15 March 2018, Volume 37 Issue 7
    

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  • SUN Rui1 LI Xiaofei2 CHEN Longwei1 YUAN Xiaoming1 LI Bo2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 1-7.
    Abstract ( 285 ) Download PDF ( 288 )   Knowledge map   Save
    The key for using a hyperbolic model to describe stress-strain relationship of liquefiable soil is to determine its cyclic maximum shear modulus and its cyclic ultimate shear stress under cyclic loading. Aiming at several kinds of sand soil with different relative densities, liquefaction tests under the action of cyclic stresses of different equal-amplitudes were uniformly consolidated using a new high-precision dynamic tri-axial apparatus to study effects’ mode and law of pore-water pressure on maximum shear modulus and ultimate shear stress of saturated sand soil. Formulas to calculate cyclic maximum shear modulus and ultimate shear stress of sand soil with different precisions were proposed considering increase in pore-water pressure. The results showed that effects of increase in pore-water pressure on cyclic maximum shear modulus and ultimate shear stress of sand soil are obvious, sand soil’s cyclic maximum shear modulus and ultimate shear stress decrease with increase in pore-water pressure; the relation between saturated sans soil’s maximum shear modulus and pore water pressure ratio can be expressed as a unified linear relation expression to be independent upon sand soil types and their relative densities, pore water pressure ratio is equal to the relative reduction of cyclic maximum shear modulus; the relation between cyclic ultimate shear stress of saturated sand soil and pore water pressure ratio can accurately be expressed as a quadratic curve relation to be dependent on sand soil types and their relative densities, it also can be expressed as a unified linear relation expression to be independent upon sand soil types and their relative densities considering simplification, pore water pressure ratio is equal to the relative reduction of cyclic ultimate shear stress; Hardin initial maximum shear modulus calculation formula is not suitable for calculation of cyclic maximum shear modulus considering increase in pore water pressure, Hardin formula generally overestimates sand soil’s cyclic maximum shear modulus in liquefaction process; especially, the cyclic maximum shear modulus can be overestimated almost 80%-140% within the sensitive interval of pore water pressure ratio of 0.6 ~0.8.
  • WANG Shiyu1,2, XIA Ying1, SUN Wenjia1, WANG Yaoyao3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 8-12.
    Abstract ( 252 ) Download PDF ( 54 )   Knowledge map   Save
    Aiming at elastic vibration problems of external rotor in an asynchronous induction motor due to rotating magnetic load, a synchronous coordinate system rotating at the same speed as that of the magnetic load was employed to remove influences of time-variant parameters. A time-invariant transverse vibration model of the external rotor was established with Hamilton principle. It was solved by using the classical vibration theory. Effects of the motor’s basic mechanical-electrical parameters on the system’s vibration stability were analyzed and the unstable boundary with a closed-form was also derived. A coordinate conversion was used to build the external rotor’s parametrically-excited dynamic model under a conventional inertial coordinate system. The system’s divergence and flutter unstable regions were calculated with Floquet theory. The system’s responses were solved using Runge-Kutta method. It was shown that the results obtained with the two dynamic models agree well, the correctness of the modeling method with a synchronous coordinate system and the dynamic stability calculation results is verified.


  • HAN Tao LIU Wei ZHANG Zijun ZHAO Tonglai LIU Yongshou
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 13-22.
    Abstract ( 197 ) Download PDF ( 64 )   Knowledge map   Save
    The geometry of air pipeline system is generally complicated, such as, L-shaped, U-shaped, Z-shaped configurations and so on, but they contain a typical pipeline basic element of “straight pipe-curved pipe”. Here, an algorithm based on straight-curved assembly pipeline was proposed to realize more efficient modeling and modal analysis of complex pipeline systems. Starting from 3-D vibration governing equations of a straight pipe element and a curved one, respectively, discrete modes and dynamic stiffness matrices of pipe elements were derived based on frequency dispersion relation. Then all straight pipe elements and curved ones were assembled under a global coordinate system, the whole pipeline system’s dynamic stiffness matrix and characteristic equation were established. Finally, the proposed algorithm was validated. This method was used to analyze the influence law of piping layout on natural frequencies of Z-shaped pipes and deduce   the empirical formula. Tests showed that the results of the empirical formula agree well with those of tests, their error is less than 5%,, so the empirical formula can be used to design Z-shaped pipes within an allowable error range.

