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18 October 2009, Volume 29 Issue 5 Previous Issue    Next Issue
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《CONTENTS》 2009, 29(5): 0-1.  Abstract ( )   PDF (2120KB) ( )   Related Articles | Metrics

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《Simulation and Experiment Study on Vibration Control of a Micro-Vibration Testing Platform》 LI Ping;WANG Xun;LI Zeng;ZHANG Zhi-yi 2009, 29(5): 1-3.  DOI: 10.3969/j.issn.1006-1355.2009.05.001 Abstract ( )   PDF (848KB) ( )   A micro-vibration testing platform with symmetrically placed electromagnetic actuators for the control of micro-vibration is presented. At first, a mathematical model of the micro-vibration platform is established for the simulation of micro-vibration control with an adaptive method. Then, an experiment is conducted to verify the control effectiveness. Both the simulation and the experiment demonstrate that the micro-vibration of the platform can be suppressed. Related Articles | Metrics

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《Approach of Whole Procedure Digital Simulation for Vibration Forecasting Using Power Injection Method》 XIE Meng-kai;YOU Jin;LI Hong-guang 2009, 29(5): 4-7.  DOI: 10.3969/j.issn.1006-1355.2009.05.002 Abstract ( )   PDF (1384KB) ( )   A numerical approach for determination of loss factors is presented by using the power injection method. The whole-procedure digital simulation for vibration forecasting is obtained. The U-shape pipeline is studied as an example to obtain the loss factors by using the power injection method by means of the ANSYS code. Then using the obtained loss factors as parameters, the statistical energy analysis of the U-shape pipeline is carried out by means of the AutoSEA software. Comparing the result of vibration response at the middle frequency and high frequency with that obtained by ANSYS code, it is found that the two results are essentially the same in the trend. The values of the two results are in perfect agreement in the high-frequency range. All of these results show that this method is feasible. Related Articles | Metrics

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《Influence of Base Impedance on Raft Isolation System》 GU Yaoying;HUANG Xiuchang;QIAN Zhenhua;HUA Hongxing 2009, 29(5): 8-12.  DOI: DOI:10.3969/j.issn.1006-1355.2009.05.003 Abstract ( )   PDF (1551KB) ( )   In order to alter the impedance feature of the base and the transmission properties from the excitation to the hull, an impedance changer represented by an M-K-C model is inserted between the lower isolator and the base of the raft system. In this paper, the influence of base impedance conversion on two single degree-of- freedom systems rested on an elastic base is studied. The result shows that the base impedance and the transmission properties from the excitation to the base have been changed, and the power transmitted into the base can be decreased at the resonant frequency of the hull. Similar conclusions can be made from the results of the raft system also. On this base, the influence of the impedance change of the base on the power transmitted to the base for complex raft system is studied. An optimization of the parameters of the impedance converser is made. This paper provides a theoretical reference for the design of the elastic base in raft vibration isolation systems. Related Articles | Metrics

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《Experimental Research on Cantilever-Beam Impact Damping System》 JING Xiao-hua;ZHENG Guang-hua 2009, 29(5): 13-15.  DOI: 10.3969/j.issn.1006-1355.2009.05.004 Abstract ( )   PDF (895KB) ( )   An experiment on cantilever-beam impact damping system was done. The displacement response of the damping system was measured. Some main experimental phenomena were analyzed. Related Articles | Metrics

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《Study on Impulse Response of Nonlinear System of Mobile Hard Disk with Rubber Isolator》 BAN Shu-hao;LI Xiao-yan;JIANG Xue-dong;YAN Guo-xin 2009, 29(5): 16-18.  DOI: 10.3969/j.issn.1006-1355.2009.05.005 Abstract ( )   PDF (1010KB) ( )   Employing the frequency hardening coefficient in the nonlinear dynamic system consisting of mobile hard disks with rubber isolator, a set of nonlinear differential equations for this system is established. The corresponding model for numerical simulation is constructed. The dynamic responses for different pulse durations and pulse magnitudes of acceleration are computed with this model. The influences of pulse signal parameters on the isolation effect are analyzed and discussed. Theoretical analysis and numerical simulation show that the model presented here is more reasonable than the traditional linear dynamic model. Furthermore, this model is simple and convenience for tation. It can be used to determine the natural frequencies of nonlinear vibration-tion system effectively. Related Articles | Metrics

