25 January 2011, Volume 30 Issue 1
    

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  • Zhang Bing-qiang;Li Liang
    . 2011, 30(1): 1-5,15.
    Abstract ( 1798 ) Download PDF ( 821 )   Knowledge map   Save
    The human body is simplified as the parallel dynamic model and the vehicle as the seven-freedom vibrating model. The road is supposed as the Euler Beam on the Kelvin base. And then base on the compatibility deformation condition and the interaction force between the road and the vehicle, the dynamic functions of the body-vehicle-road coupled system are derived. The functions are been divided and solved with mode synthesis method and New-mark method. The process while the vehicle is running on the road is simulating, and the riding comfortable is analyzed with the synthetic comfortableness. It proffers the thereunder that the comfortableness can evaluate road roughness. And also the effects of the vehicle parameters, vehicles velocity, road surface class and the amount of passenger on the vibration of the system are also analyzed.
  • XU Wei;HE Lin;SHI Liang
    . 2011, 30(1): 6-10.
    Abstract ( 1196 ) Download PDF ( 594 )   Knowledge map   Save
    When marine main engine is mounted on air springs, its vibration transmitted to ship hull can be greatly attenuated. But it is more difficult for the main engine to keep alignment with the propulsion shafting. During its operation, the main engine is subject to various disturbances which increase misalignment. So it is important to control these alignment disturbances. By charging and deflating air springs, the misalignment induced by disturbances can be effectively controlled. The control strategy is presented in this paper. And the disturbance control effect is analyzed based on the experiment data of a main engine air spring mounting system.
  • XIE Quan-min;LONG Yuan;ZHONG Ming-shou;LIU Hao-quan;ZHOU xiang
    . 2011, 30(1): 11-15.
    Abstract ( 1050 ) Download PDF ( )   Knowledge map   Save
    Based on the comparability of wavelet packet and fractal technology, wavelet packet and fractal combination technology is proposed to analyze blasting vibration signals. Using wavelet packet to decom-pose blasting vibration signals, through the analysis of the main wavelet packet reconstruction coefficients of blasting vibration signals, the fractal characteristics were verified, through the analysis and comparison to the box-counting dimension of the main wavelet packets, the fractal dimension changes of different blasting vi-bration signal frequency components can be analyzed further. The combination analysis shows that, box-counting dimension changes with wavelet components frequency of blasting vibration signals,so we put the box counting dimension as an important parameter, which reflect frequency characteristic of blasting vi-bration signals. Wavelet packet and fractal technology will provide us new ideas for the fractal features re-search of blasting vibration signals.
  • Ma Qianying;Wang Sheliang;Zhu Junqiang;Cao Wei
    . 2011, 30(1): 16-20,3.
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    Using intelligent materials for the structure seismic active control is a new frontier, the current research is mostly confined to the single component or theoretical derivation. Considering the complexity and discrete of the structures, experimental study is necessary. Based on a three-layer intelligence space structure active control experiment, the paper design the driving lever, and optimize the layout position and gain value;The research shows that active control effect close relations with the structural parameters and layout position, but with no difference because of the different seismic wave; Through the active control, the peak value of displacement and acceleration for each layer, especially the most severe which got greatly restrained; the optimization based on genetic algorithms is efficient and the global optimization.
  • Tian Zhimin;Wu yubin;Luo Qifeng
    . 2011, 30(1): 21-26.
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    Propagation of air shock wave inside a tunnel induced by internal explosions and distribution law of shock wave load on inner surface of the tunnel are studied in this paper. The flow fields of shock wave inside a tunnel with and without end walls are described on the basis of three-dimensional finite element analysis. Distribution laws of peak reflected overpressure (i.e. peak load) and impulse on inner surface of the tunnel are analyzed. Influences of shape and explosion height of TNT explosives on propagation of shock wave and the load are taken into account. The formula to evaluate attenuation of peak value of reflected shock wave load on inner surface of the tunnel with distance from the center of explosion is proposed.
  • FU Chunyu;SHAN Deshan;LI Qiao
    . 2011, 30(1): 27-32.
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    Based on the correlation between bridge’s damage state and train load when the train is running on railroad bridge, the time domain method for bridge structural damage alarming is put forward. Firstly, structural damage sensitivity is analyzed to find out the vulnerable sections in this method. Then right subdomains are selected from the time domain when the train is running on railroad bridge, owing to the damage state of the vulnerable sections. At last, by using the acceleration time domain data as damage index, support vector machine, one of pattern recognition methods, is used for damage alarming in every subdomain. A continuous girder is analyzed, and the results show that this method has a preferable capability of identification and noise resistance.
  • HUANG Yanlin;LI Yourong;XIAO Han;LV Yong
    . 2011, 30(1): 33-36.
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    The noise problem exists in Failure Analysis of the signal. Local independent projection de-noising algorithm combinated phase-space reconstruction and independent component analysis is introduced.Phase-space reconstruction can restore the chaotic attractor from high dimensional phase space.Independent component analysis can find the mainstream of the signal shape.Neighborhood can combinate the phase of similar to the feature.This method tests simulation experiments on sinusoidal simulation signal and Lorenz simulation signal,the result shows that the noise reduction effect of Local independent projection analysis is similar to that of local independent component analysis,but better than that of golbal projection algorithm.Low speed and heavy loading bearing vibration signal uses this method and the fault is identified accurately.
