different speeds were used to perform the actual engineering tests. The results showed that when the vehicle speed is within the range of 10-50km/h, the average WIM error is controlled within the range of 2.72 to 4.72 %, so using SSA de-noising algorithm to process vehicle WIM piezoelectric signals can reach a better de-noising effect, the accuracy and stability of WIM can meet practical engineering requirements.
  • WANG Meng FENG Minhui TANG Enling HAN Yafei LIU Shuhua
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 188-193.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Morphology and distribution characteristics of ejecta cloud generated due to micrometeoroids or space debris impacting a spacecraft surface buffer structure were studied. A two-stage light gas gun was used to accelerate aluminum projectiles to perform hypervelocity impact tests. It was shown that aluminum projectiles’ impact an aluminum thin plate at hypervelocity to sputter high temperature particles or even tiny molten droplets, etc. flash heat sources, then ejecta cloud clusters composed of metal dust and micro-debris with low velocity; those ejecta cloud clusters produced by normal impact reveal a ring cone shape distribution, the higher the impact speed, the denser the distribution, within the impact speed range of 3-5km/s. Ultra-high speed camera HSFC-PRO was employed to capture the image evolution of ejecta cloud at different instants during initial impact stage. Ejecta cloud’s one dimensional expansion velocity was estimated through tracking front outlines of flash heat sources and ejecta cloud clusters. Attitude excursion of non-sphere projectiles during impacting might have more effects on distribution of ejecta cloud clusters.
  • LIN Xiu-fang 1,2 CHEN Shu-mei 2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 194-201.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Recently, MR damper has become an important smart semi-active control device. Firstly, to achieve its application in vibration control of a structural building, a new intelligent control strategy ICA-LQG combining the imperialist competitive algorithm (ICA) and the linear quadratic Gaussian (LQG) control approach was proposed to calculate ideal controlling forces. To overcome difficulties of determining weighted matrixes of LQG controller, ICA was adopted to optimize its parameters according to the constraint conditions for objectives to be optimized and damping force. Secondly, dynamic characteristics of MR damper based on Bouc-Wen model were obtained with tests. Finally, the clipped-optimal control (COC) was used to convert ideal controlling forces calculated with ICA-LQG into the control current of MR damper. To validate the effectiveness of the proposed semi-active control strategy ICA-LQG-COC integrating ICA-LQG and COC, a 3-story frame building was taken as an example, the aseismic results obtained with uncontrolled, two passive control, traditional LQG-COC and ICA-LQG-COC approaches, respectively were analyzed contrastively. The numerical results obtained under three seismic excitations demonstrated that in all control methods mentioned above, the proposed semi-active control strategy ICA-LQG-COC exhibits the most excellent comprehensive control performance and it can reduce the maximum displacement and acceleration responses of the structural building to the utmost extent.  
  • WANG Haimin, KONG Xiangshuai, LIU Huan
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 202-206.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Tri-eccentric butterfly valves are widely used in various industries, such as, water distribution, sewage, oil and gas plants. Butterfly disc and valve rod vibrations in tri-eccentric butterfly valveis play an important role in their structure design and application. Besides, there are few publications to study vibration characteristics of tri-eccentric butterfly disc and valve rod. If butterfly disc’s natural frequency is closed to Karman vortex’s shedding frequency, a resonance phenomenon occurs to destroy a tri-eccentric butterfly valve, and affect the whole machine’s normal operation. Here, to prevent a resonance phenomenon happening, a butterfly disc and a valve rod’s natural frequencies were calculated under high temperature and high pressure. For this purpose, the finite element software ANSYS and test verification were used. With an emprical formula, Karman vortex shedding frequency was calculated. The sufficient condition for no resonance was obtained. Moreover, the effects of butterfly disc and valve rod vibration on the tightness of a tri-eccentric butterfly valve were presented..
  • LI Chao1, CHEN Zhangwei1,HE Huinong2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 207-212.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A detecting system for performance of MR dampers was designed and developed. It could perform damping force-displacement tests and velocity feature tests of a MR damper under different excitations. Its electro-hydraulic position servo system was studied, a new real-time iteration control algorithm base on amplitude correction was proposed. Test results showed that this new control algorithm can effectively improve the amplitude-frequency characteristic dropping problem under higher frequency to reproduce sine displacement signals with higher accuracy and higher band width. Furthermore, a performance test for a LORD RD-8041-1 MR damper was conducted with this detecting system. Test results showed that this system can effectively detect the MR damper’s hysteretic characteristics curve to provide a premise for studying the dynamic model of the MR damper.


