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18 August 2012, Volume 32 Issue 4 Previous Issue    Next Issue
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1.综述
2.振动理论与数值解法

2.振动理论与数值解法
3.运载工具振动与噪声
2.振动理论与数值解法
3.运载工具振动与噪声



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1.综述

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Review for the Current Evaluation Methods of Vehicle Ride Comfort XIA Jun-zhong;MA Zong-po;FANG Zhong-yan;BAI Yun-chuan 2012, 32(4): 1-5.  DOI: 10.3969/j.issn.1006-1355.2012.04.001 Abstract ( )   In view of the controversy of ride comfort evaluation methods of domestic and international, the characteristics, differences and scope for each evaluation methods were analyzed. The integration of level of analysis and fuzzy is the typical subjective evaluation method. Then four object methods were described which were absorbed power method, the overall ride value method, VDI2057 (2002) and ISO2631 (1997). Finally several new subjective and objective comprehensive evaluation methods, including automotive integrated vibration comfort, fuzzy evaluation method and irritability rate analysis were introduced. The study found that every method is work, but the standard varies. The comprehensive evaluation methods can be better integrated to achieve the vehicle ride comfort evaluation, which may be the focus of future research directions. Related Articles | Metrics

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Comparison and Application on the Aero-acoustics Numerical Computing Methods XU Jun-wei;WU Ya-feng;CHEN Geng 2012, 32(4): 6-10.  DOI: 10.3969/j.issn.1006-1355.2012.04.002 Abstract ( )   The current aerodynamic noise problems have become more common and prominent. Although Lighthill created a pneumatic acoustics for more than half a century, but because of the complexity of the its equation, so over a long period of time it was unable to realize the accurate calculation of aerodynamic noise. With the maturation of the calculation method for computational fluid dynamics and acoustics, numerical computing is becoming the main tool to solve aerodynamic noise problems. This article, from the basic theory of pneumatic acoustics, the existing three pneumatic noise numerical calculation methods and their applicability were introduced. And through the application examples, their respective advantages and disadvantages and solving process were descibed. This may provide certain reference to the pneumatic noise forecast. Related Articles | Metrics

2.振动理论与数值解法

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Harmonic Analysis of Lateral Vibration of Floating Slab Track SU Yun;WU Tian-xing 2012, 32(4): 11-15.  DOI: 10.3969/j.issn.1006-1355.2012.04.003 Abstract ( )   The numerical model of the floating slab track (FST) lateral movement was established. Considering the torsional deformation of rail, the transverse displacement response as well as rail fasteners and steel spring supported force of rail head and FST excited by harmonic force were obtained. The results of numerical model were in agreement with the one obtained from the finite element model in ANSYS. Based on the harmonic response analysis to the numerical model under the different exciting force and the different supporting condition, the lateral movement status of the rail and EST in 0～500Hz frequency band were obtained. Related Articles | Metrics

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Application of Transfer Path Analysis in Structure Design LIU Rui-feng;ZHOU Pu;WANG Qiang 2012, 32(4): 16-19.  DOI: 10.3969/j.issn.1006-1355.2012.04.004 Abstract ( )   Abstract : Transfer path analysis (TPA) is an effective method for structure vibration performance optimization, evaluation and fault diagnosis. The basic theory and characteristic of TPA method is mainly described in the paper. The experiment system is established for TPA method to verify the TPA method. Comparison of simulation calculation value with experiment value shows that simulation result and experiment result are basically consistent. TPA method is used in four improved structures separately and reasonable structure is confirmed. The analytical results showed that the TPA method is a good way to find the vibration transmission path which provides the evidences to control the vibration transmission effectively. Related Articles | Metrics

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Study on Shock Response Characteristics of Nonlinear Rubber Isolator ZENG Cheng;HUA Hong-xing 2012, 32(4): 20-24.  DOI: 10.3969/j.issn.1006-1355.2012.04.005 Abstract ( )   To study on nonlinear shock response characteristics of rubber vibration isolators, taking into account the damping effect of nonlinear characteristics; a parameter model of 8 parameters was established , which was used to describe the shock response of rubber vibration isolator with displacement of hysteresis characteristics. Selecting a type of hard-rubber vibration isolators for the study, drop impact experiment was implemented with different conditions of shock response of rubber vibration isolators, as well as the impact of different speeds, shock stiffness under shock pulse width. Through optimal fitting of parameters, results showed that measured response is similar to the predictied value of the basic model. Related Articles | Metrics

