28 January 2018, Volume 37 Issue 4
    

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  • LENG Wu-ming1,2,MEI Hui-hao1,2,NIE Ru-song1,2,LIU Wen-jie1,2,SU-Yu1,2,TANG Sheng-mi1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 1-6.
    Abstract ( 393 ) Download PDF ( 212 )   Knowledge map   Save
    Based on Shuo-Huang heavy haul railway, dynamic response tests are carried out through establishing the simulated loading system of heavy haul train and full-scale model of heavy haul railway subgrade, the dynamic response characteristics of subgrade subjected to cyclic loadings are analyzed. The result indicates that with increasing axle load the dynamic stress peaks at different depths in the subgrade also increase. The larger the axle load, the greater the depth influenced by dynamic stress. There is negative exponential function between dynamic stress peak and depth in subgrade. With increasing axle load the dynamic displacement peaks at the top surface of sleeper nonlinearly increase. When axle load increases to 30t, the subgrade comes to critical failure state. This shows that by construction standard of Shuo-Huang railway subgrade, the maximum allowable axle load is about 27t, if increasing axle load, strengthening measures should be taken to subgrade preliminarily. The testing results have some reference for establishing simulated loading system of moving train and full-scale subgrade model. Meanwhile, the testing results provide better understanding of the influence of train axle load on the response of subgrade.
  • LU Si-liang1 SU Yun-sheng 1 ZHAO Ji-wen 1 HE Qing-bo 2 LIU Fang1 LIU Yong-bin1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 7-12.
    Abstract ( 261 ) Download PDF ( 192 )   Knowledge map   Save
    One-dimensional stochastic resonance (1DSR) methods have been widely used in bearing fault diagnosis. However, some deficiencies still exist in the traditional 1DSR methods such as limited weak signal detection capacity, obvious output noise and inaccurate bearing fault characteristic frequency (FCF) for fault recognition, etc. To address these issues, this study proposes a new two-dimensional complementary stochastic resonance (2DCSR) method to enhance bearing fault diagnosis. First, the acquired bearing fault signal is bandpass-filtered according to the location of resonance band and then demodulated. Then the demodulated signal is split into two sub-signals and the sub-signals are sent to the two input channels of the 2DCSR. The weighted power spectral kurtosis (WPSK) of the output signal is used as the criterion to adaptively guide parameters tuning in the 2DCSR system. Finally the optimal output signal and its spectrum are obtained for bearing fault recognition. Numerical and experimental results show that the bearing FCF can be enhanced by the proposed 2DCSR method, thereby improving the performance of bearing fault diagnosis.
    Key words: bearing fault diagnosis; two-dimensional complementary stochastic resonance; weighted power spectral kurtosis; weak signal detection
  • WANG Shou-cai, GUAN Zhi-dong, LI Zeng-shan, HUANG Xiao
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 13-18.
    Abstract ( 245 ) Download PDF ( )   Knowledge map   Save
    Aircraft will suffer from the impact threat of foreign objects, which cause damages to the fuselage skin. Two domestic aviation company’s maintenance records were investigated from the south and the north, from which we got the damage information and its distribution regularity. Based on the software ABAQUS, a finite element model was developed. Johnson-Cook constitutive mode with no damage was used to study the performance of panels with low-velocity impact. The low-velocity impact test of aluminum plate was designed and implemented to verify the usability of the model. The formula to compute the impact energy from dents depth was obtained, and the damage dents were turned into impact energy. The maximum energy that metal skin aircrafts may encounter was estimated under a certain level. The results show that the depth of the dents is proportional to impact energy when the impact energy is small. At the specified probability level, the maximum impact energy of the wing, fuselage and the whole aircraft is 21.3J, 25.5J, 33.8J, respectively.

