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18 October 2014, Volume 34 Issue 5 Previous Issue    Next Issue

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Mode Analysis Method for Structure’s Sound Radiation Analysis Based on Source Intensity Acoustic Radiation Modes 2014, 34(5): 1-5.  DOI: 10.3969/j.issn.1006-1335.2014.05.001 Abstract ( )   PDF (1774KB) ( )   Velocity acoustic radiation modes may be used for solving the radiation problems of the structure, but it is very difficult to obtain the velocity acoustic radiation modes of the complicated structure, so source strength acoustic radiation modes method is proposed. The surface continuous source strength distribution of the structure was equivalent as source strength distribution of a set of simple sources in terms of simple source formula, and then the total time average acoustic power of the structure was obtained by means of this set of simple sources and a radiation resistance matrix was defined. Eigenvectors of the radiation resistance matrix constitute a set of acoustic radiation modes and those acoustic modes radiate acoustic power independently. Provided that the expansion coefficients are given, pressure and particle normal velocity and other acoustic quantities can be acquired by the proposed acoustic radiation modes superposition. Through analysis of acoustic radiation modes of a sphere and a truncated pyramid source, it is pointed out that the proposed source strength acoustic radiation modes retain the advantages of the traditional acoustic radiation modes and are more suitable for the research of the complicated structure radiation problems. Related Articles | Metrics

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Response Characteristics of Circular Plate with Various Covering Layers Subjected to Underwater Explosion XIAOFENG 2014, 34(5): 6-9.  DOI: 10.3969/j.issn.1006-1335.2014.05.002 Abstract ( )   PDF (1314KB) ( )   Flexible covering layers are usually covered on its hull surfaces to improve the shock resistance of a ship. In this paper，a research on the response characteristics of circular plate with various covering layers subjected to underwater explosion is carried out. The results will help clarify the interaction of underwater shock wave, bubble and the covering layers and also provide an interpretation of the shock mechanism of covering layers. Related Articles | Metrics

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Study on Friction Vibration of Shaft-hull Coupled System 2014, 34(5): 10-15.  DOI: 10.3969/j.issn.1006-1335.2014.05.003 Abstract ( )   PDF (1513KB) ( )   Related Articles | Metrics

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Adaptive High-precision Driving and Vibration Control Based on Giant Magnetostrictive Actuators 2014, 34(5): 16-21.  DOI: 10.3969/j.issn.1006-1335.2014.05.004 Abstract ( )   PDF (1700KB) ( )   Related Articles | Metrics

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Online Secondary Path Modeling Method for an  Adaptive Active Noise Control System 2014, 34(5): 22-26.  DOI: 10.3969/j.issn.1006-1335.2014.05.005 Abstract ( )   PDF (1318KB) ( )   Related Articles | Metrics

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Model Updating of Steel-tube Welded Structures Using Global and Local Modal Information 2014, 34(5): 27-33.  DOI: 10.3969/j.issn.1006-1335.2014.05.006 Abstract ( )   PDF (1826KB) ( )   For welded joints in steel tube welded structures, due to their complexity, the limitation of the sensors and inevitable errors, the model updating is always the hot and difficult problems which are considered by academy and engineering. Aiming to solve the above problems, in the model updating of the framework of a launch platform, global and local dynamic test were carried out, and the measured global and local dynamic information were summed up effectively for model updating by trust region optimization algorithm. In the process of optimization, by the proposed multi-objective function which have a dynamic changed weighting coefficient, it would automatic adjust with the orders of the objective function in every iterative step, and then the measured global and local dynamic information would be used more complete and efficient. The effectiveness and accuracy of the proposed method was verified by the results of model updating. Related Articles | Metrics

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Numerical Analysis of Influence of Tip Vane Width on Pulse Pressure of Pump’s Shroud 2014, 34(5): 34-37.  DOI: 10.3969/j.issn.1006-1335.2014.05.007 Abstract ( )   PDF (1205KB) ( )   Related Articles | Metrics

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Distributed Mass Model of Cantilever-beam Type Dynamic Vibration Absorbers 2014, 34(5): 38-41.  DOI: 10.3969/j.issn.1006-1335.2014.05.008 Abstract ( )   PDF (1070KB) ( )   Aiming at the problem that mass block of cantilever beam-type dynamic vibration absorber rarely meet the lumped mass assumption, this paper proposed a distributed mass model of cantilever beam-type dynamic vibration absorber. The method had considered the mass distribution characteristics of mass block and the influence on the stiffness of cantilever beam by mass block. Based on design constraints in engineering, parameters in the proposed model has been simplified, and the design parameters can be reversely determinated by design objectives without solving transcendental equation. Numerical examples show that the proposed model is significantly more accurate than lumped mass model. Related Articles | Metrics