  • HE Hao-xiang1,2, ZHANG Xiao-fu1, WANG Xiao-bing1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 23-31.
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    Although there are many literatures about effects of temperature on bridge structures’ frequencies and related statistical methods, few studies reflect dynamic performance and time-varying frequency characteristics of bridge structures under the combined action of multi-environmental factors. Adopting the co-integration theory with the ability to quantify the long term balance relationship among multiple non-stationary sequences, a 3-span RC bridge model under natural environment were monitored and analyzed continuously, a model for long-term balance of temperature-humidity-frequency based on the co-integration theory was established to study the comprehensive effects of temperature and humidity on the bridge’s frequencies. The results demonstrated that the established model has a better fitting precision and a predictive ability, it can fully reflect essential characteristics of influences of temperature and humidity on bridge frequencies; based on this co-integration model, the bridge frequency modification model considering effects of multi-environmental factors is proposed to effectively eliminate effects of temperature and humidity on bridge frequencies, and accurately reveal bridge’s dynamic feature variation due to structures’ internal causes, it can provide effective information for bridge damage diagnosis and safety assessment.
  • LIU Zhangjun1,2, LIU Zenghui1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 32-37.
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    Based on a continuous proper orthogonal decomposition (POD) of time-spatial stochastic fields, a hybrid continuous POD-random function approach for simulation of time-space stochastic fields was proposed by introducing random function expression forms of orthogonal random variable sets. Utilizing the continuous POD technique based on the cross power spectral density function (CPSDF), a stochastic field was expressed as a superposition of finite lower order proper modes to realize the order reduction treatment of the original stochastic field. With the random function expression for orthogonal random variable sets, an original stochastic field was accurately described in the second order statistical meaning using only two basic random variables. It was shown that the number of basic random variables in the proposed approach is the minimum compared with that in the classical POD approach; all representative time histories of fluctuating wind velocity obtained construct a complete probability set. Lastly, taking Kaimal fluctuating wind velocity spectrum as an example, a stochastic wind field in horizontal direction was simulated and analyzed to verify the higher accuracy of the proposed approach.
  • XU Jiajia, LIU Hao
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 38-42.
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    Part of pole points allocation problem of a single-input vibration control system with time-delay was studied. A multi-step method for solving the similar problem of a multi-input vibration control system was proposed, the unwanted eigenvalues were changed into the given ones and all other eigen-pairs kept unchanged. This method was easy to be programmed and implemented, it didn’t need to use a dynamic flexibility matrix or solve Sylvester equation. Numerical examples showed that the multi-step method is effective.

  • HUANG Ya-ming1,2 CAO Shu-qian 1,2,3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 43-51.
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    For a dual-disc rotor system supported with rolling bearings, its dynamic model fully considering VC (varying compliance) vibration arising due to periodic change of rolling bearings’ stiffness was established by using Lagrange equation. Forces exerted on the rotor system due to bearings having local damage on outer and inner rings were analyzed. With the method of numerical integration, the system responses were obtained. The effects of bearings’ outer and inner rings damage on dynamic characteristics of the rotor system were studied. It was shown that damages of bearings’ outer and inner rings have larger effects on dynamic characteristics of the rotor-bearing system, these damages can enlarge the system’s vibration, especially, within a lower rotating speed range, the system’s vibration amplitude increases with increase in damage width; damage on outer ring interferes nonlinear factors of bearing clearance, while damage on inner ring enhances the action of these factors.

  • LI Shuaijun1, LI Huafeng1, WANG Xiaofeng1, LIU Gongmin2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 52-55.
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    Based on moment and force equilibriums and fluid continuity conditions at a pipe branches’ junction, the general formula for dynamic transfer matrix of branched pipes was established. The transfer matrix method in frequency domain for calculating dynamic responses of fluid-filled multi-branched pipes was proposed. The correctness of the proposed model and algorithm was validated using test data of cross-shaped pipes with various boundary conditions. Then, forced vibrations of branched pipes were analyzed considering effects of different branch angles and positions. The results showed that compared with pipeline structural vibration, fluid pressure fluctuation is more easily influenced by variation of branch angles and positions; the effects of branch angle changes on pipeline structural vibration and fluid pressure fluctuation have a certain selectivity, while the effects of branch position changes on pipeline structural vibration are more complex.


  • LU Shanbing 1, JIANG Weibo2, ZUO Wenjie1,3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 56-61.
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    Equivalent static loads method (ESLM) was introduced to study size and morphology crashworthiness optimization for automobile frontal structures to reduce maintenance cost and realize lightweight design of automotive frontal structures under lower speed frontal impacts. Taking minimizing the mass of automotive frontal structures as an objective function,   thickness sizes of automotive frontal structures and morphology node coordinates as design variables, and invading quantity and process requirements of stiffeners as constrains, the crashworthiness optimization design was conducted. ESLM was used to convert this nonlinear and transient crashworthiness optimization problem into a multi-mode linear static optimization one. Numerical examples showed that ESLM can effectively be used to solve crashworthiness optimization problems and obtain their optimal solutions with a higher accuracy.

  • LI Huan1,2,HE Xu-hui1,2,WANG Han-feng1,2,LIU Meng-ting1,PENG Si1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 62-68.
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    π type cross-section of main beam vortex-induced vibration(VIV) is one of important factors influencing its wide-spread usage in long-span bridges. Taking a super high cable-stayed bridge with three towers as a certain engineering background, its VIV performances in a construction state were investigated with a sectional model in wind tunnel. Test results showed that the bridge suffers remarkable VIV within the designed wind velocity range; within the specified range of damping ratio in the code, amplitudes of the bridge’s VIV are larger than the specified value in the code; in order to suppress VIV of the main beam, flow-isolating plates and lower stabilizers are designed as aerodynamic vibration-reduction measures; the vibration-mitigation effect of flow-isolating plates seems to be limited, however, lower stabilizers have a better VIV-suppressing effect, they also satisfy the requirements of flutter stability. Finally, the mechanism for VIV-generating and suppressing was preliminarily discussed with CFD numerical simulation method.