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《Computation of Mechanical Impedance of Submarine Cabin Base at Low Frequency with FEM》 ZHANG Qing;PENG Xu;CHEN Ming 2009, 29(5): 19-22.  DOI: 10.3969/j.issn.1006-1355.2009.05.006 Abstract ( )   PDF (1404KB) ( )   Because of the difficulty to actuate the large structures in low frequency region, the mechanical impedance data of the large structures at low frequency has small coherence factor and low reliability. In this paper, a finite element code is used to establish an FE model for large cabin structure, and the mechanical impedance of a submarine cabin base in the low frequency region is calculated. The numerical results are compared with those of experimental measurement and theoretical assessment. The feasibility for forecasting the mechanical impedance characteristics of the base in the low frequency region by means of the finite element method is evaluated. The disadvantage of the low reliability of the measured mechanical impedance data of the cabin base at the low frequency is improved. This method is valuable for engineering application. Related Articles | Metrics

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《Analysis of Vibration Reduction Effect of Damped Wheels》 ZHANG Peng-Fei;LEI Xiao-yan 2009, 29(5): 23-26.  DOI: 10.3969/j.issn.1006-1355.2009.05.007 Abstract ( )   PDF (1444KB) ( )   Constrained damping treating is made on wheel’s surface for domestic standard wheels of passenger trains. Six types of damped wheels are designed. Standard and damped wheel models are built with ANSYS and the effects of thickness of damped layer, material and thickness of constrained layer on reducing wheel vibration are analyzed respectively. Then structural loss factors of these wheels are calculated by means of FEM method. The analysis has demonstrated that if the thicknesses of the damping layer and constraint layer are larger, the vibration reduction will be more effective. The effect of vibration reduction of such damped wheels with steel constraint ayer is obviously better than those damped wheels with aluminum constraint layer. And the structural loss factors of the damped wheels are much larger than those of the standard wheels. Most structural loss factors are above 0.003 under different working conditions within the frequency range of 1500 Hz to 5000Hz. Related Articles | Metrics

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《Dynamic Finite Element Analysis of Washing Machine Drums》 LI Xiao-chuan;ZUO Yan-yan 2009, 29(5): 27-29.  DOI: 10.3969/j.issn.1006-1355.2009.05.008 Abstract ( )   PDF (954KB) ( )   The drum of a washing machine rotates at a high speed during dehydration work, while the clothes in the drum rotate together with the drum, yielding pressure on the drum wall which causes the drum to deform. With software Pro-E and ANSYS the finite element model of a washing machine drum with its support is established. Dynamic analysis of the drum structure in the case of dehydration work is carried out. The natural frequencies and vibration modes are obtained. The critical positions and the critical rotating speed are found. Some improvement suggestions for the washing machine drums are esented. Related Articles | Metrics

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《Vibration-Acoustic Coupling Analysis of Conical Shell 》 HAN Feng;HU Dike;YAN Gui-rong 2009, 29(5): 30-33.  DOI: 10.3969/j.issn.1006-1355.2009.05.009 Abstract ( )   PDF (1453KB) ( )   The conical shell, as a typical structural component of spacecraft, may be excited by very strong noise in its operation, which will induce vibration-acoustic coupling of the structures and acoustic radiation. In this paper, the vibration-acoustic coupling models are built based on the FEM for the tructure and the BEM for the sound field. Numerical simulation of these models is carried out using Acoustic BEM Module in LMS virtual.lab code. The simulation results are verified with those of the noise test in the reverberation chamber. On this base the vibration-acoustic coupling characteristics of the conical shell is analyzed, and the structural responses of the coupled model are compared with those of the uncoupled model of the structure. The results demonstrate that the existence of acoustic fields influences the amplitudes and istributions of the structural responses, and the degrees of vibration-acoustic coupling exhibit different characteristics at different frequencies. Related Articles | Metrics

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《Nonlinear Dynamic Analysis of Fluid-Structure Coupled Vibration of Impeller System in Ventilating Fan》 GU Yong-xia;ZhOU Zhong-ning 2009, 29(5): 34-37.  DOI: 10.3969/j.issn.1006-1355.2009.05.010 Abstract ( )   PDF (1513KB) ( )   The features and laws of flow field and pressure pulsation within two counter-rotating rotors and tip vibration signals of blades under different conditions are analyzed. Some nonlinear dynamic analysis methods, such as phase-space reconstruction, correlation dimension, approximate entropy, and L-Z complexity, are mployed. The results demonstrate that the pressure pulsation and tip vibration are mutually related and coupled. Related Articles | Metrics