  • MU Jin-lei;ZHU Xi;HUANG Xiao-ming;BAI Xue-fei
    . 2011, 30(1): 37-39,5.
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    The crevasse of clamped square plates under near-field noncontact underwater explosion is studied in this paper. According to conversation of energy, the energy of shock wave translate to the initial kinetic energy of the plate, and then translate to the distortion energy. By means of supposing a certain mode of distortion, the relations between the distortion energy and the angle of the plate are obtained. Therefore, the angle of the plate can be obtained. After the appearance of the damage at the center of the plate, the cracks extend toward to edges, like the leaves, till the ring strain equal to the fracture strain. Then the crevasse get maximum. According to the angle, the size of the crevasse can be obtained. Compared with the results of the FEM software ABAQUS, the theoretical results are believable. So the method of this paper can be used to estimate the crevasse size.

  • QIU Liang;JIANG Zhe
    . 2011, 30(1): 40-43.
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    The sound power minimization design with weight restrict is studied for reducing noise from vibration of a thin plate. By use of finite element vibration model to deal with vibration of the structure and acoustic radiation modal model to deal with radiation, the optimization design is investigated by the feasible direction method. The sound power minimization model with damping weight restrict is established for a rectangle viscoelastic damping plate. Results show that the optimal design with weight restrict has remarkable efficiency on reducing noise.
  • Luo Jianfei;Wu Zhongcheng;Shen Fei;Shen Chunshan
    . 2011, 30(1): 44-48.
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    In view of the present vibration signal detecting system's insufficiency, this paper designed one kind of vibration detecting system based on ARM and Accelerometer。The system induced the multi-channel vibration acceleration signal and completed signal filting, acquiring and analysis processing. The system was composed by sensor part, data acquisition part, micro- processing part and computer system. The micro-processing part used LPC2129 as the core embedded micro-processor and the data transmission used the reliable stable CAN protocol to make the data transmission accuracy. The system selected the USB power supply method and the structure was compact and well operation. Finally the system is validated by the example of Human Body Dynamics.
  • ZHAO Xue-zhi;YE Bang-yan
    . 2011, 30(1): 49-55.
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    Generally a normal distribution random sequence is generated by a single seed, but in fact each random number in this sequence can also be generated by different seeds. The method to generate different seeds is put forward and the measure to avoid generating same sequences when random number generator is transferred continuously is proposed. Four statistical parameters being used, the qualities of a great lot of normal random sequences, which are generated by single seed and multi-seed methods respectively at different time, are contrastively studied in the aspects of normality, mean, deviation and randomicity by virtue of statistical simulation and hypothesis test theory. The results show that random sequences generated by multi-seed method have the evident advantage in normality and deviation quality, while in mean and randomicity quality, the effect of these two methods are basically same to each other, so as a whole, the multi-seed method is better than the single seed one.
  • Tao Meng;Tang Weilin
    . 2011, 30(1): 56-60.
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    The axisymmetric wave propagating along the thickness direction of Alberich sound absorption coating is excited in the case of normal incidence, and the axisymmetric wave with the lowest order which determines the low-frequency performance of sound absorption can be approximated as a quasi plane wave. The mechanism of sound absorption of Alberich coating is analyzed by using the resonance theory, and the relationship between the phase velocity of axisymmetric wave and the lowest peak frequency of absorption coefficient is obtained. The mechanisms of sound absorption at low-frequency include that: (1) the coating resonance is referred to the resonance of viscoelastic cylindrical tube; (2) the peak frequency of absorption coefficient is corresponding to the anti-resonant frequency, rather than resonant frequency of coating; (3) the lowest peak frequency of absorption coefficient in the case of soft backing is half of that in the case of rigid backing.
  • Xiaobing Wang*;Yinghua Liu;Jianjun Chen
    . 2011, 30(1): 61-68.
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    For the robust H∞ vibration control of high-order complicated uncertain system, based on the study on the reduction of uncertain system with small interval parameters, a research strategy and analysis method is presented, which includes the construction of the system to reduce, reduction of uncertain system, the solving method of robust controller and the verification of robustness, and so on. In order to ensure the whole process of analysis and calculation going well, the calculation of the first order partial derivatives of high-order matrix exponential is studied and a decomposing form of uncertainty matrix with lower dimensionality is given. Finally, the rationality and feasibility of the suggested method is proved by numerical examples.
  • Yanbin Liu and Yushu Chen
    . 2011, 30(1): 69-72,1.
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    The Taylor series of Melnikov function is used to study the bifurcation of nonlinear systems with high codimension in this paper. The method is approved feasible by analyzing the generalized codimension-4 Duffing-Van der Pol equation. The results shown that there is the phenomena of multiple limit cycles, limit cycle and heteroclinic loop, heteroclinic loop are possible. Finally the numerical solutions are given to show that the analysis results are correct.