  • WANG Hao KE Shitang
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 69-76.
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    Taking a domestic super large steel cylindrical-cone cooling tower (189m) to be constructed as an example, numerical wind tunnel tests were conducted based on large eddy simulation (LES) to get 3-D aerodynamic force histories on its surface and flow-field distribution state around it. Comparing the numerical simulation results with those of field measurements home and abroad and actual wind tunnel tests, their correctness and effectiveness were verified. Furthermore, the traditional peak factor method, the improved peak factor one and Sadek-Simiu one were employed to analyze the peak factor and the extreme wind pressure of this cool tower contrastively. The 1-D and 2-D fitting formulas for the extreme wind pressures of cylinder and cone parts of the tower and suggestions of value-selecting were deduced based on the non-linear least square method. The study showed that the wind loads on the cool tower’s surface negative pressure extremum zone and near the separation zone reveal obvious non-Gaussian features; the extreme wind pressure values calculated with the peak factor method based on Gaussian distribution are smaller than the specified value in the code; the extreme wind pressures at leeward side of cylinder part and cone part are greater than the specified value in the code; the extreme wind pressures at windward side and lateral wind side of cone part are close to the specified value in the code GB/T 50102-2014, while the extreme wind pressures at windward side and lateral side of cylinder part are close to the specified value in the code GB50009-2012; the calculated results with fitting formulas for extremum wind pressure proposed here agree well with those actually measured on the tower; the main conclusions obtained here provide a reference for wind loads design of this type cool tower.
  • SHI Qing-xuan, WANG Feng, SANG Dan, WU Chao-feng, WANG Peng
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 77-84.
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    The models of concrete-filled steel tubular (CFST) diagrid tube structures were analyzed with the nonlinear static elastic-plastic time-history analysis method, the nonlinear dynamic elastic-plastic time-history analysis one and the software PERFORM-3D. The structural yield path, lateral displacement, floor drifts, shear hysteretic effect, oblique column damages and their distribution mode were studied. The results showed that CFST diagrid tube structures have a clear force transmission path, a larger lateral stiffness and better spatial working performances; the main and secondary nodes can effectively balance internal force differences of oblique columns, so deformations of node layers are smaller than those of non-node layers; shear hysteretic ratio of diagrid tube structures changes from positive values to negative ones along the floor’s height, the position of negative shear hysteretic ratio occurring for the first time drops with the development of structure’s plasticity; different earthquake waves and different acceleration response amplitudes have a larger influence on damage of oblique column layers, while they have a smaller effect on damage distribution mode of oblique column layers.
  • SHEN Guo-hui1, ZHANG Yang1, YU Shi-ce1, ZHU Min-jie2, ZHENG Zhao-yang2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 85-90.
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    In order to study aeolian noise generated by a smooth circular cylinder under different wind speed conditions, an acoustic wind tunnel was built to conduct aeolian noise tests of rod system type structures. The wind tunnel tests for circular cylinders of 11 diameters were conducted under 4 wind speeds. The frequency spectra’s characteristics and dominant frequencies of aeolian noises generated by circular cylinders were analyzed. Finally, the variation laws of accumulative dominant sound pressure levels and dominant frequency band widths with varying wind velocity and Reynolds number were investigated. Results showed that dominant frequencies of wind noises generated by circular cylinders are proportional to wind speed and inverse proportional to diameter of circular cylinder; Strouhal number calculated from dominant frequencies within Reynolds number range of 3e3-1e5 is about 0.20, it has a gradually decreasing trend with increase in Reynolds number; the accumulative dominant sound pressure levels increase with increase in Reynolds number, they disperse more within a lower Reynolds number range of less than 3e4, and less within a higher Reynolds number range.


  • JING Li 1,2 YANG Zhichun1 ZHANG Jiaqi 2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 91-95.
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    In the field of structural damage detection, different damage detection methods have different sensitive level to structural damage. In order to improve the accuracy of structural damage detection, information fusion technology was used in structural damage detection here. Using the weighted average method, the simply voting method and the D-S evidence theory, information was fused at different levels, structural damage state was obtained. The feasibility and effectiveness of the proposed method were verified using honeycomb sandwich composite beams damage detection tests. The results showed that the proposed method can accurately figure out if structural damage happens and structural damage’s position.


  • HAO Wenqian, XIE Jiamiao, ZHAO Xiang, WANG Fenghui
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 96-101.
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    The mechanical behaviors of a thin-walled sinusoid corrugated tube under axial loading were investigated. Introducing eccentricity factor, amplitude factor and considering strain- enhancing effect of material, the theoretical model for plastic buckling of a sinusoid corrugated tube was proposed based on the energy conservation principle and the plastic hinge theory. The theoretical expressions of plastic bending dissipation energy, stretch dissipation energy and crushing force of the sinusoid corrugated tube were obtained during the crushing process. The results showed that the theoretical analysis results agree well with those of tests and numerical simulation; the mean crushing force is related to effective compression distance factor and amplitude factor; the normalized crushing force decreases with increase in wavelength and amplitude of the sinusoid corrugated tube, and increases with increase in amplitude factor.