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Dynamic Characteristics Research of U-shape Thin-wall Aqueduct under the Action of Fluid WANG Qing-yun; SUN Yuan-yuan; ZHOU Sheng-tong; BAI Xin-li 2012, 32(4): 25-30.  DOI: 10.3969/j.issn.1006-1335.2012-04-006 Abstract ( )   Two types of U-shape thin-wall aqueduct models with considering the action of fluid were established according to the potential-based fluid theory and Westergaard theory respectively. With these two models, modal analysis of the aqueduct was conducted, and the effects of water depth on the modal results were also analyzed. Comparing modal results of between these two models, it was found that: (1) the natural frequencies of aqueduct decrease with the increase of water depth; (2) the modal results of Westergaard model are lower than these of potential-based fluid model; moreover, (3) the effects of water depth on the natural frequencies corresponding to the same mode shapes are also different in these two models. On the basis of the comprehensive results comparisons and analysis, an improved Westergaard model (iWestergaard model) was proposed, results showed that the results of i Westergaard model are agree well with these of potential-based fluid model. Related Articles | Metrics

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Modal Analysis Method of a Globe Valve HE Hua;DING Wei;DAI Xue-chang 2012, 32(4): 31-33.  DOI: 10.3969/j.issn.1006-1355.2012.04.007 Abstract ( )   A finite element model of a globe valve is built, and the modal analysis of the globe valve is performed based on ANSYS. The calculation results are validated by the modal test. The results show that the valve stem isn’t as rigid as usually assumed. The calculation results are influenced greatly by the boundary conditions. Related Articles | Metrics

2.振动理论与数值解法

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Finite Element Analysis and Test on Dynamic Characteristics of Fuselage Frame of Unmanned Helicopter XIE Qin-wei; JIANG Nian-zhao;; ZHOU Guang-ming;ZHANG Xun; WANG Ke-xuan;ZHANG Zhi-qing 2012, 32(4): 34-36.  DOI: 10.3969/j.issn.1006-1335.2012.04.008 Abstract ( )   The finite element model of structural dynamics of fuselage frame of unmanned helicopter was established and the natural frequencies and mode shapes of its first 6 orders were obtained. Compared with modal test, the maximum error of calculation was less than 3 %. It shows that the finite element model is correct and accurately reflects the structural dynamics character of the fuselage frame of unmanned helicopter. The computational natural frequencies of frame avoided the natural frequencies of main rotor, tail blade and engine and can meet the request of dynamic of unmanned helicopter. The dynamic analysis method based on finite element analyses, which combines verification test and modal modification, can effectively guarantee the accuracy of the fuselage frame of unmanned helicopter. And it also provides the refrence for finite element dynamic modeling about other structure??of unmanned helicopter. Related Articles | Metrics

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Dynamics of Iced Transmission Line under Static Wind Loads MA Wen-yong; WEI Yao-yuan; MA Xiang-wang 2012, 32(4): 37-41.  DOI: 10.3969/j.issn.1006-1335.2012.04.-009 Abstract ( )   The static shape and dynamic characteristics of iced transmission lines under static wind loads were analyzed. The formulary of static shape of iced transmission lines under static wind loads was introduced with comparison of three analysis methods. Based on the analysis of dynamic characteristics of iced transmission lines under static wind, it was known that the inherent vibration analysis of iced transmission lines under static wind can more fully reflect the mode shape change with elastic wire geometry parameters and the relationship between modal coupling. That model can be used as basic function for establishing the discrete model of wire dynamic response analysis. Related Articles | Metrics

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Chaos Characteristics of Suspension Vibration under Quasi-impulse Excitation REN Cheng-long 2012, 32(4): 42-45.  DOI: 10.3969/j.issn.1006-1355.2012.04.010 Abstract ( )   The chaos characteristics of automobile suspension under quasi-impulse excitation were studied by numerical simulation and experiment. The 2D model of automobile suspension was built, which was subjected to the quasi-impulse excitation. The time history curve, power spectrum, phase trace and maximum Lyapunov exponent were given out by numerical simulation. It was confirmed that the automobile suspension vibration was chaotic. The vibration acceleration curve of automobile suspension was obtained by triangle wood experiment. The characteristics curves of suspension vibration were calculated and analyzed by using Matlab, and power spectrum and phase trace were obtained. And then the maximum Lyapunov exponent was calculated. The chaos characteristics of automobile suspension vibration were verified. Related Articles | Metrics

