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18 August 2017, Volume 37 Issue 4 Previous Issue    Next Issue

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Relationship Between Karhunen-Loève Transformation and Modal Decomposition Under Ambient Excitations 2017, 37(4): 1-4.  DOI: 10.3969/j.issn.1006-1355.2017.04.001 Abstract ( )   PDF (1302KB) ( )   As the best transformation based on the correlation function, Karhunen-Loève transformation (KLT) has been paid wide attention in vibration analysis. However, the method lacks a clear and complete modal interpretation. In the perspective of spatial geometry, modal decomposition in vibration analysis is a procedure of expanding response signal on the bases of modal shapes, while KLT is a projection procedure of the signal in the space composed by orthogonal KL eigenvectors. This paper discusses the relationship between KLT and the modal decomposition under ambient excitation. The results show that the KL eigenvectors are convergent to the weighted modal shapes, the KL eigenvalues represent the energy contribution of the corresponding modes, and the KL coefficients converge to the modal coordinate. Finally, the analytical conclusion is verified by numerical simulation. Related Articles | Metrics

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Vibration Characteristics of a High-damping Propeller Subjected to Broadband Excitation Forces yong chen 2017, 37(4): 5-10.  DOI: 10.3969/j.issn.1006-1355.2017.04.002 Abstract ( )   PDF (1635KB) ( )   A new structural form of high-damping propeller was raised in this paper. The random vibration characteristics of both new-form propeller and traditional one were researched respectively and compared by simplifying them into beams. Based on the statistical characteristics of isotropic turbulence, the pressure spectrum acted on the propeller surface was computed firstly using correlation method; then the influence of system parameters on the power spectral density of blades’ velocity response and the unsteady force transmitted to the hull were discussed by random vibration theory based on modal superposition method, this research showed that the new structural form of propeller can reduce the blades’ peak response in natural frequencies. Related Articles | Metrics

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Optimal Control of a Suspension System with Input Time-delay 2017, 37(4): 11-14.  DOI: 10.3969/j.issn.1006-1355.2017.04.003 Abstract ( )   PDF (1291KB) ( )   With the application of active control suspension system, inevitably there will be delay factors in the automobile suspension system. Based on the time-delay 2DOF active suspension system as the research object, traditional control law without considering the lag and the optimal control law through state transformation and system discretization method are respectively apllied on the syestem .the control system response and stability characteristics are compared. When the traditional control law was applied on the system, theoretical analysis and numerical simulation show that: when the delay value is small, the system remains stable, But if it reaches a certain value, the system response characteristics may change qualititively, even become divergent and instable. The state transition method is used to deal with the time lag for active control system, which can guarantee the stability of the system. The control law can reflect the influence of input delay on the control equations effectively. Related Articles | Metrics

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Vibration Model Updating of Auxiliary Converter Cabinets Based on Load Identification 2017, 37(4): 15-19.  DOI: 10.3969/j.issn.1006-1355.2017.04.004 Abstract ( )   PDF (1546KB) ( )   In order to improve the accuracy of the vibration response simulation results for a metro vehicle’s auxiliary converter cabinet, a method of vibration model updating combined load identification with optimization is proposed. Firstly, the transfer function between excitation and vibration response is calculated in the finite element model of auxiliary converter cabinet, and the excitation spectrum applied on the measuring points of auxiliary converter cabinet is calculated by using the transfer function and the test data. Secondly, sequence quadratic programming is adopted to carry out the model updating for finite element model. The multi output model updating problem can be transferred into single output model updating problem by constructing a proper objective function. Finally, the modified finite element model is analyzed and the vibration response results between numerical simulation and test are compared to verify the correctness of proposed model updating method. The method can further reduce the vibration and noise of auxiliary converter cabinet to create the necessary conditions. Related Articles | Metrics

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Optimization of Weighting Factors for LQG Controller of Active Suspensions Based on FOA Algorithm 2017, 37(4): 20-24.  DOI: 10.3969/j.issn.1006-1355.2017.04.005 Abstract ( )   PDF (1564KB) ( )   Related Articles | Metrics