  • DAI Gonglian1,2WANG Meng1 LIU Wenshuo1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 102-108.
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    In order to obtain deformation characteristics of a simply supported beam bridge with CRTS II ballastless track under dynamic loads, based on field tests, structural deformations of the track-bridge system were measured during CRH380A-001 train passing through a 32m long simply supported beam bridge with longitudinal continuous plate type ballastless track at the speed of 240 to 350 km/h. Through signals collecting on site and data analysis, vertical and transverse absolute displacements, horizontal break angle and beam-end rotary angle of the beam bridge structure, vertical and transverse relative displacements of the track structure and relative displacements of the pier beam were obtained. The resonance speed and dynamic coefficient of the bridge were studied. The results showed that under dynamic loads, the minimum vertical ratio of span to deflection of the beam is 54000, the minimum horizontal one is 150000, they are far larger than the minimum limit values in the code; the maximum values of the rotary angle at the beam-end and the beam horizontal break angle are 0.077‰ and 0.119‰, respectively, they are smaller than the limit values in the code; furthermore, the simply supported beam bridge with CRTS II ballastless track has the second-order vertical resonance velocity of 306km/h and the third-order transverse resonance velocity of 312km/h obtained with actual measurements, they agree well with the theoretical resonance velocities of 309km/h and 315km/h, respectively; the dynamic coefficient actually measured near the resonance velocity is bigger than the limit value of 1.084 in the code, its maximum value reaches 1.18.
  • ZHUJianmin, ZHOU Yanan, HEDandan, ZHENGZhouyang
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 109-115.
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    Aiming at the problem that dynamic characteristic parameters of sliding joints of a machine tool are difficult to identify accurately, here, a neural network modeling method for identifying sliding joints’ dynamic characteristic parameters was proposed. The model’s variables to be optimized were stiffness parameters and damping ones of sliding joints. With the calculation results of the neural network model and those of the machine tool test modal analysis, stiffness and damping parameter identification of the sliding joints was performed with the cuckoo optimization algorithm. As an example, modeling, tests and parametric identification were conducted for a self-designed and manufactured sliding guide joints between the working platform and the machine tool body. The results showed that the proposed method is feasible and effective; the parametric identification accuracy is higher than those recorded in literatures.
     
  • LI Yong-le,CHEN Ke-yu,WANG Bin,SUN Hao
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 116-122.
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    With increase in span, wind-resistant performances of bridges are more and more critical. Due to its superior flutter stability, separated twin-box girder has a broad application prospect in bridge construction. But its vertex-induced vibration (VIV) phenomenon is obvious. Although there are a lot of VIV optimization studies for separated twin-box girders, most of them are focused on good streamline type of box girders. The optimization study on VIV of bluff body separated twin-box girders is very scarce. Here, a certain bluff body separated twin-box girder bridge was taken as a study object, wind tunnel tests were conducted to study influences of aerodynamic measures, such as, guide vane, splitter plate and wind fairing on the VIV performance of the main beam cross-section to determine the optimal measure. The results showed that wind fairing can effectively suppress vertical and torsional VIV of bluff body separated twin-box girders; the smaller the wind fairing angle, the better its vibration-suppressing effect.

  • MA Deng-qiu1,3,WEI Yongqiao2,3,YE Zhenhuan1,HOU Li3,LUO Lan3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 123-131.
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    Taking circular arc tooth trace (CATT) cylindrical gears as a study object, in order to get CATT cylindrical gears’ mesh contact impact features, the mesh contact impact hypothesis of CATT cylindrical gears was put forward based on the contact dynamics theory and the gears transmission physical model to establish a gears’ mesh contact impact model. A finite element method was proposed to solve this contact impact problem. According to the tooth surface mathematic model of CATT cylindrical gears, the accurate 3-D digital prototype was established, then the dynamic finite element model to reveal the mesh contact impact process was built to study relations among impact velocity, impact location, impact stress, impact resultant and impact time. The results showed that impact velocity and impact location have a certain influence on impact stress, impact resultant and impact time. The study results provided a theoretical basis for dynamic design and industrial applications of CATT cylindrical gears.