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Optimal Design of Vibration Characteristics of Ship Bulkhead Structure with Rigid Vibration Isolation Mass 2014, 34(5): 42-46.  DOI: 10.3969/j.issn.1006-1335.2014.05.009 Abstract ( )   PDF (1505KB) ( )   Based on wave theory, the characteristics of rigid vibration isolation mass in impeding vibration wave propagation were studied and the influence of wave incident angle as well as sectional dimensions of isolation mass on its isolation performance was discussed. Furthermore, typical ship bulkhead with high transmission loss was presented with the introduction of rigid vibration isolation mass loop and rigid vibration isolation mass serration from the perspective of impedance mismatch. Finally, optimal design of isolation characteristics of typical ship bulkhead with high transmission loss was carried out through dynamic optimization method. The results indicate that the vibration of the power cabin is effectively reduced after optimization and the vibration propagation to the adjacent cabin is significantly impeded by optimal bulkhead obtained. Related Articles | Metrics

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Vibration Response Prediction and Control of a  Super Large Bulk Carrier 2014, 34(5): 47-50.  DOI: 10.3969/j.issn.1006-1335.2014.05.010 Abstract ( )   PDF (1670KB) ( )   A finite element method was used to do numerical analysis of overall vibration characteristic and forced vibration response induced by main engine exciting force of a 209000DWT Newcastle-Max type bulk carrier in this paper. Some key technologies were discussed, such as vibration analysis mechanical model,main engine frame vibration calculation and exciting force applied method. The vibration reduction effects of balance compensator and top bracing were evaluated. The results indicate that the vibration characteristic of this ship meets the requirement of ISO 6954 after using the vibration reduction method. Related Articles | Metrics

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Acoustic Sensitivity Analysis on Dominant Transmission Paths for Noise Reduction Design of Super-large Crude Carrier 2014, 34(5): 51-56.  DOI: 10.3969/j.issn.1006-1335.2014.05.011 Abstract ( )   PDF (1562KB) ( )   Related Articles | Metrics

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Parameters Optimization and Semi-active Control of Suspensions Based on Road Friendliness 2014, 34(5): 57-60.  DOI: 10.3969/j.issn.1006-1335.2014.05.012 Abstract ( )   PDF (1108KB) ( )   To improve the road friendliness of the commercial vehicle, this paper used a heavy duty truck as the research object, established the dynamic model of 1/4 vehicle, studied the influence of suspension parameters on the road friendliness. The suspension stiffness and damping have be optimized. Then base on the adjustable damping shock absorber, the semi-active suspension control was applied to improve the road friendliness. The results show that, compared with the passive suspension, the road damage coefficient of optimal fuzzy control semi-active suspension is greatly reduced, the ride comfort also has some improvement at the same time. Related Articles | Metrics

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Objective Evaluation and Analysis of Interior Sound Quality  of Rail Vehicles 2014, 34(5): 61-64.  DOI: 10.3969/j.issn.1006-1335.2014.05.013 Abstract ( )   PDF (1310KB) ( )   Related Articles | Metrics

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Modal Contribution Analysis of Intercity Rails under Working Conditions Based on ODS FRF 2014, 34(5): 65-69.  DOI: 10.3969/j.issn.1006-1335.2014.05.014 Abstract ( )   PDF (1164KB) ( )   For the study of modal contribution problems on Intercity Rail under working conditions,Firstly, Intercity Rail has been done exciter experiment On the shelf Statically and identified its modal parameters with LMS.Test.Lab.Then tracked its line experiments, tested acceleration vibration response under different speeds level. According to ODS FRF concept ,Its Operational Deflection Shapes has been gived at the ODS FRF envelope curve peaks. Finally, according to the modal superposition principle,A conclusion that typical ODS of the Intercity Rail under different speeds level are contributed by Body ups and downs,Body nod and Body vertical bending of order 1 was obtained. While the results also showed that ODS with the same frequency maybe contribution by different modes and the same frequency of ODS maybe occur offset under different speeds level. Related Articles | Metrics

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Analysis of a SUV Seat Shaking 2014, 34(5): 70-73.  DOI: 10.3969/j.issn.1006-1335.2014.05.015 Abstract ( )   PDF (1322KB) ( )   The problem of vibration occurred at front seat without passenger for a certain SUV during acceleration, and it badly affected the quality of the whole vehicle. The resonance phenomenon was studied by interior vibration test, modal test and CAE analysis, the resonance was caused by the swing modal frequency of front seat with suspension frequency of the vehicle. Finally, it was proposed to optimize the structure of front seat to change the natural frequency and increase vibration absorbers away from the suspension vibration frequency to avoid resonating, the test result showed that the amplitude was extremely reduced by 2.5m/s2 and subjective appraised that the vibration was eliminated. Considering cost、period synthetically, the project of strengthening for front seat frame was choosed. Related Articles | Metrics