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Experimental Study of Passive Control Method of Pipeline Cavity Flow HUANG You;OUYANG Hua;WU Ya-dong;TIAN Jie;DU Zhao-hui 2012, 32(4): 46-50.  DOI: 10.3969/j.issn.1006-1355.2012.04.0011 Abstract ( )   Experiments were carried out in order to investigate the rectangular cavity flow of length-to-depth ratio of 5:1 using time-resolved particle image velocimetry (TR-PIV) technique. Three different passive control methods, including cylinder, sawtooth and rectangle body, were studied experimentally, having the same upstream velocity, i.e. 34 m/s. The experimental results show that the cylinder control method can increase shear layer thickness and effectively reduce the shear layer speed pulse and vorticity. Rectangle and sawtooth control methods will obviously raise shear layer to mainstream area, leading to no frontal impinging between the shear layer and the trailing edge of the cavity edge. Related Articles | Metrics

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Earthquake Shock Response Analysis of Diesel Engine Exhaust Silencing System ZUO Yan-fei; JI Zhen-lin 2012, 32(4): 51-55.  DOI: 10.3969/j.issn.1006-1355.2012.04.012 Abstract ( )   For some special applications with high safety requirements, it is necessary to investigate the structural response of the diesel engine exhaust silencing system under earthquake to ensure the reliability. The ANSYS/LS-DYNA software is used to calculate the structural response of the diesel engine exhaust system under the excitation of the Operating Basis Earthquake (OBE) and the Safe-shutdown Earthquake (SSE). The numerical results showed that the system can fulfill with the safety requirement under the earthquake, and there is no special stress concentration, the overall structural design is reasonable. Some suggestions for improvement are given out through the stress analysis. Related Articles | Metrics

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Inherent Vibration Analysis of Storage Tank in the Medium Consistency Pulp Conveying System FU Zhi-yuan;LI Hong;ZHUANG Hai-fei 2012, 32(4): 56-59.  DOI: 10.3969/j.issn.1006-1355.2012.04.013 Abstract ( )   To study on the solid-liquid coupling vibration of slurry storage tanks of medium consistency pulp conveying system, a simplified finite element model was built with ANSYS code. Inherent vibration analysis of storage tank was analyzed by reduction method, and the first 30 modes of storage tank were extracted. The results indicated that the most modes of the tank showed multiple circumferential waves, the shaking range of medium consistency pulp suspensions was rather weaker at the core then around edge. Compared with the theoretical formula, the numerical calculation result was reasonable. It may provide for further analysis of dynamic response of the tank. Related Articles | Metrics

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Numerical Simulation of Time-dependent Model of Work-piece During Turning LI Shun-cai; ZHUO Shi-chuang; JIANG Hong-qi; MENG Hua 2012, 32(4): 60-62.  DOI: 10.3969/j.issn.1006-1355.2012.04.014 Abstract ( )   The mechanical model and the time-varying differential equation of bending vibration was established. It was pointed out that the natural frequency and vibration modes have a time-dependent feature. Using the ABAQUS software the pre-stress effect modal analysis of the turning work-piece on the lathe was analyzed and the natural frequencies and vibration modes at different turning length were obtained. The calculation indicates that with the increase in turning length, the first-order natural frequency increased, then it decreased and curve of the natural frequency-turning length displayed as a parabolic distribution. Related Articles | Metrics

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Modeling of Arm System of Folding-boom Aerial Platform Vehicle MENG Shu-li;XIONG Jing-qi;LV Zhi-gang 2012, 32(4): 63-67.  DOI: 103969/j.issn.1006-1335-2012-04-015 Abstract ( )   With the flexible multi-body dynamics theory, the dynamic characteristics of the arm system of folding-boom aerial platform vehicle (FBAPV) were analyzed. The flexible multi-body dynamics equation of the arm system of FBAPV was established by with flexible multi-body dynamics theory and the Lagrange equations. Through the derivation and numerical solving of differential equation, the rigid and the flexible model were respectively given. Comparison of simulation results of both two models, the results indicate that considering the implications of each arm rods flexible deformation is necessary. Research results for FBAPV trajectory precision and oscillation control of table will have an effective reference. Related Articles | Metrics

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Incremental PID Neural Network Controller and Simulodion JIANG Chang-song;; LI You-de; LI Jing 2012, 32(4): 68-72.  DOI: 10.3969/j.issn.1006-1355.2012.04.016 Abstract ( )   According to the characteristics of the controllable three-levels damping vibration damper, the PID neural network controller based on the BP neural network of M×Q×3 structure is designed by using the neural network theory. According to the operation state of the controlled system, the PID controller parameters can be output through the neural network by the self-learning and the adjustment of the weighting coefficients of the neural network. A better control effect can be gained in this way. The effectiveness of this control algorithm is verified by the simulation analysis of three typical operating conditions for the passive suspension and the controlled suspension system. Related Articles | Metrics