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《Analyses of Dynamic Responses of Subway Tunnels with Different Sections under Vibration Loading》 LIU Jin;CHEN Chang-zheng;ZHAO Hui 2009, 29(5): 38-42.  DOI: 10.3969/j.issn.1006-1355.2009.05.01 Abstract ( )   PDF (1591KB) ( )   Strength and deformation of soil around the subway tunnel is greatly affected by the vibration induced by the subway trains. In this paper, taking Beijing subway line 5 as an example, the dynamic responses of subway tunnels with rectangular and circular sections under train’s vibration loading are computed by means of the finite element code. The deformation of soil around the subway tunnels and the displacements of the ground surface are also given. The computation results for the two sections are analyzed and compared mutually. These results may provide some reference data for subway tunnel design。 Related Articles | Metrics

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《Study on Bifurcations and Chaos of Slideway-Joint System》 Zhang Wenge;Wang Yu;Shu Haiyan;Wang Shijun;Su Dan;Zhao Jinjuan 2009, 29(5): 43-46.  DOI: 10.3969/j.issn.1006-1355.2009.05.012 Abstract ( )   PDF (1262KB) ( )   The nonlinear dynamic behavior of the slideway-joint system of machine tools is studied. Taking into account the hysteretic characteristics of this system in contact vibration, a mathematical model for dynamic analysis is established. By means of asymptotic method, the coefficients of damping and stiffness equivalent to the hysteresis are obtained. Range-Kutta method is used to solve the system equation. The nonlinear dynamic responses of the guideway-joint system for different damping coefficients are discussed. The result shows that the chaotic vibration will occur when the damping oefficient varies in some range. Related Articles | Metrics

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《Using Unbiased Estimation Method to Calculate Frequency Response Functions of Simply Supported Beams》 HUA Guangjun;WU Jingping;WU Yunxin 2009, 29(5): 47-49.  DOI: 10.3969/j.issn.1006-1355.2009.05.013 Abstract ( )   PDF (830KB) ( )   A multi-input and multi-output unbiased frequency response function (MMUFRF) estimation is put forward based on the feature that the mean of the incorrelate signal CSD (Cross Spectral Density) tends to zero. The proposed method is realized by MATLAB programming. Two-input and four-output test is carried on using the dynamic signal test systems and its MMUFRF is acquired by MATLAB program. Meanwhile, numerical simulation of the frequency response functions is made by means of finite element method. The simulation results show that the proposed MMUFRF can correctly estimate the frequency response functions of real structures. Related Articles | Metrics

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《Active Vibration Suppression of Piezoelectric Laminated Plates》 GOU Xin-ke;CUI Ming-yue 2009, 29(5): 50-53.  DOI: 10.3969/j.issn.1006-1355.2009.05.014 Abstract ( )   PDF (1294KB) ( )   In the study, the flexural rigidity of piezoelectric laminated plate is derived based on the shear deformation theory of order one. The dynamic equation of the composite plate in a finite element form is deduced by using Hamilton’s principle, and the vibration-mode superposition method is employed. In order to get large driving force and efficient sensor signals, actuators and sensors are placed at the locations where the strain is locally maximum on the plate surface. Subsequently, an Independent Modal Space Control (IMSC) technique based Linear Quadratic Regulator (LQR) control methodology is adopted for the vibration suppression of the plate. The numerical example verifies the efficiency of this modeling and the method of control. Related Articles | Metrics

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《Power Flow Analysis of Inclined Elastic Isolation System》 CHEN Rong;SUN Ling-ling;ZHAO Fei;LI Zhi-bo 2009, 29(5): 54-57.  DOI: 10.3969/j.issn.1006-1355.2009.05.015 Abstract ( )   PDF (1292KB) ( )   A 3D dynamics model of inclined isolation system is established. This system includes multi-source excitation, inclined elastic supports and beams on flexible foundation, and the coupling effect among them is considered. The admittances of longitudinal vibration and flexural vibration of the isolator are provided. Considering the effect of multi-dimension wave propagation, the dynamic transmission matrixes and power flow of the system are formulated. Results of numerical simulation show that the standing waves of the isolator due to the high frequency resonance are the main reason of slowing down the tendency of power flow decrease. And in medium-high frequency domain, the power flow through the vibration source and foundation decreases with the increasing of the inclination of the supports. Related Articles | Metrics