  • MENG Qing-li
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 19-27.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In this paper, to solve the problem that the seismic damage of reinforced concrete bridges’ RC piers under strong earthquake is often encountered at home and abroad. On the basis of the results of existing piers/columns seismic strengthening in the domestic and foreign, a new-type RC piers/columns seismic strengthening measures-Precast SFC shell segments wrap the plastic hinge region of RC piers/columns, which is developed. Then, the RC piers in the actual bridge was selected as a prototype, The validity of this RC piers/columns seismic strengthening measures is studied by comparative experimental study of the RC piers and the strengthened RC piers in the pseudo static tests, the experimental results showed the RC/columns pier seismic strengthening measures can enhance the bearing capacity and energy dissipation capacity of RC piers without changing their plastic hinge position. In additional, the nonlinear seismic time history response of the experimental RC piers reinforcement was analyzed and compared under the typical ground motion in different site conditions, which further verified the effectiveness of the new-type seismic strengthening measures.
  • Zeng Chao,Tang Baoping,Deng Lei,Xiao Xin
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 28-34.
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    Aiming at the problems of machine vibration wireless sensor networks node with narrow bandwidth has low network transmission rate and poor real-time capability, especially in mass raw data transmission requirements, a Multi-channel Data Transmission method based on tree-star Hybrid Topology (MDTHT_WJ) is proposed. Firstly, to avoid adjacent channel interference affect parallel communication, allocate channels for each wireless sensor network node with minimizing inter-tree communication interference, each node forms a tree-star hybrid topology network with allocated channel for data transmission after synchronous data acquisition. Then, handshake mechanism and preemptive priority mechanism is utilized to solve network partitions problem. Finally, the network short address of each data acquisition node is regarded as scheduling information, routers broadcast the scheduling information with beacons, and each data acquisition node decides to whether transmit data or sleep according to the scheduling information, realizing the time-scheduled inner-tree communication with minimizing power consumption. Comparative experiment with carrier sense multiple access with collision avoidance is carried out and experiment results indicate that the network transmission rate of machine vibration wireless sensor networks can be improved effectively by this method.
     
  • LIU Geng,NAN Mi-mi,LIU Lan,WU Li-yan,ZHAO Ying
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 35-41.
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    Aiming at the vibration and noise in gear systems caused by gear tooth friction, this paper summarizes the relative articles in the past two decades. This review includes the tribodynamics models, dynamic responses, gear friction noise and their experiments. The methods to analyze the tribodynamics and the friction noise of gears are summarized and some conclusions are drawn from the present studies. Based on the summary of the existing researches, some suggestions are presented for the future research and development.

  • Hao Long1, Yang Jin-fu1, Han Dong-jiang1, Tang Chang-liang1, Zhang Yan-ming2, Ou Rong-xu2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 42-48.
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    A 10 kg flexible rotor supported by gas bearings test rig was established to conduct the dynamic characteristics experiments with different damping coefficients of “O” rings. The dynamic characteristics of rotor bearing system with acrylonitrile-butadiene “O” rings, fluorine rubber “O” rings, and silicon rubber “O” rings were researched based on the test rig at the same bearing supply pressure, respectively. Translational critical speed, cone dynamic critical speed and the first bending critical speed were below the maximum operating speed of rotor. Vibration amplitudes of the first two critical speeds were similar. The amplitude of working frequency was large and the rotating speed increasing rate decreased at the first bending critical speed. With acrylonitrile-butadiene “O” rings and fluorine rubber “O” rings, the gas film oscillation occurred when the rotating speed was larger than the first bending critical speed and the amplitude increased. It can be concluded from experiments that the dynamic stability of first bending critical speed improved with increasing of O-ring damping. But the low frequency oscillation is more easily to occur and the vibration amplitude increases after the gas whip with larger damping O rings, this is dangerous to the safety of the system.

     
  • HAN Qingzhen 1 HE Ren 1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 49-54.
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    The dynamic behaviors of nonlinear relative rotation system with nonlinear stiffness is studied. The torque perturbation is made as control parameter, and the equilibrium’s stability of the torsional vibration system is judged by the Routh-Hurwitz criterion. The bifurcation theory is used to analysis the bifurcation behaviors of the equilibrium, and the condition of Fold bifurcation of the equilibrium is derived. The bifurcation set of the equilibrium on the parameter plane is obtained by simulation, and the stability of equilibrium in different parameter regions are studied. The global dynamic behaviors of torsional vibration system are studied by the bifurcation map and period three motion and chaotic motion are obtained. Symmetric and asymmetric fold/fold burstings are obtained by adjusting the quadratic nonlinear stiffness coefficient.

  • YU Xian-feng1,2 XIE Zhuang-ning2 LIU Hai-ming1 ZHANG Cheng3 WANG Xu1 DONG Rui1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 55-59.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The effect of gas resonance on wind tunnel experiment for internal pressure in a building, especially in a two-compartment or multi-compartment building, with a dominant opening cannot be omitted. Similarity and additional internal volume requirements for internal pressure experiment are firstly described. The building internal cavity volume used at model-scale should be distorted by a factor equaling the square of the ratio of the full-scale to model-scale velocities, and the additional internal volume must be a deep and narrow cavity. Then, the gas natural frequency equation is introduced from reciprocating compressor piping system into wind tunnel studies on internal pressure. Finally, wind tunnel experiments on internal pressure for a two-compartment building with two kinds of additional distorted volumes are carried out. Results show that the measured internal pressure response will be inaccurate because of the influence of gas resonance when the additional distorted volumes are much deeper and narrower.
     