  • ZHANG Qian1, GAO Mangmang2, MA Li2, XUAN Yan2,LI Hongmei2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 132-138.
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    Hu-Tong Yangtze River Bridge’s approach bridge adopts a 48m-long simply supported continuous beam bridge. When a train passes through this bridge at the speed of 200~250km/h, the deformation curve of the bridge is equivalent to continuous multiple excitations with a certain wavelength and a certain amplitude, the excitation frequency is near 1Hz and almost equal to the vehicle body’s natural frequency, the vehicle body resonance is easy to excite. In order to ensure the dynamic performance of 48m-long simply supported beam bridge satisfying the specified requirements, the safety and comfort of the train-bridge system during different trains passing through at different speeds were analyzed. The results showed that for the bridge, the vertical and lateral accelerations at the middle of span are lower than the limit value in the code except that the lateral acceleration at the middle of span exceeds the limit value in the code about 7% when SS8 traction double-deck passenger train passes through the bridge at the speed of 200km/h; for trains, their safety and comfort meet the specified requirements under all working conditions, so 48m-long simply supported beam bridge can ensure passenger trains safely and comfortably passing through at 120~250km/h; in addition, the characteristics of the track irregularity are equivalent to the track irregularity management level for the rank of 160km/h in China when the dynamic performance of the train-bridge system meets the specified requirements; comprehensively considering the analysis results and the level of railway operation and maintenance in China, the track irregularity management value for the rank of 160km/h is recommended as the track irregularity management criterion of this train-bridge system.
  • ZHU Mao-Tao1, TANG Wei1,WANG Dao-Yong2, YE Bi-Jun3, SHANGGUAN Wen-Bin2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 139-145.
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    A semi-active hydraulic shock absorber was designed and manufactured, and its dynamic characteristics were measured using MTS831. A fluid-structure interaction (FSI) method was used to build the dynamic model of this absorber and calculate its dynamic characteristics. The comparison between the calculated data and the measured ones showed that the error between the damping force of the absorber measured and that calculated is less than 15%, so the correctness of the absorber’s dynamic model built with the FSI method is verified. The influences of the absorber’s parameters, such as, oil viscosity and diameter of damping orifice on its dynamic performances were also analyzed. The proposed modeling method and test one provided a reference for further studying semi-active hydraulic shock absorbers.


  • YAN Zhi-tao1,2,WANG Ling-zhi2, LIU Jun2,YOU Yi2,3,SUN Yi1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 146-151.
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    The effect of cross-section shape of conductors on their aerodynamic characteristics is significant. Their bearing wind pressure is almost 50 to 70 % of the whole wind pressure of a transmission line. Aerodynamic characteristics and vortex-induced vibration (VIV) of real conductors with rough cross-section and those of conductors with smooth cross-section were analyzed using the numerical simulation method and   turbulence model based on RANS. The results were compared with those obtained with the test method. The fluid domain was meshed with ICEM. A 2-D circular cylinder in transverse flow direction’s VIV simulation model was established utilizing the dynamic mesh and sliding mesh model and embedding Newmark-β algorithm for structural response computation into the software FLUENT through the user define function (UDF) code. Aerodynamic and vibration characteristics of conductors under uniform flow and higher Reynolds number were studied with the variation of the reduced wind speed and Reynolds number. Simulation results showed that after considering conductors’ surface roughness, aerodynamic force and Strouhal number of fixed conductors drop; the range of conductors VIV’s "locked-in" region becomes wider and the vibration amplitude becomes larger; VIV amplitude of conductors with rough cross-section reaches 0.9D when the reduced wind speed is 5.766; aerodynamic force and vortex stripping mode of conductors with rough cross-section have larger changes, so the effects of surface roughness on aerodynamic characteristics of conductors are bigger.
  • WANG Xingdong1, LIU Cancan1,LI Yourong1, WANG Leichuan2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 152-156.
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    The coating quality of steel strip is seriously influenced by vibration of a sink roll immersed in molten zinc. It is necessary to study a sink roll’s liquid-solid coupled vibration. Based on the theoretical method of added mass, a mathematical model for the roll’s transient vibration responses considering effects of flow field was established. The on-line vibration tests for the roll were conducted. Combining the roll’s wet and dry modal analysis results, the added mass value was determined. According to the structural characteristics of the sink roll, the mass matrix of the mathematical model was modified, the numerical analysis model for the roll’s transient responses considering effects of flow field was established. The results of numerical simulation showed that the principal vibration frequencies in 3 directions of the model are close to the measured data, the effectiveness of the proposed method for liquid-solid coupled transient response analysis of the sink roll with an added mass is verified; based on this model, the transient responses of key regions including the contact surface between bearing and journal are obtained.
  • HUANG Hai-bo1, LI Ren-xian1, DING Wei-ping1, YANG Ming-liang1, CHEN Zhi-jun2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 157-163.
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    To quickly and accurately identify complicated and multi-correlated vehicle interior noise sources, a noise source identification method based on wavelet partial-coherence analysis was proposed. The approach was performed through the continuous complex wavelet transformation and the time-frequency partial-coherence analysis to get time-frequency partial coherence functions of noise source’s measured point and receiver measured point, and relations between them and transient phase. This was illustrated with simulated signals. The proposed method was utilized to identify an abnormal noise source in a vehicle, and then to improve the sound quality of interior noise with identified results. The results showed that the interior abnormal noise source is induced due to the engine exciting the front sub-frame to cause vibration and noise of the connecting point between the sub-frame and car body; through optimizing the connecting point rubber bushes, the subjective and objective evaluations of vehicle interior sound quality are improved evidently, the effectiveness of the proposed noise source identification method is verfied.
  • ZHAO Chenxiao1,LI Yingmin1,2,TAN Qian1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 164-171.
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    Long period component is a decisive one to reflect basic characteristics of long period ground motions (LPGMs). Based on Hilbert-Huang Transformation (HHT), in ground motion’s acceleration response spectrum, intrinsic mode functions (IMFs) with average period    2.0s and residual components were extracted to reconstruct a signal which was taken as the long period component of the original ground motion after baseline correction. The rationality of classifying a long period component was verified using the correlation analysis between the long period component and the original ground motion and effects of the long period component on structural responses of a super high-rise building. The long period ground motions indicator (LPGI) based on long period component characteristics was proposed, it was shown that the ground motion is LPGM when its  .The time interval needed for the area between the normalized Hilbert accumulated energy curve of a long period component and time axis to increase from 5% to 95% was proposed to represent pulse characteristics of LPGM. Thus the two kinds of special LPGMs including far-field LPGMs and near-field ones were distinguished. The results provided a better method and a parametric indicator for distinguishing LPGMs.
  • SONG Kai WANG Zhen ZHU Guohua CHENG Aiguo
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 172-178.
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    In order to improve energy absorption abilities of carbon-fiber composite cone tubes to make composite energy-absorbing components achieve the best effect of energy-absorbing in engineering applications, the structural optimization of composite cone tubes was investigated. The influences of ratio (α/N) of conical degree (α) to number of ply(N) on the specific energy absorption (SEA) and the initial peak impact load (Pinitial) were studied. It was shown that with increase in α/N, SEA and Pinitial are both reduced; when α/N exceeds 0.54, the delamination no longer occurs in crushing process. Finally, a composite cone tube was manufactured according to the optimization results,the optimal results were validated with tests. Test results showed that after optimization, the tube’s SAE increases 15.6% (from 67.9 J/g to 78.50 J/g), its Pinitial decreases 51.8% (from 52.3KN to 25.2KN), its mass decreases 22.4% (from 55.3g to 42.9g).
     