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《Dynamical Response Failure Mode Based Reliability Analysis of a Cantilever Rotor》 ZHANG Pengfei;JING Jianping;MENG Guang;WANG Yuhua;ZHANG Lixin 2009, 29(5): 58-61.  DOI: 10.3969/j.issn.1006-1355.2009.05.016 Abstract ( )   PDF (1392KB) ( )   Cantilever rotor is the key component part of mechanical equipment. Based on the failure mode of dynamic response of the cantilever rotor, the ensitivity factors which affect structure reliability, such as load, size of structure, properties of materials, are analyzed. The utmost equations of the cantilever rotor in both static and dynamic states are built. Each equation is linearized at the average point by Taylor Expansion scheme. The reliability of structure is calculated by employing the theory of the primary second moment. The reliability results of considering and ignoring the inertial force respectively are compared mutually and analyzed. Then, an effective reliability analysis method for cantilever rotor is established. Related Articles | Metrics

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《New Method for Fault Diagnosis of Rotating MachinesBased on Harmonic Wavelet Filtering》 WANG Yu-rong;ZHANG Bo;ZHU Xue-jun;ZHANG Wen-bin 2009, 29(5): 62-65.  DOI: 10.3969/j.issn.1006-1355.2009.05.017 Abstract ( )   PDF (1390KB) ( )   A new method of fault diagnosis of in-situ sampled vibration signals is introduced for the non-stationery signals of rotating machines by using the harmonic wavelet filtering. Based on the nice box-shaped characteristic of spectrum of harmonic wavelet, the components in prescribed frequency region and other frequency components are decomposed to independent frequency bands without any overlapping or leaking. Then the frequency components in the prescribed region can be extracted by data reconstruction. Simulation results and practical examples show that this method has good filtering effect. It can extract the valuable frequency components for elementary fault diagnosis. This method has the merits of simple algorithm and computer-time saving. Related Articles | Metrics

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《Fault Diagnoses of Cracked Rotor and Rub-Impact Rotor Based on DEMD Method》 JING Bei-bei;LI Hong-guang 2009, 29(5): 66-69.  DOI: 10.3969/j.issn.1006-1355.2009.05.018 Abstract ( )   PDF (1156KB) ( )   The DEMD (Differentiation-based Empirical Mode Decomposition) is employed for fault diagnoses of cracked rotor and rub-impact rotor respectively. Firstly, the algorithm of DEMD is introduced. Then, the signals of cracked and/or rub-impact rotor are processed by using DEMD and EMD methods. The comparison of the results shows that DEMD method is better than the traditional EMD method for crack and/or rub-impact detection. Related Articles | Metrics

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《Fault Diagnosis of Diesel Engine Based on EMD and AR Modes》 LU Jin-ming;WANG Chun-tao;MA Jie 2009, 29(5): 70-73.  DOI: 10.3969/j.issn.1006-1355.2009.05.019 Abstract ( )   PDF (1455KB) ( )   The vibration signal of a diesel cylinder’s cover is a typical non-stationary signal. Traditional analysis of this signal in the time-frequency domain is not very effective. The interval analysis in time domain is not efficient either to realize real-time diagnosis. And it is also difficult to select the base function in wavelet transform. In this paper, the empirical mode decomposition (EMD) method is used to decompose the vibration signal into a number of intrinsic mode function (IMF) components and then the auto-regressive (AR) model of each IMF component is established. The auto-regressive parameters and the variance of remnant are regarded as the characteristic vectors and served as input parameters of SVM, and the working conditions and defaults of the diesel engine are classified. The results show that the proposed approach can classify working conditions of the diesel engine accurately, and effectively even in the case of small number of samples. And the real-time automation of the diesel engine fault diagnosis can be implemented. In order to classify the faults accurately, it is necessary to select new data as the training samples when the rotating speed of the diesel engine is changed. Related Articles | Metrics

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《Vibration Analysis of Turbine Feed Water Pump 》 MA Jun;TANG Xiongfei;ZHOU Pu 2009, 29(5): 74-76.  DOI: 10.3969/j.issn.1006-1355.2009.05.020 Abstract ( )   PDF (985KB) ( )   Feed water pump is one of important auxiliary equipments of steam turbine. In tuning up the feed pump of a steam turbine, over-vibration phenomena were found. In this paper, the vibration characteristic of the feed pump is analyzed carefully according to the vibration measurement data. It is found that the oil whip is the main cause of the over-vibration. The results provide a reference for tuning up and design of the feed pumps. Related Articles | Metrics