  • Luo Zhigao;He Xin;Xu Aichen;Chen Qiang;Chen Peng
    . 2011, 30(1): 73-76.
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    As the Complexity of compound abnormal signal of rolling bearing, this article uses the local time frequency characteristic of Gabor wavelet to extract the characteristic parameters from the obtained signal, then the possibility theory in fuzzy mathematics was taken as the foundation to obtain the membership function of characteristic parameter. Last the successive fault diagnosis method was used to research the rolling bearing compound fault diagnosis. The experiment shows this method can be applied well in rolling bearing compound fault diagnosis under the changeable condition.
  • Xia Tian;Wang XinQing;Zhao HuiMin;Liang Sheng
    . 2011, 30(1): 77-81.
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    Since the method of high order cumulation can not be used on-line because of longer computing time required, a new method using 1.5, 2.5 dimension spectrum is proposed to analyze vibration signals caused by difference crankshaft bearing clearances and extract the fault features of the crankshaft bearing. This new method holds the high order cumulation’s features in suppressing noise and extracting nonliner coupling characters. When vibration signals was acquired, vibrant sensor was fitted in 4 different position and the sum of energy of some frequency band was extracted as fault features. Experimental result shows that parameters present in this paper show the working conditions of crankshaft bearing much exactly, when the speed of engine is higher than 1300 r/min, the best diagnosis area for data collecting is the two side of the areas between the cylinder and the bottom of the engine.
  • Xiao Yanping;Yang Yi-ren;Ye Xian-hui
    . 2011, 30(1): 82-86.
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    Based on the Kelvin' s viscoelastic damping model, the flutter differential equations of a three dimension panel are set up according to Von Karman large deformation strain-displacement relation and the first piston theory of supersonic aerodynamics by using the Galerkin approach, which are solved with Rouge-Kutta method. The effect of viscoelastic damping, in-plane loads and panel length-to-width ratios on the flutter of the panel are analyzed. Then Using dynamic pressure as bifurcation parameter, its bifurcation and chaos behaviors are studied. The results show that with the rise of viscoelastic damping, the stable region increases firstly and then decreases; and the chaotic region fleetly decreases; but it is almost no effect on buckle region. The results also demonstrate that with variation of bifurcation parameter the viscoelastic panel flutter system may represent complex dynamics characteristics. It changes to simple harmonic limits cycle oscillation from the chaotic oscillation through a series of bifurcations. And the more compression in-plane loads and the smaller length-to-width ratio are no benefit to the stability of the panel.
  • Tao Meng;ZHUO Linkai
    . 2011, 30(1): 87-90.
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    In the case of normal incidence, the acoustic performance of sound absorption coating is analyzed by using ANSYS software. The relationship between the damp item in the ANSYS code and the loss factor of material is obtained. The acoustic performances of sound absorption coating which contains periodically distributed cylindrical cavities are evaluated by both ANSYS code and two-dimensional analytic model, and good agreements show the applicability of ANSYS code. Furthermore, regarding the cell as a viscoelastic cylindrical tube is accurate enough in the two-dimensional analytic model.
  • Shen Xiumin;Zuo Shuguang;He Lvchang;He Rong;Chen Ruifeng;Zhang Jingfen
    . 2011, 30(1): 91-94,1.
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    In this paper, fuel cell vehicle (fuel cell vehicle, FCV) is focused on as the reserch object and the sound signals collected in different locations at idle condition as the experimental samples. This paper uses paired comparison method to have subjective evaluation test for the 24 signal samples stated above, meanwhile, it calculates the six parameters of objective evaluation describing the sound characteristics and adopts BP neural network to establish FCV sound quality prediction model, which could be uesd to calculate the impact weight that means how objective evaluation of sound quality parameters impact on the results of subjective evaluation. It is the first time to propose to use the method of BP neural network to determine impact weight measuring objective evaluation parameters contributing to the results of subjective evaluation in the process of sound quality evaluation, then it is obtained main objective parameters determining sound quality good or not. This analysis, in both fuel-cell vehicle and other areas for sound quality evaluation and analysising, plays a significant guiding role.
  • LI Lin;ZHANG Yongxiang
    . 2011, 30(1): 95-97.
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    Aiming at the disadvantages of the excisting methods of indicated torque estimation,a new method is brought out based on instantaneous speed according to the kinetic model. A new concept is bring into the method brought out in this paper——synthetic acceleration, to eliminate the effect of the non-linear part in the model. Regarding the synthetic acceleration as input and the indicated torque as output, the armax model is used to build the transfunction, so the indicated torque estimation based on instantaneous speed is realized.
  • XIAO He-ye;SHENG Mei-ping;WU Wei-hao
    . 2011, 30(1): 98-101.
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    Vibration model of new type of broadband dynamic vibration absorber, which is a composite beam with rubber layer in variable cross-section, coupled with plane is established by theory of power flow. While the minimize of the maximum peak of pure power flow input to structure which is controlled by absorber is specified as goal function, particle swarm optimization is used to optimize the parameters of broadband dynamic vibration absorber, then scale of the parameters of dynamic vibration absorber which greatly decrease the vibration of target structure is summarized. After comparing with the results of experiment,conclusion is obtained and shows that particle swarm method is suitable for analyzing the complex continuous absorber optimization.