  • CAI Yaoquan1,ZENG Fanming1,LIU Jinlin1,Liu Shuyong1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 60-66.
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    Propeller-shaft systems and hull stern coupling vibration is the most important factor for hull vibration and noise reduction. To find out the basic excitation mechanism has important significance to the recognition and efficient control of vibration and noise. According to the operating state of shafting, the factors such as operating conditions, alignment state, and exciting force which have an effect on shafting-base-hull coupling vibration are based on FEM rotor dynamic theory to analysis. Under the straight alignment, the oil and water film 8-dynamic coefficients are calculated by Reynolds equation for four shafting operating states, the stiffness and damping matrices of single multipoint support bearing are established, the FEM of shafting-base-hull is established. Based on this, alignment state effect on shafting-base-hull coupling vibration is analyzed by FEM power flow, according the result of system dynamic response. The result shows that different operating states can induce different internal stress, different bending deformation and then the change of bearing characteristic. With the corresponding, the power flow passed hull can change which induce system coupling vibration and cause different noise.
  • DOU Zuozheng1, LI Yinong1, DU Minggang2, YANG Yang2, ZHAO Layue2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 67-74.
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    To prevent torsional resonance of multi-gears of multi-speed planetary transmission system which because of improper choose of the parameters, dynamic optimization and modification for the parameters of the system was conducted by using the multi-step genetic algorithm which adopt relative sensitivity of natural frequencies to parameters of the system to be the constraint conditions, and to minimize the change rate of parameters relative to its initial value was taken as the dynamic objective function and dynamic constraint boundary. Comparative study of taking the change rate of parameters relative to its initial value to be optimal and taking every step to be optimal when different step size was taken into consideration had been done. And the characteristic of natural frequencies to parameters of planetary transmission system apply to multi-gears and single-gear was analyzed. The result indicate that better optimization result can be got in the multi-step genetic algorithm when using the change rate of parameters relative to its initial value to be optimal compare with using every step to be optimal; The natural frequencies to parameters of single-gear of planetary transmission system can not be used for guidance of multi-gears system directly. Resonance will not produce at the range of working speed of the system after optimization and modification of parameters, and a guidance for the design of the planetary transmission can be provided by this paper.

  • Zhang Rui1, Deng Aidong1,Si Xiaodong2, Liu Dongying1, Li Jing,3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 75-81.
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    Acoustic emission signals are highly susceptible to noise interference in rotating machinery fault diagnosis. The empirical mode decomposition (EMD) associates with mode mixing, this paper achieved a method that de-noising and the fault diagnosis of the rotating machinery AE signal based on empirical wavelet transform. This method takes the advantages of the EMD and wavelet transform, classifying the Fourier spectrum by its adaptive property, constructing the wavelet filter bank to extract the different intrinsic mode components of acoustic emission signal, which can eliminate the mode mixing phenomenon. Then the Hilbert transform was carried on the component of the acoustic emission signal so as to realize the de-noising and fault diagnosis. Adopting this method to de-noising the simulations signal that has been added noise, at the same condition, compared with the result of global threshold value de-noising, default threshold value de-noising, tackle high frequency coefficient de-noising based on dB4 and EMD de-noising. Applying this method in the practical AE rubbing signal. Results showed that: Intrinsic modes of the signal can be decomposed effectively through EWT method, the decomposed mode is less and there is no mode that is difficult to explain. Furthermore, de-noising effect is superior to other methods and has great advantage in AE signal fault diagnosis.
     
     
  • Xiang Yiqiang1,Lin Heng1,Chen Zhengyang1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 82-87.
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    Submerged floating tunnel is a novel sea-crossing structure suspended under the water. In order to analyze the dynamic response of the submerged floating tunnel subjected to moving load, a submerged floating tunnel is simplified as a spaced beam on elastic supports. Considering the fluid inertia effect and damping effect by Morison equation, it is proposed that the dynamic differential governing equations of the submerged floating tunnel subjected to moving load through modal superposition and Galerkin methods. Meanwhile, the numerical examples are mentioned to solve dynamic differential equations by using the fourth-order Runge-Kutta method. The results show that the impact coefficient and acceleration response of structure are related to the fluid effect. Furthermore, the fluid effect is affected by the length of structure and mode number. Besides, the tether stiffness is disincentive to the impact coefficient and acceleration response. Moreover, high speed moving load will result in the structure more dramatic fluctuation.

     
  • LI Fang-shuo,CHEN Qian,ZHOU Jun-hui
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 88-93.
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    The dynamic property of dual-chamber solid and liquid mixture vibration isolator can be easily adjusted by changing the section area of the oil tube which connects the two chambers. An active group valve containing four branches was designed to control the flow of oil flowing between the two chambers. Dynamic experiments for the novel isolator with different apertures were performed to verify the efficiency of the active group valve. The experimental result turned out that the stiffness and damping properties of the novel isolator could be effectively adjusted by actively control the group valve. Then, the FEBC strategy combing with various methods of identifying the base frequency of the vibrating signals were introduced. At last the semi-active control of the target isolator based on FEBC strategy was carried out experimentally. The test result showed that the semi-active system with stiffness-varying property did well in avoiding the resonance response and improving the isolation performance.
     