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Identification of Road-induced Interior Structural Noise for Battery Electric Vehicle 2014, 34(5): 74-77.  DOI: 10.3969/j.issn.1006-1335.2014.05.016 Abstract ( )   PDF (1194KB) ( )   The noise resource and structure of battery electric vehicle (BEV) are different from internal combustion engine vehicle. As a result of the motor noise reduction, road-induced interior noise of BEV becomes more prominent. The spectrum analysis of interior noise for a type of BEV is carried out under different conditions. It is shown that the interior noise depends mainly on the contribution from road-induced structural noise in the low and mid-frequency range. By analyzing dynamic structure characteristic of BEV body and panels, the vibration sources and effecting factors of road-induced interior structural noise are indentified. The study provides the direction of optimization and control for BEV interior structural noise. Related Articles | Metrics

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Simulation of Low Frequency Structure-acoustic Coupled Vibration for Driver’s Cab of a Diesel Locomotive 2014, 34(5): 78-81.  DOI: 10.3969/j.issn.1006-1335.2014.05.017 Abstract ( )   PDF (1530KB) ( )   Through setting up the diesel locomotive structure-acoustic finite element model, applying the X,Y,Z orientation unite load on the point where the underbed and bogie were connected, the 30Hz～150Hz sound field response was computed. By analyzing the structure-acoustic model, drivers' cab vibration response, acoustical model of cab and cab sound filed response show that the cab sound level has obvious peaks at 68Hz, 76Hz, 86Hz, 98Hz, 124Hz because of the resonance of drivers' cab structure. Due to the structure and acoustical cavity of drivers' cab resonance ,the sound level sharply increase at 98Hz, 124Hz. The conclusion has a good reference value to the drivers' cab vibration and noise reducing. Related Articles | Metrics

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Measurement and Analysis of Vibration Transfer in the Tunnel of Suzhou No. 1 Metro 2014, 34(5): 82-85.  DOI: 10.3969/j.issn.1006-1335.2014.05.018 Abstract ( )   PDF (1859KB) ( )   In order to study the effect of the different damping measures of Suzhou rail transit line one, hammering method was used to test the transfer function and coherence between excitation point to the rail, sleeper, ballast bed, tunnel sidewall of short sleeper section (I type shock absorber fastener and elastic short sleeper monolithic roadbed) and long sleeper section (DTIII type fastener and long sleeper monolithic roadbed). The results showed that, the rail vibration attenuation from fasteners was mainly reflected in the low frequency range that less than 100 Hz, while the sleeper had better damping effect for frequency more than 100 Hz. Compared the transfer functions of two different test sections, I type shock absorber fastener and elastic short sleeper monolithic roadbed had better damping effect, in the 40 Hz ~ 80 Hz frequency range which particularly concerned , the decrease of peak vibration achieved 10 dB. Related Articles | Metrics

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Multi-objective Optimization of Powertrain Mount System Based on Vibration Isolation 2014, 34(5): 86-90.  DOI: 10.3969/j.issn.1006-1335.2014.05.019 Abstract ( )   PDF (1196KB) ( )   Related Articles | Metrics

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Noise Distribution Analysis of Air Conditioning Systems in Metro Cars 2014, 34(5): 91-94.  DOI: 10.3969/j.issn.1006-1335.2014.05.020 Abstract ( )   PDF (898KB) ( )   Test the noise of the metro cars air conditioning using noise and vibration analysis system at different speed and conditions, and conduct a spectral analysis of the noise characteristics of its air-conditioning system, and get their distribution. Stationary noise level distribution of air-conditioning systems are mainly concentrated in the frequency range of 160Hz-2000Hz, Air conditioning system noise has little effect on passengers standing and sitting, about 1.5 ~ 2dB (A) , Vehicle air conditioning noise is obvious，when running at low speed，and the speed is lower the greater the impact at low speed. The research results have certain reference value for metro vehicle vibration and noise reduction design. Related Articles | Metrics