  • ZHANG Guo-dong;CHEN Fei;JIN Xing;LI Yong;LI Rong-bin
    . 2011, 30(1): 102-105,.
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    The boundary condition of the limited computing domain is key problem of dynamic finite element calculation. This study, using the nonlinear dynamic finite element method, investigates the seismic behavior of the slope. The boundary condition modeled in the dynamic analysis is summed up in five cases. The three actual seismic wave are inputted. The dynamic responses (displacement, acceleraction and frequency spectrum) of the slope are evaluated on the basis of the different boundary conditions and seismic wave. This paper shows that dynamic responses of the slope have significant difference. The research helps to further reveal the seismic properties of the slope, and to lay foundation for analyzing slope failure mechanisms and improving the reliability of slope stability analysis and evaluation.
  • HAN Dongying;ZHOU Guoqiang;LI Zifeng;SHI Peiming
    . 2011, 30(1): 106-110.
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    In order to forecast the ultimate bearing capacity of derrick steel structures, two novel methods are proposed based on kinetic parameters identified from vibration measurement. Aiming at the design feature and force characteristic of derrick steel structures, it is simplified freely supported beam. According to the relations between load and frequency, the expression for ultimate bearing capacity determined by frequency is deduced. This method is easy and feasible and the system model needn’t be built. The first order optimization is used for updating the dynamic model in the second method, and then the linear buckle, nonlinear and double nonlinear analysis are carried out to evaluate the ultimate bearing capacity. This method is more complex, but accuracy. At last, the dynamic test of some type of derrick steel structures is carried out using approximate stationary random motivation. The ultimate bearing capacity is obtained by the two mentioned methods. The results show that the relative error is small, which also indicates that the ultimate bearing capacity can be forecasted accuracy by these two methods. These methods also offer an effective way for the ultimate bearing capacity forecast and safety evaluation for complex load carrying steel structures.
  • Bian Yixiang;Qiu Jinhao;Wang Xinwei
    . 2011, 30(1): 111-115.
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    The metal core piezoelectric fiber (MPF) is one of the new type piezoelectric devices for sensors and actuators. When an external harmonically varying voltage is applied on the electrodes of a cantilevered MPF, it will cause longitudinal vibration. The equal external force can be driven from the strain in the piezoelectric elements that caused by the electric field. Using the vibration theory of a cantilevered bar, the longitudinal vibration equations can be given for the MPF as a cantilevered bar. The electric displacement can be derived by the constitutive equations for the piezoelectric element. And the electric charges on the electrodes can be driven by integrated over the surface of electric displacement. The total current flowing into the electrode surface and the admittance of the MPF can be derived from the electric charge. Using the resonance frequency, the elastic coefficient at a constant electric field can be driven from the admittance. And using the antiresonance frequency, one can get the electromechanical coupling factor . The dielectric permittivity at a constant stress can be extracted by the lower capacitance. Using above parameters, the piezoelectric coefficients can be calculated. One experiment was performed. The theoretical simulations and experimental results show that this method is accurate and available to measure the properties of MPF.
  • WAN Guo-xiang;WANG Qi-sheng;LI Xi-bing
    . 2011, 30(1): 116-120.
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    The experiments were made on the SHPB system and the AE law of rock under stress wave is obtained. The experimental results show that, the AE signals are few before the peak of the energy; and the AE energy presents two different features: I mode, the energy decays rapidly after the peak of the energy, however, the energy rises at the end of the loading and the “inflection point”appears; II mode, the energy decays slowly after peak energy and the “inflection point”does not appear. The research results indicate that the AE energy features closely relate to the rock fragmentation degrees; the AE under stress wave is not only the reflection of the cracks, but of the stress wave signals.
  • LI Ling-;SONG Gui-qiu;MA Yuanyuan;WEN Bang-chun
    . 2011, 30(1): 121-123,.
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    First, using harmonic response analysis the Motor coach of CRH to get the body structure harmonic response characteristics in the range of 0~100Hz. and get the value and frequency response curve which related to the passengers’ traveling comfort, get the Human Body inherent sensitivity of the vibration characteristics frequency bands in the harmonic load after contrasting in different parts of the body or the natural frequency of the Human Body system. Then using the track irregularity as an example, analysis random vibration (PSD) to forecast the structural response when be based on incentives in the actual operating condition, and analysis the frequency ranges and reasons which affecting passengers traveling comfort in the actual running condition.
  • WU Xiao;SUN Jin;Huang Chong;Lou You-xin
    . 2011, 30(1): 124-127.
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    The dynamic responses of the foam metal aluminum alloy beam was studied by Timoshenko beam corrective theory. The vibration equation of it was established by Timoshenko beam corrective theory, the expression for natural frequency of it and the analytical solution for forced vibration of it under the action of harmonic load were obtained.The comparative analysis of the spherical foam aluminum alloy beam and another foam aluminum alloy beam was carried out by practical calculation,and it was summarized that the spherical foam metal aluminum alloy beam had the better dynamic performances than others.