  • XIA Zhao-wang1, Mao Kai-jie1,Wang Xue-tao1, Jiang Wen-an2,YANG Shao-pu3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 93-98.
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    The traditional viscoelastic damping will be failure, when truss structure of offshore platform exposed to high-energy ultraviolet light and salt spray for along period of time. The semi-active particle damper may be applied in extreme temperature environments where most conventional dampers would fail. In addition, it can meet the needs of the complex external load. The application of semi-active particle damping will be studied in vibration reduction of truss structure of offshore platform. A coupling simulation algorithm based on the discrete element method and finite element method is used to calculate the semi-active particle damper in the truss structure of offshore platform. The influence of control strategy, control current and particle parameters on the vibration characteristics of truss structure of offshore platform is analyzed. The research results show that the
    damping effect of semi-active particle damper is better than that of passive particle damper, and reasonable correlation is demonstrated between simulation and test.

  • ZHUANG Peng1, 2, 3, WANG Wenting1, HAN Miao1, 2, 3,XUE Suduo4
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 99-109.
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    A new type of hybrid energy dissipation device termed as friction-shape memory alloy (SMA) spring device (FSD) is presented in this investigation. This hybrid device consists of friction component and large-scale superelastic SMA helical springs. Based on the mechanical models of SMA spring and frictional force model, a restoring force model for the FSD is developed. The proposed FSD devices are used as energy dissipation brace (Friction-SMA spring Brace, FSB) for seismic control of a single-layer spherical lattice shell with surrounding columns. By using the ABAQUS software, the FE model of the complete structure is established and the dynamic elasto-plastic analysis under multi-dimensional seismic excitations is carried out. The displacement response, acceleration response, equivalent plastic strain and energy response of the roof and the supporting structure in the controlled and uncontrolled lattice shells are compared and analyzed. The results indicate that the FSB devices in the substructure of the lattice shell roof provide full hysteresis loops that benefit for energy dissipation. Under strong earthquakes, the energy dissipation of the controlled structure mainly depends on the SFB, which reduces plastic development and seismic damage. In addition, the FSB devices exhibit superior seismic control effect of the horizontal response to that of the vertical response of the lattice shell roof and its supporting structure.
     
  • YUPei-xun 1 PAN Kai 1 BAI Jun-qiang 2 HAN Xiao 2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 110-115.
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    Coupled with turbulent velocity generation model and sound propagation equation, the SNGR (Stochastic Noise Generation and Radiation) method which is able to simulation the noise source propagate in the non-uniform flow field has been formed. In order to validate the SNGR method, the noise propagation of the 30P30N model’s slat is selected. Comparing the frequency spectrum of the monitor at trailing edge of slat and the contour of noise directivity, numerical results are well consistent with the literature’s results. Several different geometrical configurations of slats are designed, researching their depressing effects on aerodynamic noise. Adopting the SNGR method, the acoustic pressure contour and noise directivity contour of each configuration are analyzed, and the noise depressing effects are validated by means of LES/FWH method, the result shows: 1. By extending the effective length of the leading edge of slat, the stability of shear layer is strengthened and the intensity of the collision between shear layer and leeward region of slat is decreased. Because of these reasons, the noise of slat is reduced. 2. The SNGR method can be applied to the noise prediction and suppression of two dimensional high-lift configuration.
     
  • ZHANG Da-peng, LEI Yong-jun, SHEN Zhi-bin
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 116-122.
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    The dynamic model was established and vibration responses were examined for a nonuniform nanobeam, which was resting on a viscoelastic foundation and subjected to a magnetic field. Based on nonlocal Euler-Bernoulli beam theory, Kelvin viscoelastic foundation model and Maxwell relation, the governing equations of the system were derived. The natural frequencies of the nonuniform nanobeams were then obtained by solving the governing equations via transfer function method incorporating with perturbation method. Subsequently, the influences of nonlocal parameter, the strength of the magnetic field, relaxation time and taper parameter on the damped frequencies and damping ratios were examined. The results show that the proposed model is available for dynamics analysis of a nonuniform nanobeam resting on a viscoelastic foundation in a magnetic field.
     