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《Fractional Cepstrum and Its Application in Machine Fault Diagnosis》 LIU Li-zhou;WANG Sui-ping;LI Zhi-nong;LIU Zhi-hua 2009, 29(5): 77-79.  DOI: 10.3969/j.issn.1006-1355.2009.05.021 Abstract ( )   PDF (1136KB) ( )   The definition and algorithm of fractional cepstrum are introduced. A new machine fault diagnosis method based on fractional cepstrum is proposed. The experimental result shows that fractional cepstrum is superior to the traditional cepstrum. It can suppress the interference and enhance the quality of the diagram spectrum. Related Articles | Metrics

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《Field Test of TrainInduced Building Vibrations and Investigation of Numerical Isolation》 FENG Mu;LEI Xian-Yan 2009, 29(5): 80-86.  Abstract ( )   PDF (2411KB) ( )   Firstly, using field testing, the vibration characteristics of the buildings, wavespropagation laws and influencing factors of structural vibrations nearby the trackline induced by moving trains are studied. Then, the traingroundtrench and barrierbuilding coupled dynamic model is established to analyze the influences of four structural parameters, such as the trench depth, the trench length, the distance from the trench to the building and the filledin materials, on the effect of isolation of the traininduced vibrations. The esults show that the structural vibration induced by moving trains is lowfrequency vibration; and the structures have attenuating functions to the highfrequency vibrations. Higher train speed, longer length of the train, and heavier load will induce larger structural vibrations. The increase of structural vibration level shows zigzag tendencies with the increase in floor elevation. The changes of trench depth, the trench length, the distance from the trench to the building and the filledin materials have large influence on the vibration isolation effect. Related Articles | Metrics

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《Study on Viscoelastic Constitutive Model of MR》 ZHAO Cheng;ZHANG Jun 2009, 29(5): 87-89.  Abstract ( )   PDF (881KB) ( )   Applying the tensioncompression viscoelastic model of metallic rubber (MR), the constitutive law of MR is obtained by means of ANSYS code with quilibrium iteration. The computation result is in good accordance with the experimental data. This work provides a reference for further study of MR. Related Articles | Metrics

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《Low Speed Dynamic Balance for Microwave Radiometer Imager》 LIU Jun;LIAO Ming-fu;WANG-Siji;WENG Yi-hang 2009, 29(5): 90-92.  Abstract ( )   PDF (989KB) ( )   Microwave radiometer imager is used for detecting cloud images in satellite for weather forecasting. Its mechanical scanning?component part is a bias parabolic reflector antenna with a large diameter, rotating at a low speed. Vibration amplitude is an important parameter of the microwave radiometer imager, overvibration will directly affect the satellite attitude control. It is proven that the vibration is mainly caused by dynamic unbalance. An insitu experiment for low speed dynamic balance of microwave radiometer imager is done. The results show that low speed dynamic balancing insitu is an effective method to reduce vibration of the microwave radiometer imager. Related Articles | Metrics

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《SelfAdapting Active Control of Exhausting Noise of Marine’s Diesel Engines and Its Experimental Study》 DENG Jun;SUN Zhao-Jun;WANG Bin;WANG Jing 2009, 29(5): 93-95.  Abstract ( )   PDF (1067KB) ( )   Exhaust noise of marines diesel engines is strongly related to rotating speed. Thus, the active noise control can be realized by composing secondary sound sources with the rotating speed signals as the base frequencies. But the difficulty lies on the determination of the weights of different sound sources. An arithmetic based on calculating the best errorweights is presented to overcome the difficulty. The results indicate that the method can effectively control exhausting noise and trace the change of diesel engines rotating speed. It adapts to the working conditions of marine propelling engines, whose rotating speeds are changing frequently. Related Articles | Metrics

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《Analysis and Control of Noise and Vibration of Hybrid Electric Vehicles》 XIONG Jian-qiang;HUANG Ju-hua 2009, 29(5): 96-100.  Abstract ( )   PDF (2197KB) ( )   The structural characteristics of hybrid electric vehicle (HEV) are analyzed in this paper. The changes of the noise and vibration sources and their characteristics due to the structural change are studied. The methods for controlling the noise and vibration of the HEV are put forward. Finally, the difficulty and the development trend of the noise and vibration control of the HEV are summarized. Related Articles | Metrics