  • YUYan-junYE Qing-weiLU Zhi-huaZHOU Yu
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 179-185.
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    Empirical mode decomposition (EMD) is one of effective methods to process nonlinear and non-stationary signals, its key is to extract signals’ envelope curve. A method based on the sparse recovery optimizing algorithm was proposed to overcome defects of the envelope fitting algorithm, such as, end effect, bigger fitting error and low anti-noise ability, etc. Firstly, the concave problem of envelope sparse optimal model was converted into a convex quadratic programming problem by using exterior penalty functions. Secondly, the mixed variant particle swarm optimization (PSO) algorithm was used to solve the global optimization of the variant factor m which changes the sparse base’s frequency band width. This m was employed to build the optimal sparse bases being suitable for envelope variation trend. All extreme value points of the collected signal were taken as observed values in the process of sparse recovery. The optimal sparse bases and observed values were used to establish the sparse recovery model. The interior-point method was adopted to process the built model. Finally, the globally optimal envelope signal was gained adaptively. The results showed that this method can effectively suppress the end effect; PSO introduced here can adaptively match the mapping band width of the optimal spare bases, it improves the signal envelope fitting precision and noise immunity.


  • GAO Liang 1, YIN Hao 1, XU Yang 1,Yang Guo-tao 1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 186-192.
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    A sleeper-ballast-bedding surface coupled model was established with DEM to simulate the coupled action mechanism of ballast-ballast, ballast-sleeper, and ballast-bedding surface based on realistic appearance of ballast. The track structure loads-bearing characteristics, elastic and plastic deformation mechanism, and ballast bed/ bedding surface’s proportion under the condition of high-speed operation were studied deeply based on the model verified. The results showed that the track contact force shaped like a frustum is passed down, it extends below the syncline as a bevel; there are mutual invason phenomena of ballast-bedding surface, the proportion of ballast bed settlement is 83.9%~86.8%; track vertical elastic and plastic deformations and the proportion of ballast bed settlement increase nonlinearly with increase in train speed and train axle loads; the effects of train speed on track vertical deformation exceed those of train axle loads.
  • LI Xiao-bo1JiangZhinong1Zhang Pei1 Qian Di1Xue Jixu1 Zheng Hui1 ZHANG Jinjie1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 193-198.
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    Here, the IMS clustering algorithm was used to study fault diagnosis of diesel engines. Firstly, vibration signal features of a diesel engine were extracted, these features were selected. Finally, an IMS clustering algorithm model was established, the features extracted from fault data were taken as the model’s input parameters to realize diesel engine faults’ intelligent diagnosis. Test study was performed on a V6 turbocharged diesel engine to get data for both training purposes and verifying the IMS clustering algorithm model. Through verification of data, it was shown that judgements of the model for faults are correct. The study provided a new detecting way for fault diagnosis of diesel engines.


