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18 February 2012, Volume 32 Issue 1 Previous Issue    Next Issue
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1.综述
2.振动理论与数值解法
3.运载工具振动与噪声
4.环境振动与环境声学
6.信号处理与故障诊断
7.减振降噪设备和器材
9.振动噪声测试技术


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1.综述

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Overview of the Research of Noise of Air Supply System in Fuel Cell Cars KANG Qiang;ZUO Shu-guang 2012, 32(1): 1-06.  DOI: 10.3969/j.issn.1006-1355-2012.01.001 Abstract ( )   The research status of the overall noise of fuel cell cars is introduced. It is indicated that the air supply system is the main noise source of fuel cell cars. Then, the research status of noise of the air supply system and the air compressor is introduced. In addition, the noise spectral characteristic of the air supply system in a fuel cell car is presented. Finally, the research concentration of the noise of air supply systems in fuel cell cars is summarized. Related Articles | Metrics

2.振动理论与数值解法

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Anti-shock Analysis of Rotating Propulsion Shafting of Warship LI Zeng-guang;ZOU Chun-ping 2012, 32(1): 7-12.  DOI: 10.3969/j.issn.1006-1355-2012.01.002 Abstract ( )   The anti-shock performance of the propulsion shafting is one of the decisive factors for the survival of warships. In this paper, the rotating propulsion shafting is treated as a low-speed rotor dynamic system. Based on the rotor dynamics theory, a finite element model of the rotating propulsion shafting is developed for analyzing its dynamic response under shock load. The differential equation of the presented model is solved by using the Newmark method. The characteristic of the dynamic response of the propulsion shafting under lateral shock load and the effects of rotation speed on the response is investigated through numerical simulations. It is found that the gyroscopic effect of the rotating shafting makes the bending vibrations in horizontal and vertical direction coupled, and the gyroscopic effect can be equivalent to a system’s damping effect. It is found that when the damping of shafting is smaller, the gyroscopic effect on the dynamic response is relatively larger. The maximum shafting deflection under lateral shock occurs at the middle of a segment of the shaft between two neighbouring bearings with larger spacing. Since the bending deflection of the shaft can absorb the shock energy effectively, the acceleration of propeller is greatly attenuated. Related Articles | Metrics

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Application of Statistical Energy Analysis Method in Prediction of Dynamics Response of Space Payload LIN Wei;Lü Cong-min;REN Wei-jia;WANG An-ping 2012, 32(1): 13-17.  DOI: 10.3969/j.issn.1006-1355-2012.01.003 Abstract ( )   Base on the characteristic of space payload, the dynamics response of the space payload is predicted by the statistical energy analysis method. By establishing the SEA model and analyzing the dynamics response of structure and key units, The simulation results are compared with test results, which showing the statistical energy analysis method is suitable for analyzing dynamics response of space payload, computational accuracy can meet the engineering requirements. Related Articles | Metrics

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Study on Modeling and Control Design of Hybrid Vibration Isolation System with Flexible Base WAN Hai-bo;LOU Jing-jun;ZHU Shi-jian;YAN Zheng-tao 2012, 32(1): 18-22.  DOI: 10.3969/j.issn.1006-1355-2012.01.004 Abstract ( )   An actual hybrid vibration isolation system usually consists of a rigid vibration source, a flexible base, an isolator and an actuator. It is a complex rigid-flexible coupled system with infinite dimensions. To obtain an accurate model and design the controller expediently, the hybrid vibration isolation system with flexible base is modeled based on the substructure modal synthesis method. The availability of this modeling method is proved in comparison with the FEM model built by ANSYS. Then, a hybrid vibration isolation control system is designed, simulated and analyzed based on the modified independent-modal space-control method. The results show that the vibration of the base is reduced effectively by the hybrid vibration isolation system, and the isolation effect is better than that of the passive vibration isolation system. Related Articles | Metrics

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Finite Element Analysis of a Pipe Structure with Perforated Damping ZHOU Ming-gang;RUAN Xiao-hui;HUANG Tao;ZHOU Xiao-qiang;CHEN Yuan 2012, 32(1): 23-25.  DOI: 10.3969/j.issn.1006-1355-2012.01.005 Abstract ( )   A perforated damping structure is put forward for vibration reduction of pipes of the structure. The vibration performance of this structure is analyzed in use of the modal strain energy method. The approximate dynamics calculation of elastic-viscoelastic composite structure is achieved by using FEM software ANSYS and APDL language programming. This method can be used to design and analyze viscoelastic damping structures in engineering practice simply and feasibly. The perforated damping structure presented in this paper is analyzed by means of this method and some useful conclusions are drawn which can be used as a reference for vibration and noise control of fluid filled pipes. Related Articles | Metrics