  • SU Qianqian 1,2 ZHAI Ximei 1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 213-220.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    According to Hamilton’s principle, a theoretical analysis model suitable for a simply supported beam and a K8 single-layer reticulated shell was proposed based on Lagrange’s equations. Firstly, the model was applied to calculate dynamic responses of a simply supported beam under tri-angular blast loads. Results showed that its vibration law, peak displacement, velocity, kinetic energy and internal energy are very close to those of FE analysis. Then, the theoretical analysis model was extended to calculate dynamic responses of K8 single-layer reticulated shell under triangular blast load. Influence laws of the number of generalized displacement parameters in deformation functions of the shell’s rods and peak load on response results were analyzed. Finally, based on analyzing the error between results of the theoretical analysis model and those of LS-DYNA FE analysis, the theoretical analysis model was improved. The applicability of this theoretical analysis model for calculating dynamic response of reticulated shells under blast load was proved.
  • SUN Xiaoyun1,WU Shixing1, HAN Guang1,TIAN Jun2,CHENG Qi1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 221-227.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Rock bolts are widely applied in bridges, tunnels, and buildings etc. In construction processes, due to influences of geological conditions, materials, architectures and other factors, there are many defects in anchoring systems. All these defects affect the life and safety of rock bolts, so it is very valuable to identify defects of anchor bolts. Artificial neural network can be used as an intelligent classifier to identify and classify defects of anchor bolts. Here, an adaptive threshold feed-forward neural network pruning algorithm was proposed, its essence was to judge the contribution value of hidden layer neurons in their learning processes to output, take the significant exponent as an index to delete redundant nodes of the network, and realize dynamic optimization and adjustment of the network structure. The simulation results showed that the proposed method can not only reduce the complexity of the network structure, but also improve classification and identification accuracies of anchor bolt defects.


  • MOU Xiao-long1, FENG Hui-hua1, ZUO Zheng-xing1, YANG Gui-Chun2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 228-233.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The perturbed force approach is a modal shape expansion method, it can also be derived from the perturbed eigenvalue equation. Here, the simplification of this method was discussed when tested eigenvalues were very much close to FE model eigenvalues to cause a singularity problem of eigen-matrix. Again using perturbation analysis, an arbitrary small shift was introduced to eliminate the matrix singularity and simplify the modal expansion matrix expressing. To avoid computation of a full matrix in actual application, the expansion of the generalized inverse of a matrix could be used to obtain a more efficient modal expansion scheme. Through implementing the generalized inverse expansion, the necessary conditions for the perturbed force approach being equivalent to SEREP method were gained. Finally, some criteria for FE modal base selection were proposed to choose lower order modal shapes and determine the number of modal expansion bases, a notched beam modal test demo was conducted to validate the discussion.

  • LIU Chang, WU Xin, LIU Tao, LIU Xiaoqin
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 234-239.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A new method based on near-isometric projection and support vector machine was proposed for fault diagnosis of rolling bearings. Firstly, Gaussian random projection matrix was utilized to do dimension reduction projection for the signal data to obtain the compressed data. According to the near-isometric projection property, the compressed data kept the structure of the original signals. Then the compressed domain features were extracted from the compressed data, they were taken as the input of a support vector machine to establish the fault diagnosis model of rolling bearings and realize fault diagnosis of rolling bearings. The actual measured data of rolling bearings in different faulty states were used to verify the new method. Results demonstrated the correctness and effectiveness of the proposed method.



  • Liang Dong1,2, Di Fangdian1, Chen Hongxia1, Duan Wenbo1, Li Zishuo1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 240-247.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Both results of study and engineering practice showed that the damping effect of a viscous damper is weakened when cable-girder coupled vibration happens. In order to ensure good vibration damping effect of a viscous damper under cable-girder coupled vibration, a cable’s compound vibration reduction method with a viscous damper and an added MTMD was proposed here. A simplified theoretical model with cable, viscous damper and MTMD was analyzed using the complex modal analysis method, and a test model of a cable-damper-MTMD system was designed. Both theoretical analysis and test results showed that the added MTMD designed according to the main contribution mode can assist the viscous damper to suppress the vibration of the main mode to utmost extent; the proposed method can effectively compensate the loss of damping effect of the viscous damper due to cable-girder coupled vibration.



  • HAO Chiyu1,2, FENG Guangbin2, YAN Pengcheng2, SUN Huagang2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 248-256.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to master the effects of broken tooth fault on dynamic characteristics of a conflux planetary gear in power shift steering transmission, a rigid-flexible coupled simulation model was established in RecurDyn environment based on MFBD (multi-flexible body dynamics). Through simulation, the dynamic stress distribution nephogram of the planetary gear system was obtained to determine dangerous points’ locations, the dynamic response characteristics of the conflux planetary gear system before and after considering flexible deformation were analyzed contrastively. Then the simulation model of broken tooth fault of the conflux planetary gear was built, fault feature extraction in time-frequency domain was performed using comparative analysis of its contact force and acceleration signals. The study results provided a basis for fault diagnosis and life prediction of conflux planetary gear systems.


  • DU Yong-feng1,2, DUAN Hao-cai2, XU Tian-ni2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 257-264.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The vertical progressive collapse mechanism of base-isolated structures and influences of structural parameters on the collapse mechanism were studied. Firstly, vertical pushdown tests of a single plane RC base-isolated frame were used to verify its simulation model built with the finite element software SeismoStruct. Then, SeismoStruct software and the nonlinear pushdown analysis method were adopted to analyze and compare multi-group FE structure models with different slab types, isolation bearings and aseismic designs. The results showed that slabs enhance the progressive collapse resistance capacity of base-isolated frames with beam action mechanism; the anti-progressive collapse capacity enhancement of frames with catenary action mechanism depends on the action width of slabs; With increase in fortification intensity, the anti-progressive collapse capacity of frames under both beam action mechanism and catenary one increases, but the capability increase in frames under beam action mechanism is more obvious; compared with non-base-isolated structures, the failure of base-isolated frames under beam action mechanism can be delayed in some cases due to constraints reduction of isolation layer; while the effects of increase in isolation layer horizontal stiffness on the vertical relative load-bearing capacity of base-isolated structures are small.