3.运载工具振动与噪声

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Effect of Equipment Suspension Stiffness on Riding Quality WU Hui-chao;WU Ping-bo 2012, 32(4): 73-77.  DOI: 10.3969/j.issn.1006-1355.2012.04.017 Abstract ( )   In order to analyze the effect of equipment suspension stiffness on vehicle riding quality, the rigid-flexible coupling system dynamics model of EMU was established based on the modal calculation of the finite element model of EMU car body and using interface module of multi-body dynamics software SIMPACK. The coupling vibration between car body and equipments was studied, including different equipment suspension stiffness. According to comparative analysis of rigid and flexible two different join ways, it was found that the flexible suspension can depress the bending vibrations of car body, therefore can greatly reduce the equipment suspension influence to the car body. The optimization simulation results indicate that the equipment suspension stiffness has important effect on vehicle riding quality. Related Articles | Metrics

2.振动理论与数值解法

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Study on Characteristics Noise Radiation of Civil Aircraft Engine CHEN Ling;XIA Yu;JI Liang 2012, 32(4): 78-82.  DOI: 10.3969/j.issn.1006-1355.2012.04.018 Abstract ( )   In order to study the engine noise radiation characteristics of civil aircraft on the cruise state, a similar transformation law was used in which the engine state parameter measured on ground work was transfered to one of the flight state. Analyzing two known aircraft engines, the engine noise pressure level changes corresponding to the ground test state and the air cruise state were investigated with different speed and the radiation angle, and the noise radiation field change rule of these two kind of state was obtained. Related Articles | Metrics

3.运载工具振动与噪声

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Analysis and Control on Friction Noise of the EPS Motor LI Chuan-bing;; YAN Bing; LEI Ying-feng;; LI Shu-jing 2012, 32(4): 83-87.  DOI: 10.3969/j.issn.1006-1355.2012.04.019 Abstract ( )   The substitution of hydraulic steering system with electric power steering system is one of the most important measures of automobile energy conservation and emission reduction, but the former exists relative big noise shortcoming. For the problem of the abnormal sound, which is derived from a specific electric power steering system when rotating the steering wheel, via associating subjective evaluations with objective data and combining experiments with signal analyses, the source of noise was identified, the time -frequency property of the abnormal sound signal was obtained. The outcome shows that the cause of the noise derived from the electric power steering system is mainly the frictional force between the electric brush and the commutator, which arouses the structural vibration of the motor shell and its nearby assemblies. The abnormal sound of the electric power steering system was notably reduced by restraining the fractional force between the brush and the commutator and enhancing the rigidity of the motor shell, meanwhile, the acoustical behavior was also notably promoted, and was better than that of the similar imported motors. Related Articles | Metrics

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Structure-borne Noise Analysis and its Reduction of Tramcar Cab ZHANG Xue-qiu; CHEN Jian 2012, 32(4): 88-91.  DOI: 103969/j.issn.1006-1355.2012.04.020 Abstract ( )   For a tramcar cab interior, the coupled indirect boundary element method is used to compute coupled sound on the right ear of the driver inspirited by the force on the mounting closed to the cab, which is calculated using matrix inverse transfer method, and the focused frequency is found. The mainly positive contribution panel is found by analyzing panel contribution on the focused frequency. On this basis, the sound on the right ear of the driver at 80 Hz is reduced 12.82 dB by topography optimizing the roof and installing dynamic vibration absorber on the mainly positive contribution panel. Related Articles | Metrics

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Identification and Control of Interior Noise of the Home-made Car of Self-owned Brand WU Chao-qun; WANG San-long; XU Jin; ZHANG Xuan-guo 2012, 32(4): 92-95.  DOI: 10.3969/j.issn.1006-1355.2012.04.021 Abstract ( )   The source of interior booming noise in the development of a domestic car was identified. It was confirmed in the present research that the booming noise was caused by the exhaust noise. The structure of muffler was analyzed and optimized using GT-POWER. According to the results, a dual band Helmholtz resonator was proposed to eliminate the booming noise. It was found the interior noise was reduced by 6 dB and the NVH performance of the car was improved apparently. Related Articles | Metrics

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Analysis of Interior Noise in Low-frequency Range of EV Car ZHU Mao-tao; FAN Ting; WANG Zhong; LIU yi-fu 2012, 32(4): 96-102.  DOI: 10.3969/j.issn.1006-1355.2012.04.022 Abstract ( )   In view of the lower frequency problem of a micro-EV, using the finite element method (FEM), the acoustic modal was calculated ,then the acoustic frequency response of the cab was made . In order to reduce the vibration of the panel which radiates the noise most, BEM was used to calculate the acoustic contribution of the main panel of the car body, then to solve it by putting up damping material on the panel. By comparing the noise response, it is found that the damping material has significantly reduced the noise of the cab. Related Articles | Metrics