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Low-frequency Noise Reduction in a Heavy Duty Truck’s Cab    with Damping Treatment 2014, 34(5): 95-98.  DOI: 10.3969/j.issn.1006-1335.2014.05.021 Abstract ( )   PDF (1367KB) ( )   A low-frequency noise controlling method based on modal analysis is proposed in the paper, which was applied to a truck with serious booming noise in the cab during idle speed. Firstly, the frequency information of the interior noise was obtained through noise testing and FFT analysis. Then the modal analysis was carried out on the cab body-in-white to determine the participation positions of the modal near the noise peak frequency, and damping treatment is implemented on those areas to reduce the structure-borne noise. Finally, the noise test on the truck after treatment was carried out to evaluate the scheme effect. The test results show that the noise peak value of main frequency decreased by 5.4 ~ 7.5 dB (A), therefore the low-frequency noise of the cab is controlled successfully. Related Articles | Metrics

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NVH Performance Study of a Heavy-duty Truck’s Powertrain Mount 2014, 34(5): 99-101.  DOI: 10.3969/j.issn.1006-1335.2014.05.022 Abstract ( )   PDF (1044KB) ( )   In this paper, the powertrain mount system of a heavy duty truck is studied. The vibration isolation principle of system and the fundamental principles for design are analyzed theoretically. Furthermore, through simulation computation and real testing on the vehicle, the frequency distribution of powertrain rigid body modal, energy decoupling degree of each modal, the vibration isolation rate of each powertrain mount and the vibration RMS values of the key points in cab, are studied under two conditions: the truck’s powertrain is installed according to 4 point suspension arrangement / 4+2 point suspension arrangement. The results showed that 4 point suspension arrangement, compared to the other one, is better for vehicle traveling on a nice even road. However, 4+2 point suspension arrangement is recommended to alleviate vibration of the vehicle from an uneven road. Related Articles | Metrics

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Noise Control for Large Flux Exhaust Pipe with Chocked Jet 2014, 34(5): 102-105.  DOI: 10.3969/j.issn.1006-1335.2014.05.023 Abstract ( )   PDF (1352KB) ( )   For noise trouble in high-temperature and high-pressure combustion lab， measurement of noise source was conducted. A muffler consisting of porous resonator and porous exhaust pipe was designed to eliminate harsh high-frequency noise generated by orifice plane and reduce general noise. As a result，the noise SPL was reduced by 21dB and the experiment environment was obviously improved. The design process of different muffler’s combination provides a reference for similar laboratory’s noise control. Related Articles | Metrics

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Prediction of Flow Noise in a Controlling-valve Using CFD Method JiadianWANG 2014, 34(5): 106-109.  DOI: 10.3969/j.issn.1006-1335.2014.05.024 Abstract ( )   PDF (1185KB) ( )   Aerodynamic Noise of a control valve is predicted using commercial CFD software together with ascoustic software. Two computation methods: one based on transient CFD calculation, the other based on steay CFD calculation are used in prediction. The computation results are compared with measurements, benefit and constraint of two methods are also compared. Related Articles | Metrics

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Numerical Simulation of Sound-absorbing Property of Membrane Materials 2014, 34(5): 110-113.  DOI: 10.3969/j.issn.1006-1335.2014.05.025 Abstract ( )   PDF (1369KB) ( )   In order to study the sound absorption ability of membrane materials, the sound absorption abilities of single-leaf and double-leaf membrane with or without air-back cavity are studied by numerical simulation. Results show that the resonance frequency moves toward low frequency region with the increasing of the mass density of membrane materials and the depth of air-back cavity when other parameters keep invariant. The sound absorption bandwidth of double-leaf membrane structure is wider than single-leaf structure. The sound absorption coefficient of two-leaf membrane without air-back cavity sound absorption structure remain unchanged as the frequency is below a certain value Related Articles | Metrics

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Vibration Analysis of a Dual-axial Fatigue Loading System for Wind Turbine’s Blades Test 2014, 34(5): 114-116.  DOI: 10.3969/j.issn.1006-1335.2014.05.026 Abstract ( )   PDF (1302KB) ( )   Related Articles | Metrics

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Prediction and Evaluation of Sound Quality of Diesel Engines Based on Neural Network 2014, 34(5): 117-119.  DOI: 10.3969/j.issn.1006-1335.2014.05.027 Abstract ( )   PDF (1066KB) ( )   Artificial Neural Network (Artificial Neural Network, referred ANN) is based on imitation of the structure and function of brain networks established an information processing system. In this paper, multiple linear regression and artificial neural networks were set up diesel engine noise sound quality prediction model, the predicted value and the measured value and compare the two models. The test results show that the system can reflect the nonlinear relationship between objective and subjective satisfaction between the parameters that can be used to predict and describe the sound quality of the diesel engine noise. Related Articles | Metrics

