15 October 2018, Volume 37 Issue 21
    

  • Select all
    |
  • WANG Li,GUO Xiaonong,ZHU Shaojun, LUO Xiaoqun
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 1-7.
    Abstract ( 321 ) Download PDF ( 233 )   Knowledge map   Save
    In order to study free vibration characteristics of K6 and K8 aluminum alloy single-layer spherical latticed shells with gusset joints, large amounts of finite element (FE) analyses were performed using the software ANSYS considering effects of rise-span ratio, span, roof load, span-thickness ratio, grid density and constraint conditions, etc.parameters.Based on the FE simulation analysis results, the formula to estimate the fundamental natural frequency of single-layer spherical latticed shells not considering effects of joint stiffness was derived.Then, by introducing the amplification factor for the fundamental natural frequency, the formula to estimate the fundamental natural frequency of aluminum alloy shells considering effects of their gusset joints’ stiffness was proposed.Finally, the calculated value obtained with the proposed formula was compared with the measured fundamental natural frequency of a certain actual shell with gusset joints in tests.It was shown that both of them agree well each other, so the effectiveness of the proposed formula is verified.
     
  • WANG Piguang1,2,ZHAO Mi1,DU Xiuli1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 2-13.
    Abstract ( 254 ) Download PDF ( 195 )   Knowledge map   Save
    An analytical calculation formula was proposed to investigate earthquake induced hydrodynamic pressure on a uniform cylinder with arbitrary smooth cross-section.Based on the radiation wave theory, considering water compressibility, the exact calculation formula for hydrodynamic pressure on a uniform cylinder with arbitrary smooth cross-section was derived with the separating variables method, and its coefficients were determined utilizing the mode orthogonality of water and expanding a continuous smooth function into a Fourier series.The proposed formula was verified through calculating the earthquake induced hydrodynamic pressure on rigid uniform elliptical cylinders and round-ended ones.The results showed that the proposed calculation formula has a higher accuracy.
  • LI Jiasheng1,2, ZHANG Zhenguo1,2,HUA Hongxing1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 14-21.
    Abstract ( 287 ) Download PDF ( )   Knowledge map   Save
    A mechanical model was built for the double-direction fluid-structure interaction problems of marine propellers by the 3D frequency domain panel method combined with the finite element method.The added mass and damping matrices due to fluid-structure interaction were derived, and effects of propeller’s skew angle and incoming flow velocity on the two matrices were analyzed.The results showed that the incoming flow velocity significantly affects the added damping matrix, but it has little effect on the added mass matrix; when considering the effect of added mass, the larger the skew angle of propeller, the more the first order bending modal frequency of the propeller drops, while the opposite trend is observed for the first order torsional modal frequency of the propeller.The study methods and results provided a theoretical reference for design of low-noise propellers.
     
  • FANG Zhiwei1,2, HOU Hailiang1, LI Dian1, ZHU Xi1, HU Nianming1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 22-28.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    UHMWPE plate has excellent anti-penetration performance and usually needs to be cut into a certain size and then spliced and installed again in actual application.When high-speed fragments produced by implosion of semi-armor-piercing missiles penetrate UHMWPE plates in cabin of warship, their impact positions are random.Here, numerical simulation was used to study effects of fragment impact positions, fragment velocity and fragment length-diameter ratio on the anti-penetration performance of spliced UHMWPE plates.Result showed that when fragments start to impact a UHMWPE plate, fiber shear failure appears on the plate under combined action of bending moment and shear stress; when fragments continue to penetrate the plate, fiber tensile fracture failure occurs with a serious delamination phenomenon on the plate; when fragments penetrate two spliced plates with lower impact velocity (less than 1 000 m/s), the two spliced UHMWPE plates have an obvious anti-missile weak area, and the area is about three times of fragment radius; when fragments penetrate four spliced UHMWPE plates, the target plates can be divided into weak, sub-weak and normal areas; when UHMWPE plates are spliced and installed, considering sizes of fragments produced by implosion of semi-armor-piercing missiles and the convenience of installation processing, a 10 cm range on both sides of the splicing joint should be strengthened as an anti-missile weak area.
  • JIANG Haiming1, LI Jie1, WANG Mingyang1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 29-34.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Deep rock mass is a block-hierarchical structure, it plays an important role in rock nonlinear dynamic behaviors.Here, a test system was developed to investigate dynamic characteristics of deep rock mass.The test system mainly was composed of a loading device and a measurement system.Vibration exciters were taken as dynamic sources in the loading device to apply various forms of load dynamic and static combinations, such as, horizontal static load, horizontal impact and vertical impact to a structural system consisting of rock blocks.The measurement system consisted of acceleration sensor, charge amplifier, laser fiber displacement meter and dynamic signals measurement & analysis system.One-dimensional dynamic impact tests of a granite block model were performed to obtain the frequency spectrum and amplitude characteristics of elastic wave propagation.Test results showed that the test system's design is reasonable, it is easy to operate and has a high measurement accuracy; it can be used to study nonlinear rock mechanical phenomena of block rock mass.