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Simulation Analysis of Acoustic Response on Automobile Cab LIU JIAN-wei ;; LIU Er-bao ;; WANG Zhi-liang ;; JIA Yan-bin ; 2012, 32(4): 103-106.  DOI: 10.3969/j.issn.1006-1355.2012.04.023 Abstract ( )   For the problem of higher noise level at the rear passengers’ ear, sound-structural coupling FEA model of vehicle was built. Then the main sonic transfer path at the left-front suspension setting location was obtained through acoustic sensitivity analysis, and the more contributing plates via PCA was found. Finally, the sound level was debased by improving damping material and which was proved by the vehicle performance test. By this way, the more contributing path and plates can be found conveniently and an effective way to evaluate and reduce the noise level of cab was provided. Related Articles | Metrics

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Influence of Incidence Angles of Door Closure Sound to Binaural Test Results of Artificial Head LIN Lei; YAN Bing; LIN Yu-hui; GU Yan 2012, 32(4): 107-110.  DOI: 10 3969/j.issn.1006-1355.2012.04.024 Abstract ( )   The binaural variation of the attributes, such as SPL, loudness and sharpness, which quantify the sound quality of door closure at different incidence angles, were changed. Based on the overall loudness perception model in dichotic conditions, the overall perception of loudness and sharpness was analyzed. The results show that the loudness and sharpness of each ear had a big change with the increase of incidence angel, while the overall perception had little change. Related Articles | Metrics

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Analysis on Tire Lateral Pattern Ditch Noise Influence Factor WANG Guo-lin; GAO Long; ZHOU Hai-chao; MAO Zhu-jun 2012, 32(4): 111-115.  DOI: 10.3969/j.issn.1006-13552012.04.025 Abstract ( )   A tire model which has lateral pattern groove was established by virtual of ABAQUS software and extracting the deformation curve of one groove's surface in the simulation process. A single groove and its ambient air field were established, loading the deformation displacement on the groove's surface. By means of FSI method, pumping noise was simulated with changing tire's velocity, pressure, load and friction coefficient. The results show that the SPL of noise increases as tire velocity increases, the SPL of noise increases as load increases, the SPL of noise increases as pressure changes, the SPL of noise doesn't change significantly as friction coefficient increasing. It shows that FSI method is feasible in analyzing tire pumping noise. Related Articles | Metrics

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Study of Radiated Sound Power and Its Sensitivity Analysis of Plate LIU Cong;JIANG Zhe 2012, 32(4): 116-120.  DOI: 10.3969/j.issn.1006-1355.2012.04.026 Abstract ( )   Joint using the finite element method and acoustic radiation modal method to solve the sound power structure sheet radiation, the structure radiation sound power about the design variable sensitivity was analyzed. In the structure vibration link, surface vibration velocity was obtained using the finite element method; in the sound radiation link, the sound field information about radiation of surface vibration can be obtained by expansions of the acoustic radiation modes. For the radiation of a stiffened panel, sound power sensitivity with respect to design variable was analyzed, and the results showed that the sound power was reduced by using stiffeners when the excitation frequency was far from the natural frequency of the body, but it had negative influence and was useless by using stiffeners when the natural frequency was close to the excitation frequency. Related Articles | Metrics

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Study on Noise Reduction Performance of Sound Barrier with Acoustic Diffusers WU Wen-gao;CAI Jun;LIU Ling 2012, 32(4): 121-125.  DOI: 10.3969/j.issn.1006-1355.2012.04.027 Abstract ( )   In this paper several kinds of basic common Schroeder diffusers were introduced, and the diffusers were applied on the top of sound barrier. Using boundary element method, the sound barrier structure model was simulated. Significant effects of noise reduction of all diffusers were found in low frequency range with 3～5dB higher than traditional sound barrier. Also it was found that prime root diffuser (PRD) has the better insertion losses up to 0.61~1.52 dB than other diffusers at the 5 m distance back of the sound barriers. The result will provide an important reference to apply sound diffusers on the sound barrier. Related Articles | Metrics

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Survey and Analysis on Noise Barrier Insertion Loss of Jiangsu Province Highway YANG Wen-ting;YIN Cheng-qi;CHEN Yuan;ZHANG Lin 2012, 32(4): 126-130.  DOI: 10.3969/j.issn.1006-1355.2012.04.028 Abstract ( )   Based on investigation of built highway noise barriers in Jiangsu province, the effect of several factors, including equivalent frequency, traffic flow, etc, on insertion loss of highway noise barriers were analyzed, and the revision was carried out. The results show that the sound source model reflecting characteristic of traffic noise is the key to assess acoustic performance of noise barrier. Meanwhile, there were some construction defects on a few of noise barriers, leading to sound leakage and poor acoustic performance. Related Articles | Metrics