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Comparative Study on the Vibration Isolation Performance between the Entirety Double-layer and Distributed Double-layer Vibration Isolation Systems 2017, 37(4): 25-29.  DOI: 10.3969/j.issn.1006-1355.2017.04.006 Abstract ( )   PDF (1346KB) ( )   Related Articles | Metrics

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Natural Frequency Analysis of a Wind Turbine Tower 2017, 37(4): 30-33.  DOI: 10.3969/j.issn.1006-1355.2017.04.007 Abstract ( )   PDF (1286KB) ( )   Related Articles | Metrics

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Analysis of Acoustic Performance of Honeycomb Sandwich Panels Based on Virtual. Lab Acoustics 2017, 37(4): 34-39.  DOI: 10.3969/j.issn.1006-1355.2017.04.008 Abstract ( )   PDF (2435KB) ( )   Related Articles | Metrics

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Vibrational Power Flow Analysis of the Functionally Graded Beam with an Open Crack 2017, 37(4): 40-46.  DOI: 10.3969/j.issn.1006-1355.2017.04.009 Abstract ( )   PDF (1705KB) ( )   Related Articles | Metrics

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Test and Simulation of Double Layer Vibration Isolation Based on dSPACE 2017, 37(4): 47-51.  DOI: 10.3969/j.issn.1006-1355.2017.04.010 Abstract ( )   PDF (1687KB) ( )   Related Articles | Metrics

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Application of Modified ARMA Model in System Identification for Micro-cantilevers 2017, 37(4): 52-56.  DOI: 10.3969/j.issn.1006-1355.2017.04.011 Abstract ( )   PDF (1276KB) ( )   Micro-cantilever is a kind of micromechanical device which is widely used in the research of force microscope and optomechanics. We employ system identification and modal parameters identification to micro-cantilever via ARMA model in order to knowing the modal information of micro-cantilever. Aiming at the problem that observing noise will decrease the identification accuracy of time series model, we studied the problem of converting the ARMA model with observing noise to the ARMA model without observing noise. After obtained micro-cantilever’s ARMA model, this model was converted to a transfer function of continual system, then micro-cantilever’s modal parameters were calculated from the transfer function. A recovery filter was constructed on the basis of the model obtained by system identification in order to decrease the delay time of micro-cantilever response to external force. The applied force signal was output by inputting displacement signal into the recovery filter. Simulation result and experimental result show the effectiveness of system identification, modal parameter identification and signal recovery method presented by this paper. Related Articles | Metrics

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Flow-excited Vibration Test and Simulation Analysis of an Underwater Open Cavity 2017, 37(4): 57-62.  DOI: 10.3969/j.issn.1006-1355.2017.04.012 Abstract ( )   PDF (2248KB) ( )   Related Articles | Metrics

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Experimental Study on Underwater Acoustic Radiation Suppression Performance of a Kind of Chiral Porous Coating 2017, 37(4): 63-68.  DOI: 10.3969/j.issn.1006-1355.2017.04.013 Abstract ( )   PDF (2524KB) ( )   Related Articles | Metrics

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An Analytical Method for Response Prediction of Coated Circular Plates to Underwater Explosion 2017, 37(4): 69-73.  DOI: 10.3969/j.issn.1006-1355.2017.04.014 Abstract ( )   PDF (1189KB) ( )   An analytical method is proposed to calculate the response of the coated circular plate subjected to underwater explosion. There are two effects on the response of the circular plate when the coating is laid. One is the effect on the impact load, the other is the effect on the response under the impact load. The analytical method employs the method of the wave propagating through multilayer mediums to calculate the pressure on the wetted surface and integrate the pressure to obtain the impulse. Then effective parameters of the system of the coating and the steel plate are obtained by the homogenization process. Finally, the response of the system is obtained given the initial conditions. Comparisons between the results obtained by the analytical method and the Finite element method indicate that the analytical method gives good approximations of the displacement response of the circular plate. Related Articles | Metrics

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Advances of Nonlinear Characteristics Research of Vehicle’s Suspension Components 2017, 37(4): 74-79.  DOI: 10.3969/j.issn.1006-1355.2017.04.015 Abstract ( )   PDF (1183KB) ( )   Related Articles | Metrics