  • XU Yazhou1, LOU Yanfang2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 35-40.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Here, random initial imperfection configuration of an oil storage tank was modeled with a linear combination of its buckling modes, and the imperfection amplitude was assumed to be a normal random distribution with mean of zero.Geometric initial imperfection samples were generated with Latin hypercube sampling method.Then, the incremental dynamic analysis method was employed to obtain the relation between the peak of acceleration and the maximum radial displacement of the tank wall, and according to Budiansky-Roth criterion, the critical buckling stress of the tank wall was determined under the action of earthquake.Furthermore, a user-defined subroutine based on ABAQUS was used to realize seismic response analysis of the imperfect oil storage tank with the added mass method.Finally, the reliabilities of the oil storage tank considering geometric initial imperfections and not considering them under the action of random earthquake were solved.The contrastive analysis showed that with increase in seismic action, the dispersion degree of the maximum compression stress of the tank wall increases; its probability distribution exhibits non-normal characteristics; the random geometric initial imperfections significantly reduce the aseismic reliability of oil storage tanks.
  • PENG Likun,QU Duo,XU Wenqi,CHEN Jia
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 41-45.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at problems of serious water hammers caused by closing ball valves in a ship trim balanced water transfer system, a test system including electro-hydraulic ball valve and digital stepping ball valve was built.Using the method of CFD valve-closing water hammer calculation combined with test study, influences of several valve-closing laws on system water hammer characteristics were analyzed.The results showed that compared with the single linear valve-closing law, the two-stage (first quick then slow) linear valve-closing law can effectively relieve pressure oscillation after fully closing valve; however, too large angle of quick valve-closing stage may cause water hammer pressure to rise, while smaller angle of quick valve-closing stage may cause the water hammer protection effect to be weak; here, the two-stage valve-closing law with quick-closing angle of 45% and the quick-slow speed ratio of 1.6 has a better water hammer protection effect.

  • CHEN Zhou1,2,YAN Quansheng3,DENG Deyuan4, CHEN Yuji1,JIA Buyu3,YU Xiaolin3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 46-51.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    With increase in span and structural flexibility of a footbridge, walking crowd may cause its large amplitude transverse vibration.Here, considering effects of geometric nonlinearity due to large displacements, aiming at a footbridge with lower fundamental natural frequency, its nonlinear transverse vibration model was built based on the relation between force and velocity.Millennium Bridge in London was taken as an example, and Galerkin method and the multi-scale method were used to do theoretical and numerical analysis for its large amplitude crowd-induced transverse parametric vibration.Comparing the results with the existing ones in literature, it was shown that the proposed method can be applied to predict the critical pedestrian number for different footbridges, and it is simple and convenient; the established model is reasonable and correct; the closer the walking frequency of pedestrians approaches two times of the footbridge’s fundamental natural frequency, the less the pedestrians are needed to cause the footbridge’s large amplitude vibration; at that time, pedestrians’ a slight stimulation can cause large vibration of the footbridge; when the number of pedestrians exceeds the critical pedestrian number, the bridge’s nonlinear vibration approaches a stable constant amplitude vibration; its linear vibration is a non-constant amplitude divergent one; pedestrian number per unit time, mass and damping per unit bridge length, and initial conditions have different level effects on the footbridge’s crowd-induced parametric vibration response amplitude.
  • ZUO Ye,SUN Guangjun, Wang Zhipeng, LI Hongjing
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 52-60.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Bridges’ seismic pounding leads to local damage of a structure, and even causes serious disarsters, such as, falling beam and collapsing.The irregularity of curved bridges makes their pounding effects be significantly different from those of straight beam bridges.A multi-scale finite element model of a typical 3-span curved bridge was established and poundings among its upper part’s main beams were simulated using the 3D contact-friction model combined with the explicit dynamic contact algorithm.The influences of pounding effects on the seismic response of the curved bridge under near-fault earthquake were analyzed.Meanwhile, a detailed parametric effect analysis was performed including ground motion parameters, pounding stiffness, expansion joint clearance and curvature radius, etc.parameters.The numerical results indicated that the seismic response of the curved bridge is significantly affected by inhomogeneous poundings and poundings restrict relative displacements of main beams; near-fault impulse earthquakes affects the pounding effect of the curved bridge more significantly than other two types earthquakes do; the maximum pounding force increases with increase in pounding stiffness and curvature radius, and decreases with increase in expansion joint clearance while main beams’ relative displacement response has the opposite changes; falling beam may occur at the curved beam outside due to excessive large outside tangential displacement.