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The Study of Monitor of Acoustic Environmental Effect During the Operation Service of Hainan Eastern Ring Railway zHANG Bo;TIAN Liang;DING Ping-gang 2012, 32(4): 131-134.  DOI: 10 3969/j.issn.1006-1355.2012.04.029 Abstract ( )   In order to know the regularity of the noise effect of Hainan Eastern Ring Railway, the field measurement of Haikou section was performed. The main conclusions included that the noise increase curve of the train operation period doesn’t present the sound source attenuation characteristic. In the urban area, through monitoring noise of running trains with the different number of the roadside trees, the noise of railway traffic could be reduced. Around the train running line, monitoring indoor noise at different floors, the different regularity of the noise effects was obtained. At the same time, the level of noise when increasing the number of trains per hour in the future was predicted. Related Articles | Metrics

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Optimization Design of Highway Noise Barriers Based on Response Surface Methodology ZHANG Lin;YIN Cheng-qi;TONG Kai;HU Jie 2012, 32(4): 135-139.  DOI: 0.3969/j.issn.1006-1355.2012.04.030 Abstract ( )   the Box-Behnken design and response surface method were applied to optimize the parameters of noise barriers. The height, length and initial stake of noise barrier were studied as arguments, while the insertion loss of three sound-sensitive points, construction cost as variables. Quadratic equation models were developed to express the functional relationship between arguments and variables. Optimization parameters of noise barrier were obtained by Minitab analysis, basing on the goals of acoustic environmental standard in sensitive area, as well as minimization of construction cost. Related Articles | Metrics

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Application of Wavelet Threshold Method in Processing Tracked Vehicle Vibration Signal LV Wei-wei;GU Liang;HUANG Xue-tao 2012, 32(4): 140-144.  DOI: 03969/j.issn.1006-1355-2012.04.031 Abstract ( )   n order to avoid an interference of strong noise to tracked vehicles vibration signal, using wavelet transform, several wavelet bases was compared according to reconstruction factors, then an appropriate wavelet base and threshold to processing vibration signals of tracked vehicles were determined, the wavelet layered method was described The simulation result indicated the wavelet transformation de-noising method can suppress the background noise effectively, extract useful state information, enhance the signal-to-noise ratio, reduce mean-square error and recover the interest weak signal buried in intensive background noise. Related Articles | Metrics

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GDA Research on Multi-scale Analysis of SEMG XU Ying-jie;LEI Min 2012, 32(4): 145-149.  DOI: 10.3969/j.issn.1006-1355-2012.04.032 Abstract ( )   one kind of fusion wavelet characteristic and the generalized distinction analysis （GDA） extraction method was proposed and it was applied to descript the efficiency of dimension reduction for multi-scale feature of SEMG. First, wavelet decompose was employed on SEMG, and the mean of absolute value for wavelet coefficient at each level was extracted as original feature vector, then the dimension by GDA was reduced, the new feature of lower dimension was obtained, which was used for classification by Bayes classifier. By selecting felicitous levels of wavelet decomposition as well as pretty kernel parameter and new dimension, it can result in good performance in the pattern recognition of six movements including wrist inward，wrist outward, wrist up, wrist down, fist clench and fist stretch with the accuracy of above 97 % for three testers. The research indicated that the proposed method can successfully acquire the main component of multi-scale SEMG and its feature. Related Articles | Metrics

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A Method of Eliminating Outliers in Data Processing of Vibration Signal Based on Wavelet Transform LV Wei-wei;GU Liang;HUANG Xue-tao 2012, 32(4): 150-152.  DOI: 10.3969/j.issn.1006-1355.2012.04.033 Abstract ( )   n tracked vehicle vibration signal data processing, the existence of outliers can produce false harmonic frequency components. By using wavelet transformation vibration signal is decomposed into approximate components and details components. With the Wright standards and the characteristics of outlier’s wavelet coefficients, outlier’s details components are replaced by new details components, which are calculated by weighting coefficient method. The outliers are removed and signal is reconstructed. Test data processing results show that the new method can maximum retain the useful signal information, realizing the outliers eliminate. Related Articles | Metrics