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Prediction and Assessment of Core Engine Noise of Civil Aviation Turbofans 2017, 37(4): 80-84.  DOI: 10.3969/j.issn.1006-1355.2017.04.016 Abstract ( )   PDF (1650KB) ( )   With the turbofan design trends, the core engine noise level is greatly enhanced. So to analyze the turbofan core engine noise is important. In this paper, I divide the core engine noise into combustor and turbine noise, and then combine them into core engine noise, and I analyze the properties of CFM56-7B core engine noise, I compare the core engine noise with the combustor noise, turbine noise at idle, besides I compare the core engine noise EPNL at idle and at take-off. Related Articles | Metrics

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Influence of Metro Rail Corrugation on Track System’s Vibration and Mitigation Characteristics 2017, 37(4): 85-89.  DOI: 10.3969/j.issn.1006-1355.2017.04.017 Abstract ( )   PDF (2032KB) ( )   Rail corrugation characteristics of 3 types of track structure of the selected metro line including fix-dual short sleepers, Vanguard fastener and steel spring floating slab were investigated. The vibration experiments were carried out to analyze the influence of rail corrugation on track system vibration and mitigation characteristic. The results show that the depths of corrugation on the inner rail is much more obvious than those on the outer rail. The main frequency mostly depends on the wavelengths of corrugation. In the range of 4~200 Hz, the vibration damping track with short-pitch corrugation still have a good vibration damping performance. The mitigating vibration effect at high frequency is reduced obviously due to the short-pitch corrugation on the rail of Vanguard fastener track. There’s no obvious influence of long-pitch corrugation of steel spring floating slab track on vibration mitigation. And the greater amplitude of corrugation on the steel spring floating slab track caused increase of rail vibration. Related Articles | Metrics

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Study on Vibration Characteristics and Attenuation of Carbody’s Underneath Suspended Systems in Long-term Service 2017, 37(4): 90-94.  DOI: 10.3969/j.issn.1006-1355.2017.04.018 Abstract ( )   PDF (1590KB) ( )   Related Articles | Metrics

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Influence of Equipment Excitation on Vehicle Comfort Index and Equipment Vibration Severity 2017, 37(4): 95-99.  DOI: 10.3969/j.issn.1006-1355.2017.04.019 Abstract ( )   PDF (1698KB) ( )   Related Articles | Metrics

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Application of VA One in Ship Cabin Noise Prediction 2017, 37(4): 100-104.  DOI: 10.3969/j.issn.1006-1355.2017.04.020 Abstract ( )   PDF (1355KB) ( )   The basic theory of Statistical Energy Analysis is introduced in this paper. Combining with a ship model, the software, VA One, is taken out to predict ship cabin noise. Acoustics material, damping material and air-condition noise are analyzed. The results show ship cabin noise is reduced evidently when the acoustics materials are used. The ship cabin noise level difference is small under three different damping schemes, and taking weight of damping material into consideration, scheme 2 is much better. If the air diffuser with high noise reduction, superstructure noise level will hold on the line even turning on air-condition. Related Articles | Metrics

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Research on Longitudinal Damping Capability of a New Type Integrated Isolation System for Marine Thrust Bearings 2017, 37(4): 105-109.  DOI: 10.3969/j.issn.1006-1355.2017.04.021 Abstract ( )   PDF (1588KB) ( )   Related Articles | Metrics

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Analysis of Wheel Flat Induced Impact Noise Based on Acoustic Transfer Vectors 2017, 37(4): 110-114.  DOI: 10.3969/j.issn.1006-1355.2017.04.022 Abstract ( )   PDF (1767KB) ( )   Related Articles | Metrics

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Comparative Study on Several Calculation Methods for Ship’s Shock Spectra 2017, 37(4): 115-120.  DOI: 10.3969/j.issn.1006-1355.2017.04.023 Abstract ( )   PDF (1739KB) ( )   Related Articles | Metrics