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Analysis and Control of Noise Pollution of an  110 kV Substation 2014, 34(5): 120-124.  DOI: 10.3969/j.issn.1006-1335.2014.05.028 Abstract ( )   PDF (1201KB) ( )   In order to master the level of transformer noise of 110kV substation, the transformer and boundary noise of the substation in normal operation were measured and the actual results were calculated and analyzed. The results show that the 110kV transformer noise was mainly concentrated in the frequency range of 100~2000Hz, which was more influenced by cooling fan and Electromagnetic noise. Most of the boundary noise exceed the national emission standard. At last the features spectral characteristics and transmission laws of the noise form 110kV substation's transformer were studies. And the major ways and methods are proposed to let the noise at boundary meet the standard by the predicting formula of noise, which provides a reference for noise control during the designing and constructing process of substations. Related Articles | Metrics

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Seismic Responses and Anti-seismic Performance of Recycled Concrete-filled Steel-tube Arch Ribs 2014, 34(5): 125-129.  DOI: 10.3969/j.issn.1006-1335.2014.05.029 Abstract ( )   PDF (1326KB) ( )   Recycled aggregate concrete is filled in steel tube structure to form recycled concrete-filled steel tube structure, the recycled concrete-filled steel tube arch rib seismic performance was studied. With a single span half-through arch bridge as project background, the calculation model structure was established, and it’s dynamic characteristics was analyzed, the bending moment response peak and shaft force response peak of the arch rib structure different sections were calculated, at the same time, the seismic evaluation curves of different regeneration aggregate replacement ratio recycled concrete-filled structure steel five yield phase were researched, by comparing the relationship between the internal force response peak and the seismic evaluation curves, the arch rib structure seismic performance was concluded The calculation results show that the recycled concrete applied to steel arch rib structure has good seismic performance, and it has little influence that steel tube arch rib is filled by recycled aggregate concrete with different substitution rate. Related Articles | Metrics

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Three-dimensional Numerical Analysis of Subway-induced Vibration of a Historic Building 2014, 34(5): 130-134.  DOI: 10.3969/j.issn.1006-1335.2014.05.030 Abstract ( )   PDF (1325KB) ( )   Taking a historic building near the subway of Nanchang Bayi square as research object, the three-dimension finite element model of rail-tunnel-ground-building including four tunnels was constructed and modal and transient dynamics analyses were conducted. In the situations of line 1 running, line 2 running and they running at the same time, the building vibration response was calculated respectively. The studies show that line 2 with shallow depth has a greater influence on the building vibration than line 1.Building vibration value will exceed limit value only when the line 1 and line 2 running at the same time and superscalar is not much. With the floor rising, building horizontal vibration shows a trend of decrease but the maximum value appears on the top floor. Related Articles | Metrics

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Research of Low-frequency Noise Control in KTV Rooms 2014, 34(5): 135-139.  DOI: 10.3969/j.issn.1006-1335.2014.05.031 Abstract ( )   PDF (1341KB) ( )   In KTV rooms, the noise pollution is mainly reflected in the low frequency between 63 Hz and 125 Hz, the volume can reach at 105dB or more, and the noise level produced from noise source boundary is above the threshold level causing the environment contradiction. There are some solutions in KTV rooms for low-frequency noise processing, and the mature noise treatment programs have been introduced. Firstly, sound insulation in KTV rooms which against its walls, ceilings, doors and floors；followed by the application of sound-absorbing material and its structure vibration isolation characteristics; the vibration isolation on audio devices; reduce acoustic leakage in rooms; the theory of phononic crystal plate with periodic novel spiral resonators and its application. Related Articles | Metrics

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Rolling Bearing Fault Diagnosis Based on Hilbert Spectrum Singular Value Decomposition SU Tao jun-zhong xia 2014, 34(5): 140-144.  DOI: 10.3969/j.issn.1006-1335.2014.05.032 Abstract ( )   PDF (1274KB) ( )   A feature extraction method based on Hilbert spectrum and singular value decomposition was proposed and applied to bearing fault diagnosis combining with the support vector machine. Firstly, the wavelet threshold de-noising method was used to extract the fault information from vibration signal. Then, the de-noised signal was decomposed into several IMF components through the empirical mode decomposition method, Hilbert transform was applied to each IMF component and got the Hilbert spectrum of the signals. The singular decomposition value method was used to the Hilbert spectrum to extract the time-frequency feature of the faulted bearing. Finally, the singular values were used as the feature vector to identify the different faults by using the support vector machine method with different kernel functions, the diagnosis result were analyzed and compared. The experimental results of bearing with inner-race fault, ball and out-race fault show that the proposed method is effective. Related Articles | Metrics