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Large Transformer Fault Diagnosis Identification Method HE Hong-jun; RAO Zhu-shi;SHAO Yu-ying ; JIN Gjian-ping 2012, 32(4): 153-157.  DOI: 10.3969/j.issn.1006-1355.2012.04.034 Abstract ( )   arge power transformer traditional electrical measurement fault diagnosis method not only process is complicated and still can't effectively identify the cause of the problem. Thus, based on a hidden Markofv model (HMM) and fuzzy set diagnosis, this paper puts forward more effective method for the fault recognition of transformer winding , namely detained recognition method. Through simulation and experimental validation, this method can make accurate state of transformer type of recognition. Related Articles | Metrics

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Modelling and Separation Processing of the Power Interference Vibration Signals LV Miao-rong;LI Mei 2012, 32(4): 158-162.  DOI: 10.3969/j.issn.1006-1355-2012.04.035 Abstract ( )   or drilling pump vibration frequency interference during testing, the rational segmentation of measuring signal is achieved by basic operation unit (BOU) method and the modeling analysis of the interference signals after subsection is realized by optimal frequency matching method (OFMM). Based on above work, the matching filtering method of vibration signal is put forward, and the matching filter separation of interference signal from drilling pump vibration signal is successfully accomplished. It is shown that OFMM is a new general processing method, which can construct different kinds of signals，modeling. Matching filter method basing on OFMM is a kind of new and adaptable signal filtering processing method which can also separate time and frequency domain signals relatively and completely. Related Articles | Metrics

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Application?of Spike?Energy Method?in?the?Air Compressor?Bearing?Fault?Diagnosis PAN Ben;YU Jie 2012, 32(4): 163-165.  DOI: 103969/j.issn.1006-1355-2012.04.036 Abstract ( )   ibration spike energy can be used to estimate the running state of the mechanical parts. Screw air compressor is the key power equipment in natural gas refineries. The diagnosis of bearing of screw air compressor was successfully predicted using spike energy method, and further damage to the equipment was prevented in early stage. Through engineering practice, it was proved that spike energy method is valuable in the diagnosis of bearing of screw air compressor. Related Articles | Metrics

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Vibration Faults Example Analysis of Pinghu Oil Gas Field Reciprocating Compressor GUAN Yao-hua 2012, 32(4): 166-168.  DOI: 10.3969/j.issn.1006-1355.2012.04.037 Abstract ( )   or offshore oil platform common reciprocating compressor vibration failure, the vibration fault types are summarized using vibration analysis method. It puts forward a series of solutions for the reciprocating compressors vibration faults sample of Pinghu platform and provides a sample of corrective measure for maintenance and operation of the same type equipment. It also proposes an improvement direction for future offshore platform compressor engineering design, skid, installation and operation. Related Articles | Metrics

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Dynamic Characteristics Analysis of Vibration Isolation Hanging with Advanced Friction Model LV Shun-ri;HUA Hong-xing 2012, 32(4): 169-172.  DOI: 10.3969/j.issn.1006-1355.2012.04.038 Abstract ( )   n order to investigate hanger’s characters of auto-adaptation vibration isolation, it was used the promoted Stribeck friction model in which the effects of both pressure and relative velocity to the glide friction force influence were concerned. According to the improvement of the friction model frame structure design, Runge-Kutta numerical method was used to calculate the hanger free response, forced response and the shock response. Results indicate that the excitation of the hanger in cosine, both for high amplitude (30 mm) low frequency [ω=0.1 ωn→ωn]and low amplitude (5 mm) [ω=1.4 ωn→6 ωn] hase good isolation. Also, it indicates that the system has a certain amount of resistance to shock. Related Articles | Metrics

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Design Analysis and Experimental Research of Rotor Fluidelastic Dampers WU Shen;YANG Wei-dong 2012, 32(4): 173-177.  DOI: 10.3969/j.issn.1006-1355.2012.04.039 Abstract ( )   Based on the helicopter rotor fluid damper work principle, elastic stiffness and loss coefficient expression were deduced. According to the parameters of rotor model the structure of liquid elastic damper was designed to meet the requirements, and fluid dynamics of elastic damper was tested for verification. Results show that the capacity of energy dissipation and dynamic characteristics of fluidelastic damper are better than that of elastomeric damper. Meanwhile, the consistency between tests and calculation results can ensure the validity and rationality of the theory and method which have been used in the design. The present study offers theory method to engineer helicopter rotor fluidelastic dampers. Related Articles | Metrics

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Performance Analysis and Experimental Verification of GWF Vibration Isolator LUO Hao;CHEN Jian-song;YAN Xiao-long 2012, 32(4): 178-182.  DOI: 10.3969/j.issn.1006-1355-2012.04.040 Abstract ( )   Resonance-free vibration isolator of model GWF dissipates vibrating energy by means of Coulomb-damping and elastic deformation, and it is widely used in vibration isolation for electronic equipment due to no harmonic peaks. Based on analysis of theoretical model, the unlock frequency and vibration isolation transmissibility for the GWF vibration isolator were obtained, the correctness of the theory was verified and an experimental and theory basis for selecting appropriate stiffness and friction force were provided. Related Articles | Metrics