  • TANG Bao-Ping;LI Feng;CHEN Ren-Xiang
    . 2011, 30(1): 128-131.
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    A new fault diagnosis model is proposed based on Littlewood-Paley wavelet support vector machine(LPWSVM): firstly, fault vibration signals are decomposed into several stationary IMFs, then the instantaneous amplitude Shannon entropy of the IMFs which have fault modulation characteristics is computed and regarded as the input characteristic vector of LPWSVM for fault classification. EMD decomposition adaptively isolates fault modulation signals from original signals. The distinction among instantaneous amplitude Shannon entropy vectors enlarge the differences among fault types. Littlewood-Paley wavelet kernel is a new multivariable support vector kernel function,which has orthonormal feature, and can approximate almost any function in quadratic continuous integral space. Thus it has favorable nonlinear mapping ability. Compared with LS-SVM under the same conditions, the learning precision and adaptive diagnosis capacity are improved by LPWSVM. Therefore,it will be more suitable for complicated pattern recognition. The rolling-bearings fault diagnosis example proves the effectivity of this new model.
  • LiuChunguang;Jia Lingling
    . 2011, 30(1): 132-136.
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    As model test is an effective method to study the characteristics and mechanism of ice-induced vibrations of structure. In this paper, based on a modified similitude law, a laboratory test is performed for the simulation of ice-induced vibrations of a pier structure , in which DUT-1 model ice sheet are driven by the trailer at different velocity. Both the ice sheet time histories and the response of pier are measured. According to the test phenomenon and measured results, some valuable conclusions are obtained. Therefore, this ice- induced pier vibration model test can provide references for the progress of real ice engineering in cold area., and is a suitable way to study the ice-structure interactions and ice-induced vibration . It also can make the model test develop more perfectly.
  • Sha Yundong;Guo Xiaopeng;Liao Lianfang;Xie Lijuan
    . 2011, 30(1): 137-141.
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    The vibratory fatigue of some complex thin-walled structures undergoing random acoustic loadings is typically of multiaxial fatigue problems, and it is an effective approach to conduct the multiaxial fatigue damage analysis with Von Mises stress criterion. The probability distribution of Von Mises stress is investigated in this paper for structures under band-limited Gaussian white noise loadings. The hypothesis are proposed that Von Mises stress obey two-parameter Weibull distribution or Lognomal distribution, and the method for estimating the parameters of the two kinds of probability distribution are developed. As a result, the peak value probability desenty functions of Von Mises stress can be calculated, and these functions can be used as the basis for estimating the structural fatigue life. In the engineering application, by using coupled FEM/BEM method, the power spectrum density (PSD) of the vibrational stress response of thin-walled structures of an aeroengine combustor liner under random acoustic loadings is calculated, the probability distribution charactoristics of Von Mises stress are analyzed emphatically, and the results are comparetively validated by Kolmogorov-Smirnov(K-S) test.
  • Zhang Ben-jun;Wang Rui-lin;Li Yong-jian;Li Zhi-yong
    . 2011, 30(1): 142-144.
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    The structural of machine-gun mount should be optimized to improve firing accuracy. There is some limitation in structural optimization based on CAE software, so a new method that combines BP neural networks with genetic algorithms is presented. The structural of machine-gun mount is optimized in this paper based on the method and finite element of machine gun. The result shows that the new method can be used in multi- variables of machine-gun mount’s optimization, and it supplies a new method for other complex structure’s optimization.
  • . 2011, 30(1): 145-147,.
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    Taking pulsating water pressure of the stop log gate as an example, S transform was adopted to analyze pulsating water pressure signal recorded in time –frequency domain, the energy distribution laws in time –frequency and the dominant frequency of pulsating water pressure signal were investigated. The resonance in the working condition was judged though comparing the frequency of pulsating water pressure and the natural frequency of stop log gate. The results show that the frequency of pulsating water pressure is low and changing as the time go on; The frequency components have obvious change in different intake schemes, the pulsating energy and the frequency components are more and more abundant with the increasing intake altitude. The frequency of pulsating water pressure is less during the process of outlet than the stop log gates, so the resonance can be avoided.
  • QI Huan-huan;XU Jian
    . 2011, 30(1): 148-151.
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    : Two methods, Galerkin method and complex mode method, are developed to analyze natural frequency character of cantilevered pipe conveying fluid system at different flow rate. The influence of Galerkin modal truncation to natural frequency results is analyzed. Firstly, complex mode is used in a simplified cantilevered system, then the complex transcendental equations are solves by secant method, and the natural frequencies are obtained as flow rate varying. Secondly, the first N-order natural frequencies can be obtained approximately by Galerkin method which discretizes partial differential equations into ordinary differential. Finally, comparing the results that obtained by two methods, we can found that a sufficient exact appropriate model can be build by Galerkin method truncating appropriate mode, what facilitates control system designing and engineering practice.
  • YAN Shu-ming
    . 2011, 30(1): 152-156.