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Analysis of Vibration Propagation Characteristics and Effect of Vibration Isolation Holes in Soil Foundation Reinforced by Dynamic Consolidation 2017, 37(4): 121-125.  DOI: 10.3969/j.issn.1006-1355.2017.04.024 Abstract ( )   PDF (1657KB) ( )   With the wide application of dynamic compaction method, the problem of environmental vibration caused by dynamic compaction get more and more attention. Through theoretical analysis and numerical simulation, the validity of the simulation is confirmed by comparing with the actual construction.Then study the effects of the compaction parameters include hammer diameter and tamping energy combination in the construction of tamping on environmental vibration by change the single variables in simulation,It was found that the bigger hammer diameter with the same weight and light hammer with higher drop distance is beneficial to reduce environmental vibration ; At the same way , The effect of three the parameters of vibration isolation hole which belong to discontinuous barriers include diameter,spacing and depth on the vibration isolation are analysised.The results demonstrated that the greater ratio of diameter to pitch of holes is better to effect of the vibration isolation when the depth of holes is constant.The research has guiding significance for guiding the construction of dynamic compaction and controlling the vibration of the environment. Related Articles | Metrics

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Analysis of Aerodynamic Characteristics and Galloping Performance for Two Typical Iced Stay Cables 2017, 37(4): 126-131.  DOI: 10.3969/j.issn.1006-1355.2017.04.025 Abstract ( )   PDF (2480KB) ( )   Related Articles | Metrics

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Analysis of Vehicle-Track-Bridge Coupling Vibration for the U-shaped Girder in Urban Rail Transit 2017, 37(4): 132-137.  DOI: 10.3969/j.issn.1006-1355.2017.04.026 Abstract ( )   PDF (1385KB) ( )   Related Articles | Metrics

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Study on Medium/High Frequency Dynamic Characteristics of Subway Tracks 2017, 37(4): 138-143.  DOI: 10.3969/j.issn.1006-1355.2017.04.027 Abstract ( )   PDF (2218KB) ( )   Related Articles | Metrics

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Dynamic Simulation and Fault Diagnosis of Planetary Gear Systems 2017, 37(4): 144-149.  DOI: 10.3969/j.issn.1006-1355.2017.04.028 Abstract ( )   PDF (1679KB) ( )   Related Articles | Metrics

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Sensitive Feature Extraction of Cross-head Slider Faults in Reciprocating Compressors Based on Wavelet Packets 2017, 37(4): 150-154.  DOI: 10.3969/j.issn.1006-1355.2017.04.029 Abstract ( )   PDF (1387KB) ( )   It was difficult to extract the effective features to the operation condition of the compressor by using analysis of the Traditional time domain or frequency domain ,Because the Vibration signal of reciprocating compressor is non-stationary and low SNR,. When the reciprocating compressor faulted, the distribution of signal's energy in the frequency was very different comparing with the normal state; In this paper, we proposed a method to extract the feature of multi band average energy based on wavelet packet analysis; Due sensitivity of each feature was different in response the running situation of compressor, a feature selection method was proposed based on Euclidean distance. The selected feature effectively reflected the running state of compressor. Finally, the feasibility and effectiveness of the proposed method was verified by the experiment of reciprocating compressor. Related Articles | Metrics

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State Prognosis of Rotary Machines Based on Long/Short Term Memory Recurrent Neural Network 2017, 37(4): 155-159.  DOI: 10.3969/j.issn.1006-1355.2017.04.030 Abstract ( )   PDF (1696KB) ( )   As a method of deep learning algorithm, long short-term memory network (LSTM) has been playing an increasingly important role in the field of time series prediction. This paper proposes a new method for state prediction of rotary machine based LSTM. The principle of LSTM applied to rotary machine state monitoring and prognosis is firstly introduced in this paper. In order to avoid the non-stationary of the bearing data , empirical mode decomposition(EMD) is used to decompose the bearing data into stationary singles ,and the intrinsic mode function (IMF) energy entropy is calculated as the feature of machine state. Furthermore the analysis of simulation results based on LSTM is compared with support vector regression machine (SVRM). LSTM has achieved a state-of-the-art prediction performance in the single-step prediction of rotary machine state.It shows that the proposed prognosis technology is superior in rotary machine state prediction and monitoring. Related Articles | Metrics