  • LI Yijiang1, ZHANG Jinping1, LI Yungong2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 61-67.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on good performance of the variational mode decomposition (VMD) in signal processing and classification ability of the hidden Markov model (HMM) to time series, a rolling bearing wear state recognition method based on VMD-HMM was proposed.Firstly, VMD was used to decompose vibration signals of a bearing in its various wear durations, and the energy entropy of each IMF after VMD was calculated.Then, various IMFs’ energy entropies of bearing vibration signals in various wear durations were extracted to form eigenvector sequences.Finally, the randomly selected 20 groups in total 80 groups of eigenvector sequences for each wear state were input into HMM model to be trained, and the rest eigenvector sequences were tested.Through comparing logarithmic likelihood probability values, the bearing wear state was determined.The test results showed that the proposed method can be used to accurately distinguish the wear state of the bearing; compared with EMD-HMM and the harmonic wavelet sample entropy HMM model, it has higher recognition and accuracy.
  • DENG Bin 1,2,3 JIANG Changbo 1,2,3 LI Zhiwei 1,2,3 LIU Xiaojian 1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 68-77.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The characteristics of complex water flow in the swash zone are the key to the study of material transport in the nearshore zone, in which the diachronic variation of wave elements has complex nonlinear wave characteristics of non-stationarity, asymmetry and multi-scale variation, and so on.The action period and trend law of the wave element were analyzed, it is very important in order to understand the complex dynamic process of water and sediment in the swash zone.Based on the dam-break principle, a flume experiment was carried out to study the nonlinear wave characteristics of the scour current belt under the action of the surge wave with different slope.EEMD and HHT methods were used to analyze the experimental wave data, and the normalized wave energy spectrum, marginal energy spectrum and marginal energy spectrum were obtained, and the influence of water fluctuation on shoreline was analyzed with power spectral density.The results show that the wave energy of the current zone is mainly concentrated at the low frequency, which is lower than 1 Hz.Under the three experimental conditions, the maximum instantaneous energy gradually decrease along the shoreline direction.The maximum instantaneous energy appears and the currents have the strongest effects on shoreline, when the currents act on the shoreline for 2-3 s, 3-5 s and 3-6 s respectively.The steeper the slope of the beach is, the earlier the maximum instantaneous energy value appears, the greater the effect on the beach surface is.
  • YU Yuanlin1 2, YANG Yi1, LIU Fujun3, SHI Biqing1, XIE Zhuangning1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 78-86.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Here, 528 m high Nanning Wuxiang ASEAN Tower was taken as an engineering example, a new turbulent inflow generator named the narrowband synthetic random flow generator (NSRFG) was used to do the large eddy simulation (LES) for its wind-induced vibration response.Its base loads and displacement responses were calculated.The numerical wind tunnel’s simulation results were compared with those of the HFFB wind tunnel tests, and the effectiveness and correctness of NSRFG were verified.The results showed that the base bending moment power spectra simulation results in downwind and crosswind directions agree well with those of the wind tunnel tests, but the simulation results in torsional direction have a certain gap compared with the wind tunnel test ones; for the tower’s wind-induced vibration responses, the numerical simulation results in downwind direction agree well with the wind tunnel test ones, but the simulation results in crosswind and torsional directions are a little smaller; in across-wind direction, the predicted value for the vortex shedding frequency of the tower model with NSRFG was close to the wind tunnel test one.The study results provided a valuable reference for structural design.

  • ZHANG Chen, ZHAO Rongzhen, DENG Linfeng
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 87-91.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at problems of rolling bearings’ weak failures being difficult to identify, a rolling bearing weak fault identification method based on fusion of the variational mode decomposition (VMD) and the singular value entropy was proposed.Firstly, VMD was done for vibration signal of a rolling bearing to obtain 4 intrinsic mode functions (IMFs).According to a mean square deviation-Euclidean distance index, IMF components containing rich fault information were chosen to perform signal reconstruction.Then, the singular value decomposition (SVD) was done for the reconstructed signal to obtain the diagonal matrix of singular values, and the diagonal matrix’s singular value entropy was obtained using the information entropy theory.Finally, the singular value entropy was used to distinguish working state and fault type of the bearing.The new method was verified with rolling bearing vibration signals of American West Storage University.The results showed that compared with the traditional EMD singular value entropy fault diagnosis method, this method can more clearly delineate rolling bearing weak fault classes to correctly identify a bearing’s weak fault.This study provided a reliable basis for weak fault diagnosis of rolling bearings.
  • CONG Nan1,2,REN Yanxi1,CHEN Junda1,WANG Binxing1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 92-99.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    At present, non-stationary vibration simulation for vehicles only considers the non-stationarity of their vibration intensity.Due to effects of various factors in a ground-vehicle dynamic system, the actual vehicle vibration spectrum may also be non-stationary in frequency domain.Here, the wavelet packet decomposition was conducted for vehicle vibration signals, and the normalized column vectors of the wavelet packet coefficient matrix were clustered with the fuzzy C-mean clustering algorithm to realize automatic classification and statistics of vibration modes in vehicle vibration spectra.According to clustering results, a method that could produce a reconstructed vibration spectrum with frequency domain non-stationary characteristics similar to those of the original collected spectrum was proposed.This method was employed in reconstruction simulation for vehicle response spectrum on a block stone road of a certain test field.Compared with the original collected spectrum, the reconstructed spectrum has an ideal similarity in time domain, frequency one and amplitude probability density.The correctness and practicability of the proposed method was verified.The study results provided a method producing a reconstructed vibration spectrum with more realistic frequency domain non-stationary characteristics for vibration simulation tests of vehicles and other mechanical structures.