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    In order to do feasibility analysis of barrier safety evaluation with finite element simulation method, various vehicle and barrier finite element simulation models were set up and compared to multiple physical test data. The results indicates that all barrier safety index such as test vehicle trajectory, safety barrier performance, occupant risk and barrier dynamic deformation can be extracted from simulation result, the reliability of simulation models are proved for the crash results in simulation is coincident with that in test and the error is less than 10% between them, and the feasibility of barrier safety evaluation with computer simulation methods is proved. The concept that simulation model to evaluate barrier safety performance must pass crash test checking is stressed and the suggestion that regulations and guidelines on CAE engineers engaged in barrier simulation evaluation is brought out.
  • Zhang Jin;Feng Zhipeng;Chu Fulei
    . 2011, 30(1): 157-161.
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    The impulses in vibration signals and their spectral features are important in diagnosing localized damage of gears. A new method, so called time-wavelet energy spectrum, is proposed for gear fault diagnosis. It can extract the feature of impulses in both time domain and frequency domain. It is applied to analyzing the vibration signals of a gearbox under normal, worn and tooth broken statuses. The comparison with traditional spectral analysis shows that: the time-wavelet energy spectrum is effective in extracting the impulse features produced by localized gear damage, and thereby in recognizing and locating the gear faults.
  • Wang Hao;Cheng Yuansheng;Liu Jun;Li Rongfu
    . 2011, 30(1): 162-166,.
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    A new kind of rectangular honeycomb sandwich stiffened cylindrical shell is proposed. The responses and shock‐protection
    mechanism of this new structure are analyzed. In the study, the commercial code LS‐DYNA is employed to analyze the dynamic
    responses of this new sandwich structure subjected to underwater explosion shock load. The largest deformation and plastic strain of
    pressure hull are selected as the indicators to evaluate the effects of typical parameters on the anti‐shock performance of the structure.
    At last, the anti‐shock performance of a typical honeycomb sandwich stiffened cylindrical shell in different shock environment is also
    investigated.
  • Zheng Xu;Hao Zhi-Yong;Jin Yang;Lu Zhao-Gang
    . 2011, 30(1): 167-170.
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    An adaptive generalized S transform (AGST) is introduced in this paper. The simulation shows that the time-frequency resolution obtained by AGST is better than S transform and STFT. Then, the proposed method is introduced to analyze the vibration characteristics of the cylinder head of a four-cylinder IC engine. The result indicates that time-frequency representation obtained by AGST method has a better time-frequency resolution than S transform, and could exactly reveal the vibration characteristics of the internal combustion (IC) engine cylinder head. The research achievements could provide guidance for the following research of the vibration control and structural optimization for this IC engine.
  • Fan Shilei;Zhang Junjie;Li Xiaofa
    . 2011, 30(1): 171-174.
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    The aeroelastic stability requirements of the airworthiness standard for transport category airplanes(CCAR25.629)prescribe that icing on wing surfaces is one of the failures,malfunctions, and adverse conditions which must be considered.The compliance with the airworthiness standard must be shown by wind tunnel test and theoretical analysis.For a certain civil airplane,wind tunnel test was carried out to simulate different ice accumulation expected on wing surfaces. Schlipp’s Method was used to extrapolate the flutter speed.And research was did to analyze different icing conditions.The result of test and analysis shows that,the flutter form under the icing condition is the coupling of wing’s bending and wing’s torsion;ice accumulation on wing surface has no adverse influence on aeroplane’s flutter speed;and this type of aeroplane can satisfy the request of the flutter envelope.
  • Guo Jinku;Wu Jinying;Zhang Qian
    . 2011, 30(1): 175-179.
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    In this paper, a novel algorithm for parameter estimation of multicomponent chirp signal in complicate noise environment is proposed. By the matching pursuit algorithm, the signal is first decomposed into Gabor atoms which provide sparse information that represent the signal time-frequency signature. Hough transform is then directly used to estimate chirp rate, start frequency and stop frequency of chirp components without computing the time-frequency distribution. Simulation results show that this algorithm is capable of estimating parameters of multicomponent chirp signals even in the presence of powerful intended interference and colored noise. Comparing to other techniques, the algorithm is computational efficient and makes it possible to apply in real-life problems.
  • Gao Chen;FANG Zong-de;LIU Lin-hui
    . 2011, 30(1): 180-182.
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    Based on ANSYS,we established a 5 tooth contact model of Cylindrical Helical Gear with hole,developed a program of automatic generation three-dimensional finite element grid. In order to minimize the bending fatigue principal stress of Tooth root,we build a quadratic on ansys results by RSM and optimize the parameters of drilling, which would provide an accurate and effective Reference on structural design and improvement.
  • LIU Hongxi;ZHANG Fang;PANG He;Ding Bo
    . 2011, 30(1): 183-187.
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    To improve welding characteristics of CO2 arc welding, sedan split case and sleeve were welded by conventional CO2 arc welding, conventional CO2 arc welding combined with vibration aging and vibration CO2 arc welding processes. The welding seam residual stress and microscopic structure at various welding conditions were also investigated. The experimental results indicated that vibration CO2 arc welding can reduce welding deformation and residual stress in the cases of proper vibration parameters, resonance frequency and higher vibration amplitude. The highest von mises stress decreases by 41.74%. Weld bond zone and transition zone of vibration CO2 arc welding is more narrower compared with the conventional CO2 arc welding. The crystalline grain in welding seam and heat affect zone (HAZ) become smaller. The microscopic structure changes from columnar grain to equiaxed grain,and the widmanstatten structure decrease even disappear increasingly.