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Analysis of Single Pile’s Vibration in Layered Liquefied Soil YANG Wen-ling;YU Huan-xin;YUAN Yu-qing 2012, 32(1): 26-28.  DOI: 10.3969/j.issn.1006-1355-2012.01.006 Abstract ( )   The theory of vibration of pile foundation in layered soil is applied to the analysis of vibration of a single pile in liquefied soil. The dynamic interaction between pile and soil is described by Winkler spring-damper model. The amplification factor of the displacement at pile’s head under earthquake excitation is obtained by initial parametric method and transfer matrix method, in which the liquefied phenomenon of soil is considered. The result indicates that the softening coefficient, thicknesses of soil layers, flexural stiffness and mass density per unit length of the pile have great influence on amplification factor of the displacement at pile’s head. Related Articles | Metrics

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Study on Reverse Deduction of Two Material Parameters in Mooney- Revlin Model of Rubber Isolator LOU Jing-junZHU Shi-jianTANG Si-mi 2012, 32(1): 29-33.  DOI: 10.3969/j.issn.1006-1355-2012.01.007 Abstract ( )   The parameters of rubber model is usually obtained through a series of test of standard specimen. In the case of absent of standard specimen, it is significant in engineering application to reversely deduce the parameters of the material model with a few of information of the rubber isolator. In this paper, a new reverse deduction method based on the two material parameters in Mooney-Revlin model is proposed, with the consideration of the relationship between the two parameters C1 and C2, and hardness, and of the effect of C1 and C2 on the static characteristics of the rubber isolator. The MATLAB and ANSYS codes are applied to forecast the parameters. First of all, the value of C1+C2 is calculated under the condition of small displacement, and then the value of C2/C1 is obtained under the condition of large displacement. The material’s property of the rubber isolator is inversely designed. In order to verify the effectiveness of this method, the finite element model of a kind of rubber isolators is built, and the parameters are calculated based on the static compression characteristics. The effectiveness of the reverse deduction method is validated. Related Articles | Metrics

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Experimental Modal Analysis of Rubber Stern Bearing JIN Yong;;TIAN Yu-zhong;LIU Zheng-lin 2012, 32(1): 34-38.  DOI: 10.3969/j.issn.1006-1355-2012.01.008 Abstract ( )   Since rubber stern bearing has excellent shock absorption and noise reduction performances, it has been applied more and more in navel vessels. Using LMS platform and hammering method, the experimental modal analysis of the whole rubber stern bearing was carried out. The validity of the results was verified by MAC. It is shown that the range of intrinsic frequencies of the bearing from experimental modal analysis is in accordance with that calculated by ANSYS. However, because of the nonlinearity of rubber, the vibration modes of the rubber bearing have some differences from the computation results of ANSYS, while results of frequencies and vibration modes of the metal bush are in good agreement with those from the ANSYS computation. Related Articles | Metrics

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Modal Analysis and Model Updating of Optical Element SHAO Jun;YE Jing-feng;HU Zhi-yun;ZHANG Zhen-rong;HUANG Mei-sheng 2012, 32(1): 39-42.  DOI: 10.3969/j.issn.1006-1355-2012.01.009 Abstract ( )   To study the dynamic performance of optical elements, the modal experiment for an optical mirror mount was carried out as an example. Its dynamic computation model was established and its reliability was verified. And the modal analysis was done. To reduce the deviation between the theoretical model and practical situation, the dynamic computation model was updated from time to time by analyzing the relative sensitivity of the frequency to the model parameters such as material property, Poisson ratio, elastic modulus, geometrical dimensions and so on. Then the most sensitive parameter was found, and the model was updated according to this parameter. It is found that the dynamic characteristics of the updated model is closer to the measurement data, and the frequency deviation between the simulation and measurement is obviously reduced. Results show that the dynamic computation model is capable for describing the dynamic characteristics of the optical elements. Related Articles | Metrics

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Stochastic Optimal Control of Spherically Symmetric Piezoelectric Shells ZHANG Wei;SUN Yin;YING Zu-guang;FENG Ju 2012, 32(1): 43-46.  DOI: 10.3969/j.issn.1006-1355-2012.01.010 Abstract ( )   The stochastic optimal control of a spherically symmetric piezoelectric shell under random boundary excitations is studied. The dynamic equilibrium equation, the kinetic equation, the charge conservative equation and the electrical and mechanical coupling constitutive equations of the piezoelectric shell are given. These equations and the performance parameters construct a stochastic optimal control problem. The electric potential integral is presented to convert the governing equations into a mechanical vibration equation. Using the displacement transformation and the Galerkin method, the partial differential vibration equation is converted into ordinary differential equations for optimal control. Based on the stochastic dynamical programming principle, the HJB equation is derived and then the optimal control electric potential for the piezoelectric shell is determined. The frequency-response function, response power spectrum density and correlation function matrices of the controlled shell system are presented for estimating the random response. Finally, numerical results are given to demonstrate the effectiveness of the stochastic optimal control of the piezoelectric shell. Related Articles | Metrics