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《Application of MATV and Acoustic Sensitivity Approach in Cab Interior Noise Analysis》 ZOU Ping;WEN Gui-lin;YANG Xing-fa 2009, 29(5): 101-104.  Abstract ( )   PDF (1371KB) ( )   Truck cab structures usually consist of plates, shells and beams. The traditional methods of structural modification of cabs to reduce the noise include adding mass and damping materials to the cabs and changing panel thickness of the cabs etc. These methods are somewhat blind when the optimal improvement positions are not yet known. In this paper, the MATV technique is used to determine the dominant panels, which have large contribution to the noise level, on the side of drivers right ear. Then, the BEM acoustic sensitivity analysis is utilized to search the positions of the structure which have the dominant influence on the specific sound pressure level. Using this method, the structure can be well improved for noise control. Related Articles | Metrics

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《Experimental Study on the Effect of Interior Noiseof Vehicles on Drivers Psychological Character》 OU Jian;YAO Jiang;ZHANG Yong;DENG Guo-hong;YANG E-chuan 2009, 29(5): 105-107.  Abstract ( )   PDF (1166KB) ( )   The testing of drivers attention quality and reaction character under vehicles interior noise condition are performed by means of psychometric detecting method. By analyzing the test data measured, the differences of these two parameters under different noise levels is obtained. The analysis and conclusion may have practical significance for improving driver’s traffic safety. Related Articles | Metrics

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《Testing and Analysis of Noise in a Commercial Vehicle》 ZHANG Yan;ZUO Yan-yan 2009, 29(5): 108-110.  Abstract ( )   PDF (991KB) ( )   A commercial vehicle is chosen for study. The interior noise is tested based on national standards. According to the results, the distribution and the spectrum characteristics of the interior noise are analyzed. Related Articles | Metrics

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《Analysis of Acoustic Characteristics of Marine Exhaust Silencers with AirFlow》 WANG Xue-ren;MIAO Xu-hong;JIA Di;JI Zhen-lin 2009, 29(5): 111-115.  Abstract ( )   PDF (1575KB) ( )   Influence of air flow on sound elimination effect of silencers with double expansion chamber is analyzed by means of the dual reciprocity boundary element method (DRBEM). The results show that the influence of higher Mach number subsonic flow on the sound elimination of complex silencers can not be ignored. Affects of the number of interconnecting tubes, inlet positions and the structural type of diversion annuluses on acoustic transmission loss of the silencers are summarized. Such conclusions are of some practical value for engineering application. Related Articles | Metrics

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《Application of Melamine Foam for Acoustic Absorption of Military Ship’s Engine Room》 YUAN Gai-hong;WANG Xian-cheng;ZHANG Jing 2009, 29(5): 116-120.  Abstract ( )   PDF (1785KB) ( )   Engine room’s noise is the main noise source. The noise signal of the engine room of a military ship is measured and its spectrum is analyzed. The main radiation frequency of the noise is found. The contribution of reverberation sound to engine room noise is studied. The scheme for reverberation sound control is worked out, in which a new damping soundabsorption material, the melamine foam, is utilized. Based on the statistical energy analysis (SEA), the geometrical model, the physical model and the mathematical model of the engine room are established. The software for simulating sound absorption of the engine room is made. According to the scheme of design, the melamineformaldehyde?foam coating is equipped in the engine room and then the noise testing is carried out. Result shows that the noise of the engine room is reduced 5.6dB(A). Related Articles | Metrics

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《Application of DAMAS Method of Microphon Array for Measurement of Airplane Noise》 SUN Shuang;QIAO Wei-yang;HUANG Xiao-dan 2009, 29(5): 121-126.  Abstract ( )   PDF (1595KB) ( )   A newlydeveloped method for microphone array  deconvolution method (Deconvolution Approach for the Mapping of Acoustic Sources, DAMAS) is introduced in this paper. Deconvolution method makes beamforming as preprocessing and extracts useful soundsource information from it. Then, a more accurate result can be obtained. Firstly, an experiment of noise measurement for the plane operating in static is carried out based on the microphone array, and the result is analyzed. The analysis is used to validate the feasibility and precision of the deconvolution method. Moreover, an average Doppler frequencyshift factor combined with the deconvolution method is applied to measure the overhead plane noise. The measurement result is compared with that by using traditional method. Related Articles | Metrics