  • LIU zhe 1 TAO Feng-he 2 JIA Chang-zhi 2 MOU Peng-bo 3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 199-203.
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    Drive wheel is an important transmission component in a tracked vehicle chassis system, its strength has a certain uncertainty and is degenerative with time in actual operation process. Here, Gamma random process was used to describe the strength degradation process of mechanical components. Matrix differential method was used to derive sensitivity calculation formulas for mean and variance of mechanical components’ random variables. Taking drive wheel of a tracked vehicle as an example, the proposed method was verified. The results showed that the proposed method can effectively solve the sensitivity analysis problem for the reliability of mechanical components with strength degradation; the study results can be extended to the related machinery reliability optimal design fields with some practical significance.
     
  • ZHANG Zehua1,2 YIN Wensheng1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 204-210.
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    Aiming at lack of an accurate theoretical model for pneumatic membrane in a dual-chamber isolator, a theoretical modelling method for stiffness of pneumatic membrane was proposed here. The pneumatic membrane was divided into several parts according to their geometric shapes so that an irregular shape membrane’s whole stiffness modelling problem was converted into stiffness modelling of several parts with regular shapes. The composite material mechanics theory was used to get elastic modulus and stiffness of individual part made of anisotropic material. The pneumatic membrane’s whole stiffness model was deduced based on the stiffness relations among parts of the membrane. This stiffness model was verified with tests on a built test rig. It was shown that the results using the deduced stiffness model agree well with those of tests. This study provided a theoretical basis for the design of dual-chamber pneumatic isolators.

  • WANG Bo1 LIU Bo-quan1 Wu Tao1 DAI Hui-juan2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 211-219.
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    At present, there are no characterization parameters of characteristic period and intensity indexes of aseismic analysis for far-field long-period ground motion frequency spectra. Here, 40 far-field long-period ground motions were selected, and 12 types of representative frequency spectra’ characteristic period parameters and 20 types of intensity indexes for each ground motion were calculated using codes programmed with MATLAB. The characteristics of period parameters were analyzed based on the average value and variant coefficient’ calculation results of long-period ground motion frequency spectra’ characteristic periods. Besides, the correlations between intensity indexes and earthquake responses of far-field long-period ground motions were analyzed through calculating correlation coefficients between 20 types of intensity indexes and 5 types of maximum seismic responses including max acceleration, max velocity, max displacement, max input energy and max hysteretic dissipation energy of 400 single-DOF systems with two varying parameters of natural period and ductility factor. The study results showed that different period parameters reflect different frequency spectral characteristics, and their stabilities also have larger differences; Hilbert marginal spectral average period Tmh is suggested as the characterization parameter of characteristic period for far-field long-period ground motions; correlations between intensity indexes and maximum seismic responses are related to types of intensity indexes, natural periods and ductility factors; peak ground velocity PGV and peak ground displacement PGD have better correlations with maximum seismic responses under different natural periods, correlations grow with increase in natural period; so PGV and PGD are suggested as aseismic analysis intensity indexes for far-field long-period ground motions.
  • WANG Zhen-guo LEI Xiao-yan LUO Kun ZENG Shao-hui
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 220-226.
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    The similarity model of a simply supported box-girder bridge with span of 32 m was designed and made with the scale of 1:10. Based on the similarity law of elastic force, the similarity relation between the original bridge and the model bridge was derived. Taking the vibration of bridge structure as the study objective, the applicability of the similarity relation between the original bridge and the model bridge was discussed through the finite element (FE) numerical analysis and test study. The results showed that all physical quantities' scales between the original bridge and the model bridge obtained using the FE numerical analysis are basically consistent with those gained using theoretical deduction; there are differences between the measured data and those of the FE numerical analysis for the model bridge, but as a whole, both of them are roughly consistent; the similarity relation derived based on the similarity law of elastic force is applicable between the original bridge and the model bridge, however, it is needed to further verify if this relation is applicable for complex bridge structures.


  • WANG Zhiqiang,LI Xuebin,HUANG Lihua
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 227-232.
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     Free vibration of orthotropic circular cylindrical shells was studied based on Flügge classical thin shell theory and the wave propagation approach. The shells’ boundary conditions were simplified using those of beams. The free vibration problem of the shells was converted into a 6-order algebraic equation for natural frequencies to be solved. Through parametrically solving the solution space for free vibration of orthotropic cylindrical shells was obtained. The multivariate statistical method was used to analyze effects of geometric parameters and material feature parameters of the shells on their natural frequencies, and correlations among these parameters and natural frequencies. ANOVA was used to discuss influence levels of these parameters on natural frequencies. A knowledge and data visualization approach named Self-Organizing Mapping (SOM) was adopted to study features of the solution space. A numerical example was presented here. The study provided a general method for further studying vibration characteristics of orthotropic circular cylindrical shells with complicated boundary conditions and external loads.