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Bearing Fault Diagnosis Based on EMD and Smoothed Pseudo Wigner-Ville Spectrum Entropy 2014, 34(5): 145-149.  DOI: 10.3969/j.issn.1006-1335.2014.05.033 Abstract ( )   PDF (1431KB) ( )   A method of fault diagnosis of rolling bearings based on empirical mode decomposition (EMD) and smoothed pseudo Wigner-Ville distribution (SPWVD) spectral entropy is proposed. EMD method fully retains the nonlinear and non-stationary characteristics of the signal, and has great advantage in the signal filtering and de-noising. Smoothed pseudo Wigner-Ville distribution (SPWVD) spectral entropy is used to quantitatively characterize the time-frequency energy distribution of the bearing vibration signal under different states. In this paper, two algorithms is applied to different working conditions of rolling bearing, and the intelligent model is designed based on least squares support vector machines (LS-SVM). It realizes the automatic classification and identification of bearing state and fault type. Through comparing method of SPWVD spectral entropy and spectral kurtosis, verified the effectiveness of SPWVD spectral entropy. The results show that this method can effectively extract the characteristics of the bearing fault information, and improve the rate of bearing fault diagnosis. Related Articles | Metrics

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Dimension Reduction Method for Rotor Fault Dataset  Based on LLTSA 2014, 34(5): 150-155.  DOI: 10.3969/j.issn.1006-1335.2014.05.034 Abstract ( )   PDF (1231KB) ( )   Characteristics of the data set dimension reduction is one of the key steps in mechanical fault intelligent diagnosis. It is difficult for the common data sets to reflect the operation state of sensitive information accurately from high-dimensional nonlinear dimension reduction method ,leading to reduce the precision of fault pattern recognition problem. Some scholars put forward on the part of the high-dimensional nonlinear data set can achieve better dimension reduction effect of local tangent space alignment (LTSA) algorithm. But the algorithm is not suitable for processing high curvature distribution, sparse uneven distribution of high dimensional data sources. this study combined the basis of the LTSA algorithm with linear block, and put forward the linear local tangent space alignment algorithm (LLTSA). The algorithm fully considered the whole and the local structure of a data set, and data sample space is divided into a set of linear block, making the dimension reduction of the similar data has better clustering. Domain data sets by high-dimensional nonlinear rotor vibration data to validate the algorithm, the results show that the data set after the dimension reduction algorithm has good clustering and classification performance. Related Articles | Metrics

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Analysis of Sensitivity of Combined Rotor’s Degradation to Crack Position 2014, 34(5): 156-160.  DOI: 10.3969/j.issn.1006-1335.2014.05.035 Abstract ( )   PDF (1520KB) ( )   Abstract: The crack has important effects on combined rotor degradation,so based on the bond graph,a general dynamic model for torsional vibration for combined rotor was established.Then, the position sensitivity of combined rotor degradation due to the crack on rod was studied. Research results show that the sensitivity of combined rotor degradation is decreasing while crack locates from each end to centre of the rod.However,the combined rotor degradation is in-sensitive to the crack position when the crack is too small.Furthermore, the less the number of rods and disks are, the higher the sensitivity of combined rotor degradation to the crack is . Related Articles | Metrics

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Milling Chatter Identification Method Based on Wavelet Packet Transform and Kernel Principal Component Analysis 2014, 34(5): 161-165.  DOI: 10.3969/j.issn.1006-1335.2014.05.036 Abstract ( )   PDF (1356KB) ( )   Related Articles | Metrics

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Fault Feature Extraction Method of Rotor System Based on Combination of Fractal and Geometrical Characteristics 2014, 34(5): 166-170.  DOI: 10.3969/j.issn.1006-1335.2014.05.037 Abstract ( )   PDF (1612KB) ( )   Fault signal of a rotor system is a typical nonlinear and non-stationary signal, The fractal geometrical theory can provide an efficient tool to characterize the feature of such a signal. However, relying solely on fractal dimension can not effectively extract the fault feature of the rotor system. Therefore, compactness and abundance are proposed, together with the mathematical-morphology-based fractal dimension adopted in the further analysis of the fault signal of the rotor system; finally, signals acquired from 5 different types of the rotor system conditions, such as normal, misalignment, imbalance, touch, loose, can be classified by neural network technology. The running status of the rotor system can be assessed by the joint of the mathematical-morphology-based fractal dimension, compactness and abundance. Experimental results reveal that this method has good discrimination capability. Related Articles | Metrics