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《Structural Optimization for Radiation Noise Control of a Simply Supported Plate》 Wu Wei-guo 2009, 29(5): 126-130.  Abstract ( )   PDF (1595KB) ( )   Structural optimization for radiation noise control of a simply supported plate is carried out using the time domain radiation modes. Recent study shows that these radiation modes in the time domain can radiate sound power individually, and the first order radiation mode is the dominant one. Based on these findings the design of Active Structureal Acoustic Control system is presented to cancel the first radiation modes amplitude by filter xLMS algorithm. And the optimization of arrangement of controlling force sources is analyzed and discussed. Finally, the validity of the proposed method is verified by a numerical example. Related Articles | Metrics

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《Analysis of Sound Power Sensitivity of Viscoelastic Damping Plates Based on Acoustic Radiation Modes》 QIU Liang;JIANG Zhe;YUAN Guo-qing 2009, 29(5): 131-135.  Abstract ( )   PDF (1612KB) ( )   The sound power sensitivity of viscoelastic damping plates is analyzed by using acoustic radiation modes. Two cases of plates, one with damping layer and the other with viscoelastic beams, are considered and compared. The influence of the thickness of the damping layer on the sound power sensitivity is found. The numerical examples show that it is effective for control of the sound power of plates by increasing suitably the thickness of the damping layer and locating reasonably the viscoelastic beams. Related Articles | Metrics

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《Approach Based on NonPrior Base Analysis for Improving Precision of Acoustic Holography Construction》 WANG Zheng-lun;ZHAO Xiao-dan 2009, 29(5): 136-139.  Abstract ( )   PDF (1370KB) ( )   Nearfield holography (NAH) measurement usually needs discrete Fourier transform (DFT) for spectrum analysis. When the signal is sampled in a nonsynchronous manner, the DFT spectrum analysis will yield leakage errors, which will reduce the reconstruction precision. A method based on nonprior base analysis is adopted. The base vectors are determined through searching the maximum peak value of the inner product. The covering effect of strong signals can be decreased, and the result is more accurate. This method is introduced to the NAH measurement to analyze the complex sound pressure on the holography surface. After that, the radiation sound field of point source is reconstructed. The result shows that the accuracy of sound field reconstruction is improved. Related Articles | Metrics

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《Application of Kirchhoff Formula in Prediction of Noise Level of Capacitor Installation》 SUN Xin-bo;WU Jiuhui;CHEN Hua-ling 2009, 29(5): 140-143.  Abstract ( )   PDF (1678KB) ( )   Kirchhoff formula method is employed to predict the surrounding fence noise level of the filter capacitor installation in the converter station. The computation results are compared with those by the monopole array sound source method, and by the measurement in Zaoqing. It is found that our computation results agree with the measurement data very well. Thus, this method is proved reasonable and correct. Related Articles | Metrics

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《Testing of Acoustic Properties of Sound Barriers and Data Analysis》 MA Ai-ying;GUO Huai-yong 2009, 29(5): 144-147.  Abstract ( )   PDF (1514KB) ( )   The main parameters for acoustics evaluating of sound barriers and their relations are briefly introduced in this paper. The methods for testing of acoustic properties of sound barriers are summarized. The data of testing is analyzed. It provides a reference for research and development of railway sound barriers. Related Articles | Metrics

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《Analysis and Control of Impact Noise of Hydraulic Pile Drivers》 HU Jun-ping;WANG Tao;HUA Shi-yang 2009, 29(5): 148-151.  Abstract ( )   PDF (1156KB) ( )   The importance of impact noise control of hydraulic pile drivers is elaborated. The theory of acoustic fluidstructure coupling and the corresponding finite element method are introduced. According to the theoretical characteristics of impact frequency spectrum, the relation of noise and buffer time is analyzed. Using the finite element software ANSYS/LSDYNA, the numerical simulation of impact of a pile driver is carried out. The results show that the impact noise can be reduced by prolonging the buffer time. Related Articles | Metrics

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《Experiment Investigate of the Absorption Properties of Water FilmAir Layered Structure Using Reverberation Time Method》 HE Wen-fang;DAI Tian-xing;LI Wan-peng;WANG Sun;GAO Xiang-xiang 2009, 29(5): 152-155.  Abstract ( )   PDF (1357KB) ( )   Water’s acoustic properties have been studied a lot. However, these studies were mainly focused on water’s properties of sound reflection and dissemination. Studies of sound absorption properties of composite structures made of water and other soundabsorbing materials are very few. In this study, a resonant absorption principle based novel water filmair layered structure is developed. By changing the thickness of water film, the absorption of this new structure can be modulated. Moreover, reverberation time experiments in a real scale test installation are designed to quantify the new structures diffusion absorption coefficients. The result shows that this multilayered composite structure produces a good absorption for low frequency sound, and the absorption properties depend on the water film thickness. Related Articles | Metrics