  • ZHANG Chuanxiong1,2,LI Zhengnong2,SHI Wenhai3,PAN Yueyue2,WANG Chequan2,WANG Yanru1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 100-107.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the actual measured data of a certain square high-rise building in Wenzhou, Zhejiang Province under different typhoons, multiple factors affecting the building’s aerodynamic damping ratio were comprehensively and contrastively analyzed using the SIMO ERA-NExT theoretical method.The results showed that with increase in the mean wind velocity, RMSs of the building’s vibration velocity and acceleration increase along a power function curve; within a small reduced wind speed range (<1.0), changes of the building’s aerodynamic damping ratio versus reduced wind velocity, and RMSs of structural vibration velocity and acceleration are not pure monotonous but piecewise; the change laws of the aerodynamic damping ratio under four typhoons are similar,the numerical value arrangement of their curves is related to the wind direction angle; the relation between the structural vibration acceleration power spectral amplitude and the aerodynamic damping ratio in X direction and that in Y direction have a similar law.

  • PENG Tao1, TIAN Zhongchu1, ZHANG Jianren1, ZHENG Wangan2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 108-116.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at finite element model updating for a long-span concrete cable-stayed bridge, a model updating method was proposed based on the multi-objective optimization to fully use the structure’s static and dynamic test data.The updating objective function was constructed using the structure’s static displacements and dynamic modal frequencies, etc.actual measured data, parameters to be updated were chosen based on the sensitivity analysis.The finite element model of a certain concrete cable-stayed bridge in China was updated with multi-objective optimization using the non-dominated sorting genetic algorithm-II (NSGA-II) to obtain Pareto optimal solution set to the problem of finite element model updating with multi objective optimization.The modified finite element model was verified with the measured static and dynamic data.The results showed that not only the updated model’s static displacements and dynamic calculation results involved in the optimization agree well with the measured values, but also the updated model’s static and dynamic calculation results not involved in the optimization are closer to the measured values; this static and dynamic finite element model updating method for the concrete cable-stayed bridge based on multi-objective optimization has a satisfactory effect, and the updated finite element model can accurately and fully simulate the actual structure.
  • LI Shichao,GAO Hongli, LIU Bokai, FU Guoqiang, LU Caijiang
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 117-125.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Studying force transmission characteristics of force-measuring system in impulse combustion wind tunnel can help to improve the accuracy of evaluating wind tunnel force measurement data.At present, this kind study is rare.A method for wind tunnel force-measuring system’s force transmission characteristics analysis based on the finite element simulation was proposed.Firstly, the dynamic model of the force-measuring system was established based on the parametric recognition method.The correctness of this built finite element model was verified using the system’s modal tests.Secondly, based on the theory of aircraft dynamics, force transmission characteristics between gravity center of an aircraft model and floating frame of a balance were selected to describe the force transmission characteristics of the force-measuring system.Then, a harmonic response analysis for the finite element model of the force-measuring system was performed to obtain force transmission characteristics between gravity center of an aircraft model and floating frame of a balance.Thirdly, the aerodynamic force acting on the aircraft model was equivalent to a concentrated force acting on the gravity center of the aircraft model, and the concentrated force was converted into a series of harmonic force components with Fourier transform.Based on the force transmission characteristics between the gravity center of the aircraft model and the floating frame of the balance, a series of harmonic force components were transferred from the gravity center of the aircraft model to the floating frame of the balance and then their new values were obtained.Finally, according to the balance test resolution, the harmonic force component unrecognized by the balance was screened.The ratio of this harmonic force component’s energy to the total signal energy was calculated to evaluate the force transmission characteristics of the force-measuring system.
  • CHEN Zhiyi1,2, TAN Zhong’ao2, LOU Menglin1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 126-133.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An underground structures’ simplified aseismic analysis method named the integral forced response dis-placement method was proposed to directly take soil deformation as equivalent earthquake loading.The fundamental idea and the specific implementation steps were introduced.Since the equivalent earthquake loading was obtained through free-field seismic response analysis, its accuracy was influenced by soil condition and the structure itself, so the accuracy of the integral forced response displacement method was also affected.The applicability of this method was analyzed through changing underground structure type, its burial depth and base soil stiffness.The results obtained with this method in vari-ous cases were compared with those using the dynamic time history analysis.It was shown that the integral forced response displacement method has a good applicability and a satisfactory accuracy in most cases, and the method is suitable for aseismic analysis and design of underground structures in soft soil.Considering the soil-structure relative stiffness in aseis-mic analysis of underground structures, the structure shear deformation correction coefficient R was proposed to modify this method.The checking calculations showed that the modified integral forced response displacement method has smaller er-rors and a wider applicability.