  • YANG Renshu1,2,CHEN Jun1, XIAO Chenglong1,CHEN Shuaizhi1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 123-127.
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    The dynamic failure mechanism of rock in intermediate and low strain-rate is analyzed from three aspects --- failure modes, energy absorption and mechanical parameters, A new method to calculate the dynamic compressive strength of rock is presented. Pseudo-static method combined with principle of virtual work is used to build the formula, as we consider that the work done by external force to rock is more than the internal energy loss, and the damage happened because of the rock cannot endure the external load. Therefore the dynamic compressive strength σcd is equal to the static compressive strength σc’ plus the increased strength which is caused by strain-rate effect. Then the calculated value of dynamic compressive strength is compared with the experimental results in other literatures, which the two values are similar.

  • ZHAO Zhe 1 JIA Yuhong 2 TIAN Jianbo3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 128-135.
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    It is required that, during low-velocity taxi phase, neither nose gear nor main gears shall side slide when aircraft swerving[1]. In practical application, nose wheel turns at a constant rate, which equal to the lower limit of nose wheel allowable steering rate, to meet above requirements [1]. However, in this control method, aircraft’s ground maneuver control performance reduces, significantly. Meanwhile, due to the degree of freedom of a multiple-bogie undercarriage system is high, it is too complicated to find the general solution of nose wheel allowable steering rate. To solve above problems, set up a kinetic analysis model of a multiple-bogie undercarriage system and design a control law based on the fuzzy control theory. The calculations and simulations demonstrate that allowable nose wheel steering rate could be affected by aircraft’s velocity, nose wheel steering angle and engine thrust; allowable nose wheel steering rate could be improved by reducing aircraft’s velocity and engine thrust on condition that aircraft’s configuration is identical and aircraft’s safety and performance not reduce; Fuzzy control theory could be implemented on nose wheel steering rate control design; Nose wheel steering rate control law based on the fuzzy control theory could fully develops aircraft’s ground maneuver control capability and improves aircraft’s ground maneuver control performance.

     
  • Zhang Yanxia1,2, Huang Weizhen1, Liu Anran1,Liu Xuechun3, Li Rui1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 136-146.
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    A new kind of self-centering and free-repair brace with friction damper is put forward in the paper, which the self-centering and the energy dissipating capacity are provided by the prestressed steel strand and the friction dampers respectively.In this thesis, the specimensare scaledto 0.6, as well as low cyclic loading tests with two designed friction conditions have been conducted to investigate the deformation performance, hysteretic characteristics, energy-dissipatedcapacity,plastic development,post-tensioned forcevariation and self-centering capacity. Simultaneously, numerical simulation towards the testing process has been carried out by adopting software ABAQUS, which results have been compared with that from the test. The researching results indicate that the new-typebrace can be installed feasibly and fleetly, as well as possessing favorable energy dissipating and self-centering capacity. All parts of the brace can maintain elastic during the loading process, the residual deformation is very small in later period of the loading process, stiffness of the brace remains relatively large. The installation of the brass sheets in friction dampers can avoid the maturing condition of friction interfaces as well asproviding stable energy friction capacity. Reduction of the cable forces in braces is very small after the loading process. Therefore, the braces can continue to work, achieving the design target of “self-centering and free-repair”, as well as reducing the repairing cost of the architecture.
  • LI Shu-xun1,2, WANG Tian-long1,2,XU Xiao-gang1,2, MENG Ling-qi1,2, LOU Yan-peng1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 147-152.
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    Aiming at the problem of strong fluid vibration induced by improper design and selection of throttling element, high pressure drop multistage sleeve trap was taken as research object. Based on the theory of direct boundary element method, flow-induced vibration of traps of different pressure-drop stages and throttle hole diameter was simulated by numerical method. Thus, the vibration spectrum curves and total vibration level curves of Monitoring point at different openings were obtained. The results showed that flow-induced vibration spectrum characteristic is mainly affected by interval throttling elements but less affected by opening degree; Under constant rated flow and pressure, total vibration level reduces with the increase of pressure-drop stages, while the characteristics of vibration spectrum remains unchanged; With the decrease of throttle hole diameter, the total vibration level significantly reduces, and main ingredients of vibration concentrate in 50~500 Hz, which provide references for design and selection of throttling element. Considering the processing characteristics of the throttle sleeve, the throttle hole diameter should be 4~5 mm. In practical use, steam traps should better work under the middle opening degree in order to reduce vibration.
     
  • LIU Nian-nian1, SONG Dan-dan1, JIN Hui2, ZHANG A-man1,
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 153-159.
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    For the established scaling-shrank model of composite armor, based on the algorithm of multiple substance fluid-solid coupling, the damage process of the hemispherical shaped charge acting on the composite armor structure is simulated by using AUTODYN software and the numerical results match the experimental ones well. Besides, the damage characteristics of shaped charge to the pressure-resistant and pressure-nonresistant shell are investigated as well as its destructive form to the after-effect armor, so as to serve as a reference to the damage assessment of the underwater weapons with shaped charge acting on the double-shell submarine and to the anti-shock research and design of the warships.