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《Acoustic Design for Anechoic Room》 YANG Zhi-hua 2009, 29(5): 156-159.  Abstract ( )   PDF (1346KB) ( )   Anechoic room is a special laboratory for acoustics testing. It is widely applied for the testing of acoustic properties of electroacoustic products and for the measurement of the sound power levels of noise sources. In the design of anechoic room, the acoustic principle should be obeyed, the requirement of application, the acoustic environment and the cost of construction should be considered. Taking an anechoic room construction as an example, some technical problems such as volume, type, sound absorption, sound insulation etc are discussed. An acoustic measurement is carried out after the anechoic room was completed. The measurement data shows that all the acoustic indexes are satisfactory or even better than those given in national standard. Related Articles | Metrics

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《Study on Extracting Partial Discharge Signals in Excessive Noisy Electromagnetic Environment》 YAN Nian-ping;YU Qin-xue;LI Wen-jie;TANG Chao 2009, 29(5): 160-164.  Abstract ( )   PDF (1661KB) ( )   Recently, more and more practical applications show that in excessively noisy electromagnetic environment, using wavelet transform (WT) only may bring waveform distortion. The Fast Fourier Transform (FFT) can suppress sinusoidal interference without concerning the signaltonoise ratio (SNR). Unfortunately, the FFT is almost helpless in suppressing white noise. Thus, combining the advantages of the two transforms, a new method to suppress both white noise and sinusoidal interference is presented. At first, the automatic threshold FFT is used to suppress sinusoidal interference partially and to raise the SNR. Then WT is used to suppress both the residual sinusoidal interference and white noise. Simulation results and practical applications demonstrate that this method can extract partial discharge (PD) signals effectively in excessively noisy electromagnetic environment. Related Articles | Metrics

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《Study on the Method of Noise Environmental Impact Assessment of Provincial Road Network Planning》 XU He;FENG Xiao-fei;BAI Hong-tao 2009, 29(5): 165-169.  Abstract ( )   PDF (1864KB) ( )   Noise environmental impact assessment (EIA) of provincial road network planning is a kind of strategic environmental assessment (SEA). However, its methodology is still in developing. Taking the main road network planning of Hubei province as an example and employing scenario analysis and empirically fitted FHWA model, the noise impact of the road network is predicted. The assessment is obtained by using GIS analysis. This assessment method provides a reference for noise environment impact assessment of the traffic planning in a large area. Related Articles | Metrics

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《Investigation of Evaluation Descriptors of Auditory Attribute of Underwater Noise in Chinese Environment》 WANG Na;CHEN Ke-an;HUANG Huang 2009, 29(5): 170-175.  Abstract ( )   PDF (2346KB) ( )   Suitable evaluation descriptors are very important for reasonable subjective evaluation of auditory attribute of underwater noise. In this paper, firstly, a large number of Chinese descriptors is gained by questionnaire surveys and using onhand soundqualityevaluation descriptors. And then, according to three elements of auditory attribute, loudness, tone and acoustic quality, 97 descriptors are selected for evaluating the auditory attribute of the noises. Secondly, in order to avoid the subjectivity, the selected descriptors are divided into 10 categories by using Paired Comparison approach and Cluster Analysis method. Finally, through questionnaire survey and replaying the selected descriptors, some commonly used descriptors are chosen from these categories as the evaluation descriptors of auditory attribute of underwater noise due to the highest selection probability. Related Articles | Metrics

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《Study and Practice on Noise Reduction and EnergySaving of a Boiler Room》 LI Ji;ZHANG Li 2009, 29(5): 176-177.  Abstract ( )   PDF (1076KB) ( )   The problem of noise pollution and energy waste of a boiler room in a residential area of Dalian city is studied in this paper. The causes which induce excessive noise and energy waste are investigated by analyzing sound source and propagation path of the noise. Then a method, that can reduce both internal and external noises of the boiler room and can save energy, is proposed. A good effect in engineering application is obtained. Related Articles | Metrics