  • LIU Jun,2, HU min1, Chen Jianen1,2, Wang Xiaofeng1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 134-142.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at a cracked rotor’s nonlinear vibration problems, taking a Jeffcott cracked rotor with nonlinear restoring forces of bearing and electromagnetic actuator as a study object, its vibration response was analyzed through simulation and tests.An electromagnetic actuator with a neural network PID controller was adopted to realize the active control for nonlinear vibration of the cracked rotor.Through comparing the neural network PID control method and the traditional PID control one with simulations, it was shown that the neural network PID control method has better control performance and resisting disturbance ability for the nonlinear cracked rotor system.The opening-closing characteristics of a crack were analyzed based on the theory of rotor dynamics.The effects of different parameters on crack propagation were studied with the numerical method to propose the method for effectively delaying crack propagation.
  • WANG Jie1,ZHANG Jianzhuo1, AN Zhandong2, WANG Hui1,WANG Aiwen3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 143-149.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the problem of lack of test equipment for static-dynamic composite loading in studying the mine rock mechanics, and the load-bearing capacity of anti-scour support equipment and energy-absorbing structures, a kind of high-speed hydraulic impact test bench was proposed.It adopted a hydraulic loading form to do impact tensile and impact compression tests for specimens of different structures.Here, the structure and working principle of the test bench were analyzed.3 loading modes of the bench including static loading, impact dynamic one, and static-dynamic composite one were presented.The response characteristics of the bench were analyzed using the software AMEsim.The finite element dynamic analysis for the bench was also conducted with the software ABAQUS.After the prototype was made, anchor rods, etc.were tested.The results showed that the bench’s 3 loading modes are feasible, and the actual working conditions of specimens can be simulated by this loading test system.This bench provided a platform for studying dynamic characteristics of anti-scour support equipment and laid a foundation for further studying ultra-high energy level hydraulic impact test benchs.

  • ZHANG Shuai1,2,ZENG Ruili3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 150-157.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    As an important index of a diesel engine, its cylinder pressure directly reflects its combustion state.Due to complex operating conditions of the engine, it is in a non-stationary state under most conditions.How to improve the cylinder pressure’s recognition accuracy under multiple working conditions becomes the key of cylinder pressure recovery.Here, a new method for cylinder pressure recovery using vibration signals was proposed.Taking the maximum entropy spectral density of a vibration signal as its feature, Douglas-Puke algorithm was adopted to reduce the dimension number of input and output feature vectors.Finally, the BP neural network with multi-hidden layer optimized using the genetic algorithm was used to effectively restore the cylinder pressure curve of the engine under multiple operating conditions.The test results showed that after the average treatment, the maximum restoring error of the cylinder pressure curve’s peak values is 0.05 MPa and their maximum location error is 0.6  °CA to meet the accuracy requirement of cylinder pressure recovery.

  • CHEN Qiang1, 2, YANG Xuan2, 3, LI Yanbin2, 3, ZHANG Peng1, 2, WU Shaoqing1, 2, FEI Qingguo1, 2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 158-164.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the combination of the finite element method and the power injection method considering thermal effect, a simply-supported L-shaped folded plate was taken as a study object to investigate effects of nonuniform thermal load on statistical energy analysis’s parameters.Firstly, numerical analysis under the excitation of rain on a roof was conducted to verify the correctness of the acquisition method of statistical energy analysis’s parameters.Then the effects of temperature gradient and average temperature of nonuniform thermal load on structure’s modal density, internal loss factor and coupling loss factor were studied.The results showed that under the action of thermal load with different temperature gradients and the same average temperature, the L-shaped folded plate’s modal density drops and its internal loss factor and coupling loss factor simultaneously decrease with increase in temperature gradient; the effects of nonuniform distribution of thermal load on statistical energy analysis’s parameters of the L-shaped folded plate gradually increase with increase in the average temperature of thermal load.
  • LI Yongle1, WU Bing1,2, WANG Bin1, TANG Ping1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 165-170.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A great number of long-span truss bridges are built in mountainous areas nowadays.Their flutter performance is usually determined through their elastic sectional model wind tunnel tests.In tests, their main girder torsional centers are set at centroids of the models in general.However, influenced by several factors, the main girder torsional center of long-span cable bridges may offset from its centroids to result in the deviation between the wind tunnel test results and the actual situation.Here, the vertical offset of the torsional center of a truss bridge was simulated through its sectional model wind tunnel tests.Flutter critical wind velocities of a long-span cable-stayed bridge and a long-span suspension one with different torsional center offsets were measured.The effects of elastic rotating center formed due to torsional center offset, moment of inertia, and torsional frequency on these bridges’ flutter critical wind velocities were contrastively studied.The results showed that as a whole, the torsional center offset from centroid causes increase in a truss bridge’s flutter critical wind velocity.