  • TA Na1, ZHANG Jing1, XU Lifu1, ZHOU Lei2, HUANG Xinsheng2, RAO Zhushi1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 160-164.
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    To explore the dynamic characteristics of basilar membrane, the dynamic responses to pure tone in the basilar membrane (BM) of guinea pig were measured by using Laser Doppler Vibrometer (LDV).14 fresh specimens of guinea pig cochlea in vitro were used to test the velocity response and the displacement response of BM under pure tone excitation of 70dB, 80dB, and 90dB SPL.And the vibration characteristics of BM was analyzed by changing the frequency of the input sound signal.The experimental results show that the vibration of BM under pure tone excitation is sinusoidal vibration. The vibration velocity and displacement of BM at the same location varies from the frequency of input sound signal and the BM has the frequency selective characteristics and the maximum vibration response appears at the best frequency.The phase responses of BM under different sound pressures excitation have the similar trend and phase-delay increases rapidly above the best frequency. The sound transmission in the BM has the characteristic of travelling wave. The experimental methods and results guided studying the auditory mechanism of human ear.
     
  • Cheng Junsheng2,Liu Zhentao, Yang Yu
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 165-169.
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    of a parameter of controlling a component’s bandwidth must be determined artificially When using adaptive and sparsest time-frequency analysis (ASTFA) .A improper will lead to the problem of mode mixing.Complete adaptive and sparsest time-frequency analysis( CASTFA) was proposed to restrain such a drawback of ASTFA.CASTFA use the intrinsic mode function(IMF) generated by ensembleempirical mode decomposition (EEMD) as reference to adaptively determine the .the simulation example showed the CASTFA can restraining the mode mixing of ASTFA,and perform better than EEMD in restraining mode mixing.The practical rotor rubbing fault diagnosis result turned out that CASTFA is efficient.

  • DU Chunyang YU Dianlong WEN Jihong LIU Jiangwei JIA Pengfei
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 170-176.
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    In order to control the vibration of the pipe, the vibration propertiesof periodic beamwith functionally graded material(FGM)are investigated. Based on finite element method, the band gap of periodic pipeline with functionally graded materials was calculated.The properties oftunable band gap of FGM are discussed in detail, such as the length of pipe with functionally graded materials in cell unit, properties of transition function. Results show that a considerable stress concentration can be alleviated by the application of this FGM. The results reveal that the band gap of classic periodic pipeline can be improved as well as the stress concentration problem because of the functionally graded materials.The FGMs can be used to provide a new way for tunableband gap and eliminating the stress concentration.
     
  • ZHAO Dezun1 LI Jianyong1.2 CHENG Weidong1 WEN Weigang1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 177-183.
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    Due to the variable rotational speed, it is more difficult to extract multi-fault features of rolling element bearing, which may tightly couple together and interfere with each other. As such, a new multi-fault feature extraction method based on the iterative generalized demodulation algorithm is proposed. We utilize the time-frequency characteristics of the compound faults bearing signal and the merits of the generalized demodulation algorithm which can transform an interested curved time-frequency component of the non-stationary signal into linear path paralleling to the time axis to directly extract the multi-fault features. The proposed method can be summarized as four parts: obtain the equation of rotational frequency curve by rotational speed pulse signal, the phase functions and phase points are calculated based on the fault characteristic coefficient and the rotational frequency equation; calculate the envelope signal by the Hilbert transform; demodulate the envelope signal by the iterative generalized demodulation algorithm; obtain the frequency spectrum of demodulated signal to detect fault feature. The studies of simulated and experimental multi-fault bearing signals validate that the proposed method is reliable to diagnose multi-fault bearing under time-varying rotational speed.

  • HE Tao 1, 2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 184-190.
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    This paper presents a concise review of numerical solution techniques for fluid-structure interaction (FSI) problems. Various coupling algorithms, as well as their applications, are briefly described. The main focus is placed on those classic references and most recent artworks. Prospective trend of FSI solution methods are predicted while some unresolved issues are summarized at the end of this work.
  • CHEN Qiang1, ZHANG Peng1, LI Yan-bin1, WU Shao-qing1, 2, FEI Qing-guo1, 2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 191-196.
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    With the combination of the finite element method (FEM) and the power injection method (PIM) considering thermal effect, a simply-supported L-shaped folded plate is taken as object of research in order to study the influence of aspect ratio on the statistical energy analysis parameters under normal and thermal environments. Firstly, numerical analysis under rain on the roof excitation is studied to verify the accuracy of the proposed method. Then, the effect of aspect ratio on the modal density, the internal loss factor and the coupling loss factor under normal and thermal environments is studied. Results show that the aspect ratio of plate has minor effect on the internal loss factor and the coupling loss factor of the structure under normal environment. Under thermal environment, the coupling loss factor is firstly increase and then decrease with the increasing of the aspect ratio of plate. However, the increase of the aspect ratio of plate has little effect on the internal losing factor. The modal density increases with the aspect ratio of plate in both normal and thermal environments.