  • WANG Jun;LU Li-xin;WANG Zhi-wei
    . 2011, 30(1): 188-190.
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    The shock characteristics of cubic nonlinear stacked packaging system with critical components were investigated under the action of half-sine acceleration pulse.The dynamical model of the system was developed, and the numerical results of the dynamical equations were obtained. Then, to evaluate the damage potential of shock to the critical components of the system, a concept of combined shock response spectrum was proposed.Based on the results,the effect of peak pulse acceleration,mass ratio, frequency ratio, damping ratio of critical component and cushioning pad in addition to the number of layers on the combined shock response spectrum of the system was discussed.
  • . 2011, 30(1): 191-196.
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    Based on the rigid multi-body simulation, the Z axis feed module of a new type of turn-mill combined machine tool is studied considering the flexibility of plate and contact interface. A rigid-flexible model of the Z axis module is established and verified by the sine sweep experiment. Furthermore, by considering the linear motor servo control loop, a modeling method which can study the dynamic charac-teristic of the feed drive system under the influence of rigid-flexible& electrical-mechanical coupling is presented. The simulation results illuminate that the mechanical structure and the servo control loop have a corporate critical influence on the dynamic characteristic of the feed drive system of the machine tool.
  • LV Zhong-liang;YANG Chang-qi;AN Peiwen;TANG Liang
    . 2011, 30(1): 197-203.
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    Multi-Excitation Modal Analysis was used in large structures,such as bridge, construction, aerospace industry. This paper gives a survey of the theory and application in modal parameter identification with Multiple-Excitation, Especially only in response data. Then give a deep discussion on the technique of modal parameter identification with Multi-Excitation in the different assumption of excitation signal model: Stationary Random Excitation and non-stationary random excitation. At last, the development prospect of measurement methods for parameter identification with Multiple-Excitation is summarized.
  • YAN Ke;GE Pei-qi;SU Yan-cai
    . 2011, 30(1): 204-207.
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    Heat transfer enhancement is achieved by flow-induced vibration in elastic tube bundles heat exchangers. To a further study of heat transfer enhancement mechanism and tube structure optimum, it is of importance to study the vibration characteristics of fluid-structure interaction of heat transfer element. Helical tube bundle is a new type elastic heat transfer element. Because of its helical structure, the inside flow of helical tube has a deep influence on its vibration characteristics due to the coriolis force damp. The FEM is used in this paper to study the vibration characteristic of the helical tube with inside flow. The element matrix and tube vibration equation are achieved by the regulation of different spiral angle and coordinate transformation and also the simplification of the connector of the two pipes. The influence of coriolis force damp on the tube vibration characteristics is analyzed. The result shows that the 1st mode frequency decreased acutely because of inside flow of helical pipe. The spiral pipe shows complex mode shape due to the coriolis force damp, and the damping ratio is relative both to the helical pitch winding and the inside flow of the spiral helical tube.
  • YAN Ke;GE Pei-qi;SU Yan-cai
    . 2011, 30(1): 205-207.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Abstract: Heat transfer enhancement is achieved by flow-induced vibration in elastic tube bundles heat exchangers. To a further study of heat transfer enhancement mechanism and tube structure optimum, it is of importance to study the vibration characteristics of fluid-structure interaction of heat transfer element. Helical tube bundle is a new type elastic heat transfer element. Because of its helical structure, the inside flow of helical tube has a deep influence on its vibration characteristics due to the coriolis force damp. The FEM is used in this paper to study the vibration characteristic of the helical tube with inside flow. The element matrix and tube vibration equation are achieved by the regulation of different spiral angle and coordinate transformation and also the simplification of the connector of the two pipes. The influence of coriolis force damp on the tube vibration characteristics is analyzed. The result shows that the 1st mode frequency decreased acutely because of inside flow of helical pipe. The spiral pipe shows complex mode shape due to the coriolis force damp, and the damping ratio is relative both to the helical pitch winding and the inside flow of the spiral helical tube.
  • Huang;Wang WeiMin;Su YiRu;Gao JinJi
    . 2011, 30(1): 208-212.
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    Abstract: This paper presents a strategy to eliminate synchronous vibration of rotor system online. The solution utilizes electromagnetic actuator to generate synchronous rotating electromagnetic force, and the electromagnetic force is applied to rotor synchronous unbalance vibration suppression in the rotor vibration monitoring of the plane. In this research, rotor synchronous vibration and electromagnetic controllable characteristics are analyzed firstly, and then, theoretical analysis on the rotor system is done also. Based on these analyses, an optimal control model was designed, in which rotor vibration response is regarded as control target and the amplitude and phase of coil current are regarded as optimal parameters. And current phase complete period search algorithm was proposed. Simulation is carried out. At last the test equipment is established to be used to experimental study. The experimental results show the proposed algorithm is effective for unbalance synchronous vibration suppression.