  • ZHENG Hongbo1, QIN Hui1, HU Fang2, ZHANG Zhiyi1,3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 171-183.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The longitudinal stiffness of thrust bearings varies with shaft speed to lead to a propulsion shafting system has time-varying dynamic characteristics.Here, the dynamic interpolation adaptive method was proposed to control longitudinal vibrations of a time-varying shafting system.Firstly, a coupled vibration model for a propulsion shafting system was established, and frequency response functions of the control channel and the disturbance channel were obtained from frequency domain equations.Then, the dynamic interpolation adaptive method was used to dynamically fit the time-varying compensator model with interpolation algorithm and eliminate influences of time-varying characteristics on the stability of the vibration control algorithm.To verify the validity of this control method, numerical simulations were conducted for the adaptive control methods with and without dynamic interpolation, respectively.Simulation results showed that the dynamic interpolation adaptive method can effectively control longitudinal vibrations of thrust bearings to avoid divergence of the adaptive control system without interpolation; under the steady operation at different shaft speeds, the proposed control method can extremely suppress longitudinal vibration of thrust bearings, and the vibration acceleration amplitude after control is smaller than 1/20 of that with no control.
  • HUANG Jinghui1 LI Shouying1 LIU Min1 CHEN Zhengqing1 HUI Yi1 LI Hongxing2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 177-184.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Heat absorption tower of Noor III solar thermal power station in Morocco, Africa was taken as engineering background.The wind tunnel test results at University of Western Ontario in Canada showed that the tower displacement value under the designed wind velocity is 40% higher than the code value, but the structure’s vortex-induced vibration (VIV) critical wind speed is lower than the designed wind speed, and the response in crosswind direction within VIV area has a control action.Accordingly, an aero-elastic model for the tower was tested in wind tunnel.A 15 min-long acceleration time-history was collected at the top of the model under different structural damping ratios.Aerodynamic damping ratios were obtained using the random decrement technique and the extended Kalman filtering method, respectively.The results showed that aerodynamic damping ratios recognized with the two methods agree better each other; the total damping ratios recognized at different acceleration amplitudes firstly increase and then decrease with increase in acceleration amplitude; according to ASCE/SEI7-10, the identified aerodynamic damping ratio is negative and the minimum at wind speed of 6.5 m/s under the recurrence period of 50-year and C geomorphologic condition; these laws provide a reasonable explanation for the phenomenon of the response in crosswind direction within VIV area having a control action.

  • WANG Yong1, WANG Ruochen1, MENG Haodong2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 184-189.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Here, an inclined inerter-based vibration isolator with geometric nonlinearity was proposed.It was shown that the force of the inerter in moving direction of its bearing mass is nonlinear and the acceleration term in the system’s dynamic equation is also nonlinear.The system’s dynamic response was obtained using the harmonic balance method and then compared with the numerical solution.The vibration isolation performance of the inclined inerter-based vibration isolator was evaluated with peak dynamic displacement, peak transmissibility and vibration isolation frequency band.It was compared with the vibration isolation performance of an equivalent linear vibration isolator.The results showed that when the excitation force amplitude is smaller, compared with the linear vibration isolator, the inclined inerter-based vibration isolator has a smaller force peak transmissibility, a wider vibration isolation frequency band, and a larger  peak dynamic displacement.

  • GAO Nansha,HOU Hong
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 190-194.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Here, a new type oblique-section nested resonator was designed and its sound-absorbing characteristics were studied.Impedance tube test results showed that different combinations of single layer structures have a tunable low-frequency wide frequency-band sound-absorbing effect; the sound absorption mechanism is air frictions in micro-structure areas and structural resonances causing sound energy dissipated into heat energy.Acoustic-electric analogy model tests showed that sound absorption’s peak and bandwidth can be improved through changing resonator structures’ size and combinations; the proposed nested resonator is easy to fabricate, and has a guide action in low frequency sound absorption engineering.
  • LI Zengliang, DU Mingchao, DONG Xiangwei, FAN Chunyong, LIU Bin
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 195-203.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Studying impact process of a single angular particle is helpful to understand the material removal mechanism in erosion wear process.Here, a new type catapult for studying a single particle impact mechanism was designed, and this device could launch a single angular particle to hit a target material according to designed speed, angle and particle azimuth, and capture the dynamic process of particle impact using a high-speed camera.This device was used to conduct a test for a diamond-shaped hard angular particle hitting AA3003 aluminum alloy target material.The results showed that this device can be used to effectively study the influences of impact parameters including impact speed, impact angle, and particle azimuth on the impact behavior and material deformation mechanism, and realize studied variable controllability; the device is helpful to study the primary and secondary affecting factors in erosion wear process; impact angle and particle azimuth are key factors to determine the particle rotation direction, different rotating directions are corresponding to different material deformation mechanisms; the correlation between particle rotation and erosion mechanism is revealed by the particle motion trajectory image.The designed test device and method provided an effective means for studying meso-mechanical behavior of particle erosion.