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Application of μ MOGA in Damping Optimum Design of the Controllable Damper JIANG Chang-song;LI You-de;LI Jing 2012, 32(4): 183-187.  DOI: 10.3969/j.issn.1006-1355.2012.04.041 Abstract ( )   bstract : The μ multi-objective genetic algorithm is used to optimize the damping values of the controllable vibration damper. The damping parameters of the front and rear suspension are selected as the optimization variables, and the MSR values of the body vibration acceleration, the suspension travel movement and the tyres dynamic displacement are selected as the optimization objective. The three-levels damping values of the controllable vibration damper are optimized design by considering the characteristics of the different load, speed and road surface level for the suspension system at the same time. According to the optimization results, the three-levels damping values of the controllable vibration damper are confirmed, i.e. "soft-middle-hard". The suspensions simulation test proved that this algorithm is a kind of high efficiency of the multi-objective global optimization method. Related Articles | Metrics

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Analysis and Simulation of Vibration Energy Harvesting Behaviors of Triangular Piezoelectric Cantilevers QIAN Su-xiang;ZHU Ding-kun;HU Hong-sheng 2012, 32(4): 188-191.  DOI: 10.3969/j.issn.1006-1355.2012.04.042 Abstract ( )   he geometry of a piezoelectric cantilever beam will greatly affect its vibration energy harvesting ability. In the same volume of piezoelectric materials, the triangular piezoelectric vibrators have more power generation capacity, comparing with the rectangular and trapezoidal piezoelectric vibrators. Selecting a triangular cantilever piezoelectric vibrator as objective, the static and modal analysis were carried out using ANSYS code. The influence of piezoelectric vibrator geometry shape to its output voltage and the natural frequency was studied. Then in keeping the original output voltage, the optimization design of geometry size was carried to enhance the unit volume power capacity. The results show that, in the same boundary conditions and external force, the volume of the optimization size is 0.94 times of the original size, the output voltage of the optimization size is 1.03 times of the original size, and the optimization has a good effect. Related Articles | Metrics

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Longitudinal Resonance Method for Measuring Mechanical Parameters of Viscoelastic Materials ZHAO Jing;HOU Hong;SUN Liang 2012, 32(4): 192-194.  Abstract ( )   ased on virtual instrument measuring system, mechanical parameters of the viscoelastic material are measured in longitudinal vibration. One end of the bar is excited by a periodic sinusoidal signal with vibrator, while the other end is allowed to move freely. After which, the amount of acceleration of these two ends are measured using the transducer. At resonant frequency, Young's modulus and loss factor can be calculated using the amplitude of acceleration ratio between the driven end and the free end. Besides this, the sampled signals are averaged in several times, which can improve SNR highly. The measuring results agree well with that of commercial viscoelastic instrument. Related Articles | Metrics

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Noise Analysis and Discussion on Control Technique of Gas-steam Combined-cycle Power Plant LIANG Chang-De;MAO Rui-Yong;GONG Feng-Hai;OU Yan 2012, 32(4): 199-205.  DOI: 10.3969/j.issn.1006-1355.2012.04.045 Abstract ( )   ccording to domestic natural gas as fuel for gas - steam combined-cycle thermal power plant characteristic, it was known that the steam turbine engine, gas turbine, waste heat boiler, mechanical ventilation cooling tower, transformer, natural gas and other areas, as well as the circulating water pump room, water plant and other auxiliary equipment room are the main noise radiation zone. The analysis on these region acoustic source equipment and the acoustic source characteristic was carried out simultaneously. Specific control measures to the key source of regional noise were put forward Related Articles | Metrics

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Vibration Prediction Method and Computer Simulations on the Air Compressor ZHOU Yi;WANG Hai-jun;JIN Hai-shui 2012, 32(4): 206-209.  DOI: 10.3969/j.issn.1006-1335.2012.04.046 Abstract ( )   According to the base frequency vibration of the rolling piston air conditioning compressor, the vibrating system mechanical model of compressor was established. By use of numerical calculation, a certain type of compressor vibration acceleration forecast was obtained with higher precision. The vibration system computer simulation model of compressor was built. The air conditioning compressor and its piping system vibration were predicted. This result was useful to the prediction and simulation of compressor, air conditioning system design and pipe optimization design. Related Articles | Metrics