  • CHEN Shi-hai;WEI Hai-xia;ZHANG Zi-hua;DU Rong-qiang
    . 2011, 30(1): 213-217.
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    To discuss characteristics of blasting vibration effects of reinforced concrete buildings, a large number of blasting vibration response signals of reinforced concrete building were monitored by locating measuring points on the multi-story reinforced concrete building along the height direction, which was under-drilled through in the course of blasting excavation of a tunnel. Distribution characteristics of spectrum and energy and amplitude variation laws of structural response of reinforced concrete building to the blasting seismic action along the height direction in all direction were studied with the method of wavelet analysis combined with FFT. The results indicate that the frequencies of velocity response signals of reinforced concrete buildings to blasting seismic waves are relatively large and the dominant frequency bands which occupy a large portion of total energy is wide which mainly focus on range of 15Hz~600Hz. The frequencies and amplitudes of velocity response signals of reinforced concrete buildings are individually lower and higher in vertical direction than in horizontal direction, and the ratio shows raising trend with the floor increasing. With the floor changing, characteristics of spectrum and amplitudes of structural response signals to the blasting seismic action in both vertical and horizontal direction change without obeying any laws.
  • LEI Yan-bin;LI Shun-ming;MEN Xiu-hua;SHEN Huan;HAO Qing-qing;LIU Jian-ya
    . 2011, 30(1): 218-222.
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    When the areo-engine is running, the vibration signals measured by the sensors are mixed with all vibration sources and include the very strong noises. It’s difficult to separate the mixed signals with conventional methods of signal processing, which induces the difficulties of the machine health monitoring and fault diagnosis. The principle and method of blind source separation is introduced, and point out that the blind source separation algorithm is invalid in strong noise environment. For the vibration signals in strong noise environment, de-noising the vibration signals with time-delayed auto-correlation method firstly, and then separate the de-noised signals with the blind source separation algorithm. The simulation results verify the effectiveness of the proposed method. Finally, the mixed rotor’s vibration signals is separated successfully using the proposed method, and provides a new approach for the mixed vibration signals in strong noise environment.
  • LI Xudong;ZHANG Lu;MA Yuan;WU Dongliu
    . 2011, 30(1): 223-226.
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    Solutions of dynamic stress intensity factor of several models were obtained accurately, using
    ANSYS commercial FEM software, adopting non-singular elements and the Newmark Integral Method, through
    least square fitting. The method can be used widely for general purpose, which was beneficial and necessary for
    using linear elastic fracture dynamic to solve practical engineering problems.
  • He Songlin;Huang Yan
    . 2011, 30(1): 227-229.
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    In order to improve the accuracy of nonlinear vibration solution obtained by averaging method, the impact of damping on the vibration cycle must be considered.The different function of circular frequency, between the differential equation to be solved and the derived equation ,can be expressed as a polynomial of damping coefficient. Usually it will improve the accuracy of the averaging method in larger scale by take the damping coefficient as the different function easily.The linear damping vibration and Duffing-type damping vibration have been solved with improved averaging method .It is proved that the improved averaging method is effective to improve the accuracy of the solution by compare with the exact solution of the linear damping vibration and the numerical solution of the Duffing-type damping vibration.
  • Jin Haiwei
    . 2011, 30(1): 230-233.
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    Gearbox is a system with complex structure, and the impact of input and output are many factors, so a single-input and single-output transfer characteristics of the system can’t accurately reflect that the actual status of the operation characteristics of the gearbox. In this paper, based on the ARX method of multi-input multi-output modeling, it used the two input signals (the input shaft torque and speed signal) and the three output signals (the output shaft torque, rotational speed signal and the vibration acceleration signal collected from gearbox surface) in this model, and the gearbox model was created as a two-input three-output system. It is shown in the experiment that: ARX model analyze the state of the gearbox from the point of the inherent characteristics of the system, and it can effectively distinguish the different fault states.
  • Lu Chunhong;Bai Hongbai
    . 2011, 30(1): 234-236.
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    By means of the analysis on vibration isolation mechanism of combined positive and negative stiffness, a new type ultra-low passive vibration isolation system was designed in this paper. The method of combined negative stiffness mechanism and positive stiffness spring was used in this isolator so that it possesses high supporting stiffness as well as ultra-low vibration stiffness, and its stiffness also has nonlinear characteristics, which resolved the problem of ultra-low frequency vibration isolation in the traditional passive vibration isolator. By analyzed the mechanical characteristic of this system, the expression of the stiffness of the isolator and the zero stiffness condition of system at the equilibrium position were deduced, which offer theory guide for the design of new type nonlinear ultra-low frequency vibration isolator.
  • Weizhongqing Mabo Douyuan Jiangzhinong
    . 2011, 30(1): 237-241.
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    The fault of gas valve often happen for reciprocating compressor, more than 60% in total number of faults. If the fault is not found and solved in time, the efficiency of reciprocating compressor will be greatly reduced. Viewing of the current reciprocating compressor valve fault diagnosis problems, combining with wavelet de-noising, based on Maximum Likelihood Estimation(MLE)threshold rule feature extracting for weak impact signal of early fault of valve is proposed. The early warning for fault of valve is implemented.