  • Xiong Zhongming1, Wei Jun1,2, Guo Yalei1, Wang Bingrui1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 197-202.
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    The activity of ground fissures in Xi'an weakens gradually and tends to be stable. Taking the ground fissure f4 in Tangyan Road as the research object, the finite element type selection of the spanning ground crack structure was carried out. Various parameters of refined model in the structure across ground fissure were analyzed quantitatively by using ABAQUS software. Then, the 3D solid refined models of frame structure in common site and ground fissure site were established, which considered the position and quantity of rebar, and the calculated results were compared with the results of shaking table test for ground fissure. Based on the quantitative analysis of the displacement and displacement angle of the frame, the influence of the ground fissure on the frame structure under excitation of the non-uniform seismic is obtained. Calculation results show that the existence of ground fissure aggravated the damage of the superstructure during earthquake, and the seismic response of the structure is related to the type of earthquake, the intensity of the earthquake and the location of the floor. In addition , along with the increase of seismic intensity, the dynamic response of the ground fissure increased significantly.

  • ZHENG Hongbo1 Hu Fang2 HUANG Zhiwei3 ZHANG Zhiyi1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 203-207.
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    The thrust bearing pedestal in a propulsion shafting is the main path for longitudinal vibration to transmit from the propeller to the hull. A propeller-shaft-thrust bearing pedestal vibration model is established to study the active longitudinal vibration control, and the four-pole parameters method is adopted to derive the frequency response functions of the disturbance and control channels, and the analysis of active control effect is done through numerical simulation. The simulation results has shown that the adaptive control strategy can reduce longitudinal vibration of the thrust bearing pedestal effectively when the longitudinal control force is exerted on the thrust bearing pedestal. To verify the control method, with research object of shafting system, actuators are mounted on the thrust bearing housing symmetrically, and response to the controller to cancel the effects of the disturbance. Experimental results demonstrate that the control method can suppress the longitudinal vibration of the thrust bearing pedestal effectively, and the peak of power spectrum decreases by about 90% within the 100Hz.
     
  • Yan Guiyun1,Fang Yiwen1,Wu Yingxiong2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 208-218.
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    Far-field long-period ground motions were featured by long duration and rich low frequency components. Particularly, multiple cycle pulses similar to harmonic vibration were generated at the late stage of some seismic waves. These may cause the adverse influence on the seismic performance of the long-period structures including the isolation building, which needed to be investigated deeply. To this end, the characteristics of far-field long-period ground motions were discussed. Then, six far-field long-period earthquake records and three common earthquake records were selected as the input of ground motions, and the seismic responses of a RC mid-story isolated frame structures were obtained by nonlinear analysis. Also, the impact of the long-period components of seismic waves, especially harmonic-like components on shock absorption performance were investigated. Further, a combined isolation scheme by the addition of viscous dampers in the isolation layer was proposed, and its effects on limiting deformation of the isolation layer and reducing nonlinear responses were explored. The results show that the effectiveness of the mid-story isolation subjected to far-field long-period ground motions on reducing nonlinear seismic responses are not as good as those subjected to common ground motions. Particularly, the nonlinear responses of the mid-story isolated structure are seldom reduced or significantly enlarged under the far-field harmonic-like strong ground motions when compared with those of the seismic structure, and the maximum displacement of isolation bearings is far beyond the allowable displacement. It is also indicated that the combined isolation can effectively control nonlinear responses of the mid-story isolated structure under far-field long-period ground motions, especially harmonic-like ground motions. In particular, the maximum displacement of the isolation bearings can be significantly decreased, preventing the destruction of the isolation bearing.
  • Shao Yuan1.2 Sun Zong-guang1 Chen Yi-fei1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 219-225.
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    According to condition of the short suspenders in half-through arch bridge structure are easier to be ruined firstly, the stiffness difference of each suspender departments is analyzed. Taking a half-through concrete-filled-steel-tube arch bridge as the object of study, the elastic modulus of suspender element is adjusted to make the equal stiffness design. The stress response curve of suspenders is obtained and the impact coefficient is calculated under the vehicle load with vehicle-bridge coupling method. Compared with the initial model, dynamic response of arch bridge suspenders is analyzed. The results show that the stress of short span is apparent decline in equal stiffness model and the stress difference of each suspender is reduce; the suspender impact coefficient is reduce and the difference between short and long suspender is reduced as high as 50%; the amplification of roughness level on impact coefficient does not change with stiffness adjustment. It is shown that equal stiffness design for arch bridge suspenders can effectively balance the suspender stress, and make the impact effect more uniform. The durability of suspenders is enhanced to provide the basis for practical engineering application.
     