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An Improved EEMD-based Denoising Method 2014, 34(5): 171-176.  DOI: 10.3969/j.issn.1006-1335.2014.05.038 Abstract ( )   PDF (1319KB) ( )   Related Articles | Metrics

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Quantitative Identification and Experiments of the Underwater Coupled Mechanical Noise Source 2014, 34(5): 177-181.  DOI: 10.3969/j.issn.1006-1335.2014.05.039 Abstract ( )   PDF (1337KB) ( )   To deal with the problem that the existing methods are difficult to identify main vibration sources and transmission paths of the submarine efficiently, putting the blind source separation (BSS) method merge with transfer path analysis method. Firstly, to improve existing BSS algorithms’ flaws, a class of simple Jacobi-type algorithms for non-orthogonal matrix joint block diagonalization based on the LU factorizations is presented, in which the signals of multi-vibration sources are regarded as convolution aliasing. After solving the uncertainty of sequence of separation vibration sources, an operational transfer path analysis method based on BSS is proposed, which can eliminate the effect of amplitude uncertainty on identifying vibration sources. Finally, the algorithm is successfully applied to identifying underwater vibration sources of submarine cabin model. The results demonstrate that the BSS algorithm established above has the merits of simplicity, effectiveness, and computational efficiency, which is much better than existing methods. The performance of the integrated source identification algorithm is superior to the algorithm whose vibration sources are coupling in underwater sound field prediction and the sequence of noise contribution. Therefore, the purpose for identifying mechanical noise source effectively and accurately is achieved. Related Articles | Metrics

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Dynamics Simulation and Fault Extraction of Teeth Fracture Fault of Planetary Gear Systems 2014, 34(5): 182-186.  DOI: 10.3969/j.issn.1006-1335.2014.05.040 Abstract ( )   PDF (1295KB) ( )   With the social development, planetary transmission equipment is increasingly used in civilian and military areas. But when working under high-speed and heavy-duty environment for a long period, its life will be greatly reduced, and will be accompanied by a high incidence of failure. Therefore, the demand to achieve prompt diagnosis has been increasingly urgent. However, failure mechanism of planetary transmission is still not rich enough, so the deep study is of great practical significance. Taking elastic deformation of planetary systems in the process of movement into account, through the introduction of flexible body in rigid body dynamics model, this paper establish a rigid coupling model and apply the rigid coupling simulation to planetary transmission model and planetary transmission model with broken teeth failure with ADAMS software. The sun gear and the planet carrier is set to be the flexible body, through fast fourier transformation, this paper analyze and compare the measured vibration signals, sum up the sun gear failure characteristics of broken teeth. Related Articles | Metrics

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Fault Diagnosis of Rolling Bearings Based on Spectral Centroid Histograms-SVM 2014, 34(5): 187-191.  DOI: 10.3969/j.issn.1006-1335.2014.05.041 Abstract ( )   PDF (1134KB) ( )   Early fault characteristics are usually immersed in heavy noise, owning lower SNR, which is difficult to diagnose. This paper analyzed the similarity of the existing methods and the way of visual information processing in order to improve the diagnosis accuracy of early fault diagnosis of rolling bearing. And it did some researches from the point of the way of vision information processing. A method of fault feature extraction of rolling bearing based on spectral centroid histogram is proposed, which is used for fault feature extraction of rolling bearing under different running condition. The extracted features are used as the input feature vectors of SVM in order to realize intelligence diagnosis in different running status. Experiments show that spectral centroid histogram improve the diagnosis accuracy of early fault of ball bearing, the accuracy increased 2%, which is better than MFCC features. Related Articles | Metrics

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Design and Experiment of the Actuator of an Incus Driving Type Middle Ear Implant 2014, 34(5): 192-197.  DOI: 10.3969/j.issn.1006-1335.2014.05.042 Abstract ( )   PDF (1797KB) ( )   The middle ear implantable hearing aids, as a new treatment for sensorineural hearing loss, has drew much attention of researchers home and abroad. A new kind of incus diving type middle ear implant, which contains a stack of piezoelectric crystals in a compact structure and a position adjustment apparatus, is established in this paper. Considering of the embedded location, space, and the implant surgery process, etc., its designing is comprehensively studied. Finite element method (FEM) is used to assess resonant frequency and output displacement of the device. It is shown that the designed apparatus can be implanted in the middle ear cavity. It has a good dynamic response, and the total harmonics distortion is well below 1%. Temporal bone experiment reveals that stapes displacement under actuator stimulation at 6.9Vrms was higher than that under acoustic stimulation at 90dB SPL over the operating frequency range, which can be applied to compensate the hearing loss. Related Articles | Metrics