  • JIAO Xiaolei1, ZHAO Yang1,MA Wenlai1,LI Siliang2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 204-212.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A three-parameter isolation system has better performances at resonance peak and within higher frequency band than the traditional 2-parameter one does.Here, a design method for normalized 3-parameter isolation systems was proposed.A 3-parameter isolation system’s time domain response analytical form was derived under sinusoidal and step excitations.For sinusoidal excitation, resonance peak and high frequency decay rate were taken as objective functions to perform the multi-objective optimization design.For unit step excitation, adjusting time and overshoot were taken as objective functions to do parametric design.Compared with the traditional design method, it was shown that the proposed design method can deduce solutions to simultaneously satisfy all objective functions; the feasibility of this method is verified with several simulation examples.
  • LIU Guang,LIU Jike,L Zhongrong
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 213-219.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The finite element model modification method based on time domain response sensitivity analysis is widely used in local damage and crack parametric recognitions of linear structural systems.Here, this method was extended in parametric recognition of a nonlinear system.Starting from the motion equation of this nonlinear system, its forced vibration response was obtained with the numerical integration method, and then the time domain response sensitivity with respect to each parameter was derived through differentiating the response with respect to each physical parameter to construct the corresponding response sensitivity matrix for parametric identification inverse problem.Parametric identifications for Holmes-Duffing nonlinear system and the dual-sine Gordon system widely used in physical engineering were taken as examples to illustrate the application process of the proposed method.The results showed that the response sensitivity analysis method can be used to accurately and quickly identify parameters of nonlinear systems, and it has the advantage of being insensitive to measurement noise.
  • WANG Haibo, HE Chongjian
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 220-226.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    For the state equation   used for nonlinear dynamics system, the generalized precise time step integration method for nonlinear dynamics system is proposed with the combination of the generalized precise time step integration method and predict-correct method. Firstly, in any time-subdomain, the vk is used to estimate the unknown vk+j/m(j=1,2,…m) in the process of computation. And then the discrete nonlinear terms are expanded by using Lagrange interpolation polynomial and treated as load. As a result ,the generalized precise time step integration method can be used to calculate dynamic response, which is an unified  computational and easy programming method. Compared with the four single-step methods, one predict-correct method or the predictor-corrector symplectic time-subdomain algorithm, the numerical results show that the proposed method is more highly accurate and stable, capable of keeping appropriate efficiency. The algorithm can be used to calculate the nonlinear dynamic responses of structural systems with multi-degrees of freedom.
  • GE Min1,GUO Han2,YU Haisheng1,WU Jiang3,GUO Huaiwei1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 227-232.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The compound planetary gear sets are widely used in full hybrid transmissions and taken as power-split devices to couple powers of motor and internal combustion engine.However, their complex structures have more gear meshing pairs and higher input rotating speed of motor, more complicated and serious gear whine problems come with them.Here, aiming at the gear whine noise problem of a certain full hybrid transmission, the excitation source making the maximum contribution to the gear whine noise was identified and the optimal noise target value was obtained through the whole vehicle’s measurement data analysis and subjective evaluation under the worst working condition.Then, the gear contact spot test verified the effectiveness of the simulation model.Finally, gears were micro-modified to optimize gear vibrations and gear whine noise quality, and make the gear whine pressure drop to the target value
  • DING Lei 1 ZENG Ruili 2 SHEN Hong 2 ZHAO Huimin2 ZENG Rong 1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 233-239.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Here, through analyzing operational trajectories of a piston pin under different fit clearances, aiming at the orderliness of cylinder cover vibration signals generated due to striking the piston pin and their difference in frequency components, considering the finiteness of test data, a method for choosing a wavelet packet’s sub-signals with Shannon entropy, extracting their features and then diagnosing faults with SVM was proposed.Firstly, a vibration signal of the piston pin was decomposed into several sub-signals with the wavelet packet transform and Shannon entropy of each sub-signal was calculated.According to Shannon entropy values, appropriate sub-signals were chosen and their energy was calculated and taken as their features.A support vector machine (SVM) was used to classify the piston pin’s different faults.The diagnosis test results showed that the proposed method can be used to identify and classify different faults of the piston pin.
  • LIU Fucai, LAN Hui,LIU Lin, ZHAO Xu
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 240-246.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to study motion characteristics of rotating hinges with clearance in motion process of a space mechanism under different gravity environments, the motion behavior of the mass center of a rotating hinge with clearance under different gravity environments was studied taking a crank-rocker mechanism with clearance as the studying object.Firstly, a continuous contact equivalent model was used to establish the model for the crank-rocker mechanism with clearance under the ground and space microgravity environments.Then, this model was re-built with the software of ADAMS, and simulation tests for the crank-rocker mechanism were performed, respectively with different clearances and crank rotating speeds under different gravity environments to complete the mass center’s motion characteristics analysis of a rotating hinge with clearance. The simulation results showed that the motion behavior of a rotating hinge with clearance’s mass center basically is not affected by crank rotating speed under the gravity of 0; the motion range of a rotating hinge with clearance’s mass center increases with increase in crank rotating speed under the gravity of 1g; the larger the clearance, the more easily the motion behavior of a rotating hinge with clearance’s mass center mutates.