  • ZHANG Rulin1 DI Qingshuang2 CHENG Xudong1 GUAN Youhai1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 233-239.
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    Based on Lagrange method, a modal equation of a storage tank considering fluid-solid coupled effect was established. 6 numerical models including soil free site, pile foundation platform model, rigid foundation empty tank, rigid foundation full tank as well as empty tank and full tank considering soil-structure interaction (SSI) were established with software ANSYS. Natural frequencies of the site and influences of soil-structure interaction on dynamic characteristics of a tank system were obtained using computation results of 6 numerical models. The distribution of natural frequencies and each modal shape’s participation coefficients of various models were studied. The results showed that the existence of pile foundation platform makes the site’s first order natural frequency increase; SSI does not affect the slosh frequency of liquid in tank; after considering SSI, 3 types vibration frequencies including liquid convective sloshing frequencies, soil-tank-liquid whole vibration frequencies and tank-liquid coupled vibration frequencies appear, the first two order tank-liquid coupled vibration frequencies decrease and are more dense; SSI effect should be considered otherwise tank-liquid coupled vibration frequencies are over-estimated. Finally, the sub-structure theory was used to explain changes of dynamic characteristics of a tank system due to considering SSI, the suggestion for choosing Rayleigh damping coefficient of a tank-liquid system considering SSI was given in dynamic calculation. The study conclusions provided a reference for seismic response analysis of storage tank systems considering SSI.
  • YANG Xiao-feng1,DU Yi1,LIU Yan-ling1,HU Jian-bin1,LIU Chang-ning1, XU Xu2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 240-246.
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    The influences of inertial mass coefficient on partial frequency and dominant frequency of inerter-spring-damper (ISD) suspension systems were studied. 10 effective ISD suspensions were presented based on different permutations and combinations of inerter, spring and damper, and working features of passive mechanical components. These ISD suspensions were classified into four types of undamped suspensions according to their undamped impedances. 3 types of undamped suspensions containing an inerter were studied. It was found that partial frequency and dominant frequency numbers of these 3 types of undamped suspensions are obviously different due to effects of inerter mass impedance and new mechanical network’s topological characteristics. Simulation results indicated that partial frequency and dominant frequency of various suspensions can be reduced with increase in inertial mass coefficient to make their dominant frequencies be away from the most sensitive frequency range of human body in the vertical direction; furthermore, influences of inertial mass coefficient on partial frequency and dominant frequency of suspensions gradually decrease with increase in inertial mass coefficient.
  • XU Guo-min1,2 ZHOU Wei1,2 HE Lin1,2SHUAI Chang-geng1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 247-253.
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    Air springs are nonlinear vibration isolators with variable stiffness and natural frequency unvarying with loads. Cuboid air springs have a higher space-utilizing rate than conventional rotator air springs do. Here, based on the existing theoretical studies on dynamic characteristics of rotator air springs, considering influences of system natural frequency on polytropic exponent and vertical dynamic characteristics, a nonlinear stiffness model of air springs was established and the vertical stiffness calculation formula was extended. The conceptual adiabatic frequency threshold was proposed. A new cuboid air spring was designed and tested. Test results agreed well with those of theoretical prediction. Compared with the dynamic features of commercial air springs, it was shown that the new designed cuboid air spring has advantages of a larger load-bearing ability and a higher space-utilizing rate. 


  • LUO Zhu-hui,HE Cai-chun,LUO Yi-ke, ZHOU Xi-sheng, YAN Meng, GUO Fu-ling,
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 254-258.
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    Engine noise is the main noise source of passenger cars. Inner-dash insulator plays a very important role in obstructing engine noise transmission from engine to passenger compartment. According to the sound insulation test principle of insulation material using the reverberant room-anechoic room method, a simulation analysis calculation model for sound insulation performance of inner-dash insulators with EVA layer and PU one was built in LMS Virtual.lab. It was shown that the difference between the simulated results and test ones is 0.5dB~2dB within the frequency range of 315Hz ~ 2000Hz, the simulated results meet engineering requirements. Using the simulation analysis method and model, sound insulation values and sound insulation efficiencies of 12 types of inner-dash insulators were computed. The results showed that the insulator with EVA thickness of 2.5mm and PU density of 50kg/m3 has the maximum sound insulation efficiency; this insulator can be taken as the optimal design scheme of inner-dash insulators. This conclusion was verified with sound insulation test results of inner-dash insulators.  .


  • FU Junfan1,QIN Huibin1,LV Ming2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(7): 259-266.
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    An ultrasonic longitudinal-flexural resonance transducer is consisted of a horn and a stepped annular plate with multi materials, and applied on ultrasonic machining and ultrasonic treatment. In order to design longitudinal-flexural resonance transducer with rapidness and accuracy, a design method for transducers was proposed with Mindlin theory. Based on Mindlin theory, formulae for displacement, rotation angle, bending moment, and shear force of moderately thick annular plates may be obtained. By continuous and boundary conditions among vibrating elements, vibration model and equations of longitudinal-flexural resonance transducer can be established. In view of the vibration model, a design software for the transducer is developed with Matlab/GUI. Two longitudinal-flexural resonance transducers were designed theoretically. Finite element analysis, impedance experiment and ultrasonic resonance experiment of the transducers were carried out. Results proved that resonance frequency of transducers designed by this design method was in a good agreement with design frequency. The design method showed high design accuracy, and can provide reference for transducer design.