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Application of Variational Modal Decomposition and K-L Divergence to Bearing Fault Diagnosis of Vibrating Screens 2017, 37(4): 160-165.  DOI: 10.3969/j.issn.1006-1355.2017.04.031 Abstract ( )   PDF (2280KB) ( )   Related Articles | Metrics

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Application of Xgboost to Fault Diagnosis of Rolling Bearings 2017, 37(4): 166-170.  DOI: 10.3969/j.issn.1006-1355.2017.04.032 Abstract ( )   PDF (1434KB) ( )   Related Articles | Metrics

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Rolling Bearing Fault Diagnosis Method Based on MDS and Neural Network 2017, 37(4): 171-174.  DOI: 10.3969/j.issn.1006-1355.2017.04.033 Abstract ( )   PDF (1146KB) ( )   Related Articles | Metrics

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Application of Dimensionless Parameters Based on Genetic Programming to Fault Diagnosis of Planetary Gearboxes 2017, 37(4): 175-179.  DOI: 10.3969/j.issn.1006-1355.2017.04.034 Abstract ( )   PDF (1439KB) ( )   Related Articles | Metrics

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Fault Diagnosis of Marine Air Compressors Based on Vibration Signals 2017, 37(4): 180-184.  DOI: 10.3969/j.issn.1006-1355.2017.04.035 Abstract ( )   PDF (1631KB) ( )   Marine reciprocating air compressor has many excitation sources and complex structure, poor working environment, the characteristics of complex signal transmission path. These factors affect the signal analysis and fault source to determine. In order to extract the characteristic frequency, using the conventional method and the forced denoising, the default threshold denoising and the given soft threshold denoising method to deal with the vibration signal of the air compressor, By comparing the advantages and disadvantages of the four methods and the applicable conditions, it is found that the default threshold method retains the characteristic signal well and the noise reduction effect is good, so the default threshold denoising method is used to analyze the time and frequency domain of the vibration signal of the air compressor. Through the time domain analysis, it can be found 0.5 × rpm impact interval is obvious, by frequency domain analysis it can be found 1 × rpm frequency and with the emergence of 2 × rpm. The maintenance program can be presented according to the vibration mechanism of the air compressor and the historical maintenance record. The results show that the amplitude of the vibration and the frequency of the main frequency are significantly reduced, the maintenance effect is well. Related Articles | Metrics

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Study on Bandgap of One-dimentional and Two-component Phononic Crystal Based on the Inverse Transfer Matrix Method 2017, 37(4): 185-187.  DOI: 10.3969/j.issn.1006-1355.2017.04.036 Abstract ( )   PDF (1148KB) ( )   With sound transmission theories and research methods, the infinite periodic 1D two-component phononic crystal are studied from inverse problem, the planning methods are derived,the computer simulations are carried out from strucyure parameters. The results show that the bandgap of the infinite periodic can be studied from inverse problem, the bandgap study from structure parameter may design the 1D two-component phononic crystal. Related Articles | Metrics

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Design of Vibration Absorbers in Broad Frequency Band and Their Stiffness Control Based on MRE 2017, 37(4): 188-191.  DOI: 10.3969/j.issn.1006-1355.2017.04.037 Abstract ( )   PDF (1605KB) ( )   Related Articles | Metrics

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Optimization of Air Spring Orifice Diameter in EMU 2017, 37(4): 192-196.  DOI: 10.3969/j.issn.1006-1355.2017.04.038 Abstract ( )   PDF (1739KB) ( )   To address the problem that second suspension systems transform from damper to orifice. The dynamics model is established on the dynamics experiments and the dynamic characteristic experiments of air spring from a certain high-speed EMUs. The vertical stability and vibration acceleration were analyzed to elect the orifice diameter of air spring. Results show that the orifice of air spring exerts influences on both vertical damping and vertical stiffness. Analyzing the vertical stability, the stiffness and damping with 0.7Hz could be equivalent with its no-linear characteristic. After dislodging vertical damper, the orifice could effectively decrease vertical vibration RMS (Root Mean Square). When the running speed outnumber 150km/h, the advisable damping ranges of vertical damper is from 10Ns/mm to20Ns/mm, in addition, the apt orifice diameter of orifice is from 12mm to 16mm. After compering the two ways, it is recommended to select the orifice to provide damping. Related Articles | Metrics