  • XIN Yabing1,2, LIU Zhiwen1, SHAO Xudong1, LU Shandong2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 247-252.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to analyze non-stationary and non-Gaussian features of wind samples measured at mountain terrain bridge site, their non-stationarity was quantitatively detected firstly with the augment Dickey Fuller (ADF) method in statistics.Then, the time-varying mean speed of non-stationary wind was extracted with the wavelet transform method.Finally, Gaussian features of measured wind samples’ fluctuating wind speeds were contrastively analyzed with the stationary wind speed model and non-stationary one.The results showed that sudden wind samples may appear at mountainous terrain; for common non-stationary wind samples and sudden wind samples, their time varying mean speed maximum values calculated using the non-stationary wind speed model are greater than the 10min mean wind speed maximum ones calculated using the stationary wind speed model; fluctuating wind speeds of common non-stationary wind samples calculated using the stationary and non-stationary wind speed models, respectively are close to Gaussian distribution; fluctuating wind speeds of sudden wind samples calculated using the stationary and non-stationary wind speed models, respectively are non-Gaussian distribution.

  • CHEN Songlin, MA Wenran
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 253-259.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    D’Alembert method usually is applied in solving the initial problem of an infinite-long string free vibration.Based on the idea of this method, D’Alembert analytical solution to initial-boundary value problems of wave equation with Neumann boundary was studied.For initial-boundary value problems of wave equation within a finite long time interval, the method of variable separation was usually adopted to solve them.Two kinds of the continuation methods were used to solve these problems.One kind was that through successively extending time t, the time piecewise solution to an initial-boundary value problem of wave equation with Neumann boundary was derived within a finite long time interval.Another was that through extending definition fields of the initial displacement and initial velocity, D’Alembert type solution to an initial-boundary value problem of wave equation with Neumann boundary was derived within a finite long time interval.
  • MOU Jiegang1, LIU Tao1, GU Yunqing1,2, ZHENG Shuihua1, WU Denghao1,ZHOU Peijian1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 260-266.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to improve flow field fluctuation characteristics of a cycloid rotor pump, the pump model having a tongue oil groove structure with a capacity of increasing limit oil inlet and outlet areas was established.Using the numerical simulation method, the internal flow field in the pump model with tongue oil groove structure was calculated.The effects of tongue oil groove on pressure fluctuations at the rotor’s tooth top, tooth root and the maximum meshing volume were analyzed and the rotor’s axial pressure unevenness and axial flow field characteristics were studied.The results showed that the tongue oil groove structure can effectively improve the flow field’s pressure fluctuation of the cycloid rotor pump; the pressure fluctuation at the rotor tooth root drops by about 25%, the pressure fluctuation at the maximum meshing volume drops by about 54.2%; the structure has little effect on the pressure fluctuation at the rotor tooth top; the axial unevenness at the tooth root is about 3.5%, that at the tooth top is about 17.9%, that at the maximum meshing volume is about 3.1%; the smaller the volume between teeth, the larger the axial flow resistance to cause the deposition of high pressure fluid and axial unevenness.
  • LIU Xiaobo1,HAN Zidong1,SHAO Weiqin1, ZUO Hongyan 1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 267-272.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A double-grid correction wavelet clustering algorithm based on hash function was proposed to improve the efficiency of the double-grid correction wavelet clustering one.A hash table was used to eliminate empty cells in a quantized data space and reduce the complexity of the data space algorithm.Firstly, the eigen-space was quantized.Secondly, the hash function was constructed to form a hash table to store quantized eigenvalues in the hash table.Then, the wavelet transform was conducted for the original grid and the corrected one on the hash table simultaneously to find connected elements in different layers of the eigen-space.Finally, the clustering results generated by the corrected grid were used to correct those generated by the original one, and the final clustering results were obtained.This method was applied in rotor fault diagnosis of an aircraft engine.The test results showed that the proposed algorithm improves the rotor fault diagnosis’s efficiency based on ensuring its accuracy.
  • WU Wenpeng1,2,3, LI Lifeng2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(21): 273-280.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A bridge is a structural system consisting of various interrelated and interacting components, and any component’s damage under earthquake affects the bridge’s functional integrity.Adopting a single component fragility to express the bridge’s system fragility may over-estimate the bridge’s aseismic capacity.A multi-span RC continuous girder bridge was taken as an example, and its finite element model was constructed with the software OpenSEES to conduct a great number of nonlinear time-history analyses.Simultaneously considering seismic damages of bridge pier, lead core rubber bearing, plate-type rubber bearing and bridge abutment, the bound estimation method, Monte-Carlo simulation one and the product of conditional marginal (PCM) one were applied to establish the bridge’s system seismic fragility curves.These fragility curves were contrastively analyzed to judge the applicability and reasonability of the three methods.The results showed that the traditional bound estimation method and the PCM one depend on component fragility analysis results, while Monte-Carlo simulation method is able to directly construct the bridge’s system fragility curve and to independently consider effects of various uncertainties; the PCM method can be used to quickly construct the bridge’s accurate system fragility curve, and it is more applicable for the bridge system fragility analysis considering multiple failure modes.