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Comparison of the Vibration Reduction Effects of Particle Dampers under Swept-sine and Random Excitations 2014, 34(5): 198-202.  DOI: 10.3969/j.issn.1006-1335.2014.05.043 Abstract ( )   PDF (1374KB) ( )   Related Articles | Metrics

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Giant Magnetostrictive Actuator Design of an Active Micro-vibration Isolation Platform 2014, 34(5): 203-209.  DOI: 10.3969/j.issn.1006-1335.2014.05.044 Abstract ( )   PDF (1555KB) ( )   This paper presents a structure optimization of giant magnetostrictive actuator (GMA) and displacement amplifier applied in a 3-DOF active micro-vibration isolation platform. It subjects to a proposed design principle of minimum rate of energy loss based on the electromagnetic and mechanic coupling features from energy input to output of GMA system. The rate of energy loss is a function of a couple of important structural factors of GMA system. The energy loss rate reaches to 0.34 times lower than the design before optimization. Put optimizing dimensions into the dynamic model, the GMA output behaviors are also improved in terms of 2.28 times enhancement of displacement amplitude and 0.11 times attenuation of initial shock acceleration. These simulation results prove that the design method of optimization based on the minimum rate of energy loss is efficient, and the design actuator can well meet the requirements of the target vibration isolation platform for high efficient, stable and accurate displacement driving performance. Related Articles | Metrics

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Optimization Design of Muffler’s Structure of a Digging Machine Based on DOE 2014, 34(5): 210-213.  DOI: 10.3969/j.issn.1006-1335.2014.05.045 Abstract ( )   PDF (1290KB) ( )   Related Articles | Metrics

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Finite Element Analysis of Acoustic Attenuation Performance of  Conical Silencing Structure 2014, 34(5): 214-218.  DOI: 10.3969/j.issn.1006-1335.2014.05.046 Abstract ( )   PDF (1736KB) ( )   Related Articles | Metrics

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Silencing Performance Analysis of an Integrated Exhaust Purification Muffler 2014, 34(5): 219-222.  DOI: 10.3969/j.issn.1006-1335.2014.05.047 Abstract ( )   PDF (1476KB) ( )   Abstract: In order to achieve the dual function of diesel exhaust purification and exhaust noise reduction, designed the integrated exhaust purification muffler，modeled by FEM software，simulated sound field characteristic by sound field analysis software Virtual Lab. The impact from exhaust flow rate, temperature, outlet pipe reflex, intubation and cellular carrier on muffler performance were investigated， and thus the design of integrated exhaust purification muffler is verified reasonable. Related Articles | Metrics

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pplication of Dynamic Tuned Damper to Vibration Control of a Motor 2014, 34(5): 223-227.  DOI: 10.3969/j.issn.1006-1335.2014.05.048 Abstract ( )   PDF (1203KB) ( )   Related Articles | Metrics

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Inverse Algorithm in Estimation of Elastic Properties of  Materials Using Lamb Waves 2014, 34(5): 228-233.  DOI: 10.3969/j.issn.1006-1335.2014.05.049 Abstract ( )   PDF (1309KB) ( )   Based on the basic symmetric mode of Lamb waves, an inverse algorithm was proposed for calculating the elastic properties of different kind of materials. When Lamb waves propagate in the structure with complicated boundaries, components of the waves are difficult to distinguish due to overlapping. The basic symmetric mode (S0) wave is appropriate for estimating elastic properties of materials because of its relatively large group velocity. By using the phase spectrum method, the measured phase velocity can be extracted from experimental results. An error function depended on the measured phase velocity was introduced. The elastic properties can be inversed by minimizing the error function. In this paper, the inverse algorithm was tested in estimating the elastic parameters of thin aluminum plate, rotors and bogie, the results demonstrate the feasibility and generality of the proposed method. Related Articles | Metrics

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Impacting Factors of Damping Performance of  Constraint Damping Structures 2014, 34(5): 234-240.  DOI: 10.3969/j.issn.1006-1335.2014.05.050 Abstract ( )   PDF (1136KB) ( )   The variation about damping performance of constraint damping structure was study through the free bridge method in the paper, setting up damping layer thickness, the constraint layer material and environment temperature etc. Research showed that the damping performance of the constraint damping structure decreased with increasing the thickness of damping layer in 1 mm to 4 mm range; Damping performance of the constraint damping structure was different with constraint layer materials, respectively, for steel plate, marble slab and mortar; Low temperature, high temperature environment were not conducive to the damping performance of constraint damping structure; Better damping performance of the constraint damping structure was showed and composite loss factor was more than 1.540, in normal environment temperature. Related Articles | Metrics