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Vibration Reduction Effect of Cantilever Type Vibration Absorbers in Multi-frequency Band 2017, 37(4): 197-200.  DOI: 10.3969/j.issn.1006-1355.2017.04.039 Abstract ( )   PDF (1178KB) ( )   Related Articles | Metrics

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Experiment of an Isolator Fabricated with Diaphragm Bellows and Viscous Fluid 2017, 37(4): 201-205.  DOI: 10.3969/j.issn.1006-1355.2017.04.040 Abstract ( )   PDF (1850KB) ( )   For the purpose of protecting sensitive payloads from vibrations, a vibration isolator of large strokes, low dynamic amplification factor and high attenuation rate was proposed. Firstly, a two-parameter vibration isolator composed of diaphragm bellows and viscous fluid was fabricated and experimented. The isolator has approximately an attenuation rate of -30dB/dec at high frequencies and its resonance amplification factor is about 6dB. Next, on the basis of theoretical analyses, a three-parameter vibration isolator was presented by connecting the two-parameter isolator with a spring in series and increasing the fluid damping to improve isolation performance. As a result, attenuation of vibration transmission at high frequencies is enhanced and the amplification factor is reduced. Experimental results demonstrated that the amplification factor of the three-parameter isolator is less than 5dB and the attenuation rate is about -52dB/dec. Moreover, after isolation, the RMS values of acceleration responses are reduced by more than 90% in the frequency range of 0-500Hz. Related Articles | Metrics

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Noise Reduction Method for Air Duct Materials of Automobiles Based on 3D Finite Element Analysis 2017, 37(4): 206-208.  DOI: 10.3969/j.issn.1006-1355.2017.04.041 Abstract ( )   PDF (1352KB) ( )   Related Articles | Metrics

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Analysis and Control of Crankshaft Torsional Vibration Based on Frequency Response Functions 2017, 37(4): 209-213.  DOI: 10.3969/j.issn.1006-1355.2017.04.042 Abstract ( )   PDF (1636KB) ( )   Related Articles | Metrics

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Improvement of the Knock Sound Quality in Idle Performance    for a Motorcycle’s Single-cylinder Gasoline Engine with a Balance Shaft 2017, 37(4): 214-217.  DOI: 10.3969/j.issn.1006-1355.2017.04.043 Abstract ( )   PDF (1522KB) ( )   Related Articles | Metrics

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Development of Sporty Sound Quality for Exhaust Mufflers 2017, 37(4): 218-222.  DOI: 10.3969/j.issn.1006-1355.2017.04.044 Abstract ( )   PDF (1708KB) ( )   Related Articles | Metrics

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Interior Booming Noise Prediction via P/T Sensitivity 2017, 37(4): 223-226.  DOI: 10.3969/j.issn.1006-1355.2017.04.045 Abstract ( )   PDF (1454KB) ( )   Related Articles | Metrics

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Analysis of the Influence of Leakproofness of Cavities on Sound Transmission Loss in Compressor’s Suction Mufflers 2017, 37(4): 227-233.  DOI: 10.3969/j.issn.1006-1355.2017.04.046 Abstract ( )   PDF (1348KB) ( )   The suction muffler of a compressor was researched, the muffler is a 4-cavity structure, 2 of them are resonant cavities, the others are expanding cavities. To aim at the leakage between the cavities, the simulation analysis and experimental verification were carried out. It used LMS Virtual.lab to analyze their sound transmission loss, and had a compressor noise test in a semi-anechoic room. Comparative study shows that the leakage between the two resonant cavities can cause both of them failure，the leakage between the two expanding cacities can result in the sound transmission loss of them decreased, and the leakage between expanding cavities and resonant cavities can lead to the noise eliminating frequency of resonant cavities increase and that of expanding cavities decrease,if the two leaked cavities respectively connect to the import and export of muffler, the noise elimination peak of all cavities disappear, and the sound propagation loss would be dramatically decreased. Related Articles | Metrics