  • WANG Zong-lian, REN Hui-lan, NING Jian-guo
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 226-232.
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    To improve the acoustic emission (AE) localization accuracy in anisotropic material, the time for sensors receiving the acoustic emission signals is determined from the signals de-noised by wavelet transform based on optimum wavelet base through using threshold method. Lead-off tests were implemented on steel and wood plates to simulate the acoustic emission sources. The acoustic emission sources locations were calculated based on Geiger algorithm before and after signals de-noising, and the localization results showed that the localization method based on wavelet transform de-noising could improve the acoustic emission source localization accuracy in anisotropic material effectively. Acoustic emission sources localization in alumina ceramic specimens during compression failure was employed using the new acoustic emission localization method and the localization results reflected the dynamic fracture process within the material effectively.
     
  • ZHU Qiankun1,2,CHEN Kai1,DU Yongfeng1,Li Hongnan1,LIU Lulu3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 233-239.
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    In order to study the dynamic response of long-span flexible stair under human-induced excitation when considering the interaction of human-stair structure, so a single degree of freedom dynamic response mathematical model was defined, and obtained the acceleration frequency response function. human-stair interaction system was defined based on pedestrian on stair. Biomechanical model up and down stair were built by testing data. The model is equivalent to the three element nonlinear equations with parameters and massive vertical acceleration of pedestrian walking on stair were obtained. FFT was used to get the input parameters, the output parameters mass, stiffness, damping, were obtained by solving the equivalent equation set by least square method. The distribution of the three parameters were analyzed. The formula of the three parameters were built by the quadratic surface fitting. Finally, the pedestrian up and down stairs biodynamic model was built.
     
  • ZHAO Dongfu1,2,3, GAO Haijing1,2,JIA Penghe1,2,WEN Hao4,YANG Jianhui4
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 240-248.
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    Experimental study was conductedonthe performance deterioration of high strength concrete (HSC, C60) subjected to different heating temperature and time,and comprehensive means of scanning electron microscopy, mercury pressure measurement, ultrasonic detect and Micro hardness tester were used to investigate the microstructure changes of HSC. The changes of color of the specimen, compressive strength, elastic modulus, mass loss, burst mechanism and microstructure of HSCwere analyzed. The results show that the color of HSC is shallow after different high temperature history, and it would be rusty red from one hour of 300℃ to two hours of 300℃, the appearance could be grayish white at 700℃ to 900℃. Moreover, HSC would burst at 500℃, and the cracking temperature is much lower than ordinary concrete. The root causes of the deterioration of macro-mechanical properties are gel molecules, cement hydrates and other thermal decomposition, so that the surface and internal cracks and micro-cracks, high-strength concrete microstructure gradually deteriorated. With the rise of heating temperature and time, the compressive strength, elastic modulus andmass loss of HSC decrease gradually. On this basis, the change of heating temperature is related to the performance degradation of HSC has a greater impact.

     
  • Zhang Shaohui Luo Jiesi
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 249-256.
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    Build fault diagnosis model based on deep learning by time domain or frequency domain as a low-level input information directly can effectively weaken the interference of man-made factors and improve the development of artificial intelligence in mechanical fault diagnosis. However, time domain signal length is difficult to draw, while frequency domain signalis too length lossing computation efficiency. Aiming at the problem, put forward to extract frequency domain signal envelope, which would get the trend of frequency information, then combined with sparse autoencoder to constructs the fault diagnosis mode. Gearbox fault diagnosis experiments indicate that, comparing with the original input frequency domain, the proposed method can effectively speed up the computation process and decrease the memory space, while keeping the ability of condition recognition.
  • QIN Bin YI Huai-yang WANG Xin
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(4): 257-262.
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    In view of load variety, nonlinear and strong coupling of the wind turbine system, and complex mechanism and large amount of computation of traditional blade root load models, a neural network model based on extreme learning machine (ELM) was proposed to predict the blade root loads in this paper. Firstly, the factors that affect the blade root loads were analyzed, and the model inputs were determined by the principal component analysis. The data from National Renewable Energy Laboratory (NREL) was then used to set up training and test sets, and the blade root loads of a 5MW wind turbine system were modelled and predicted by the proposed method. Finally, the model performance was compared with that of the model established based on the support vector machine (SVM). The simulation results show that the ELM model has high training speed and high prediction accuracy, which verified its feasibility and effectiveness.