3.运载工具振动与噪声

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Application of Synthetic Modal Testing Technique in Noise and Vibration Reduction of White Body Components CHEN Yuan;ZHOU Xiao-qiang;ZHOU Ming-gang;HUANG Tao;ZHOU Jing-dong;RUAN Xiao-hui 2012, 32(1): 47-50.  DOI: 10.3969/j.issn.1006-1355-2012.01.011 Abstract ( )   The basic idea of the synthetic modal test is to divide the whole structure into several substructures. The modal parameters of the substructures are obtained by means of the modal test for the substructures, and then the parameters are synthesized and the whole structure modal parameters are gained. In automobile NVH analysis, the cost and time-consuming of the modal test for whole white body are usually very high. Using the synthetic modal test method, the cost and time-consuming of the modal test can be reduced, and the precision of the test can still satisfy the engineering requirement. Related Articles | Metrics

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Measurement and Analysis of Influence of Steel Spring Floating Slab Track on Vehicle Interior Noise XIAO An-xin;TIAN Ye 2012, 32(1): 51-54.  DOI: 10.3969/j.issn.1006-1355-2012.01.012 Abstract ( )   When a train passes through on steel spring floating slab, intermediate and low frequency noises will be generated in its vehicles. Such noises will reduce the traveling comfort. In this paper, the vehicle’s interior noises of floating slab in different tracks are compared and analyzed. The influence of steel spring floating slab track on vehicle’s interior noise is analyzed. The results show that the floating slab track with high damping steel spring can effectively reduce the interior noise. Related Articles | Metrics

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Simulation of Lateral Vibration of Urban Rail Vehicle Body CHANG Qing-bin;ZUO Yan-yan;YANG Jian 2012, 32(1): 55-58.  DOI: 10.3969/j.issn.1006-1355-2012.01.013 Abstract ( )   The influence of track irregularity on vehicle body’s lateral vibration is studied, and the performance of vehicle body’s vibration is evaluated. At first, a simplified urban vehicle’s model is established. Then the track irregularity is described and the track power spectrum in space domain is transferred into the spectrum in time-frequency domain. The 3D model of the vehicle’s body is established with PROE software, and then the wheel-rail model and the train’s simulation model are established with the use of the dynamic simulation software SIMPACK. Finally, with the height irregularity as excitation function, the lateral vibration response of the vehicle’s body is computed. Referring to the domestic standard of lateral stability, the lateral performance of vehicle’s body is evaluated. Related Articles | Metrics

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Noise Test and Analysis of 350 km/h High-speed Train with Different Distances DONG Hai-shan;HE Yu-long;YANG Li-zhong;DENG Jun 2012, 32(1): 59-61.  DOI: 10.3969/j.issn.1006-1355-2012.01.014 Abstract ( )   In order to investigate the noise level of different line forms of 350 km/h high-speed train, the noise intensity at different distance from the Beijing-Tianjin Inter-City high-speed railway was tested and analyzed. The result indicates that the noise level radiated by the train reaches the highest at 60m distance. Then the noise level decreases with the distance increasing. The result is significant for noise reduction design of the express train-sets. Related Articles | Metrics

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Optimum Study on Vibration Isolation Performance of Powertrain Mounting System ZHANG Yong;OU Jian;YANG E-Chuan 2012, 32(1): 62-66.  DOI: 10.3969/j.issn.1006-1355-2012.01.015 Abstract ( )   A multi-body dynamics model for analyzing power-train mounting system is established by adopting MSC ADAMS/View. The correctness of the model is verified by the measurement data of the vibration response of each component of the mounting system in idling condition. According to energy decoupling theory, the stiffness of each component of the mounting system is considered as the design variable, and the reasonable matching of natural frequency is taken as the restraint. Then, the best improvement of the energy decoupling of the power-train in the direction of stimulation is selected as optimization target to improve the vibration characteristics of an economic car in idling condition. The result shows that, considering stiffness as the design variable only can realize the improvement of decoupling property. To gain the complete decoupling, some other influencing factors should be taken into consideration. Related Articles | Metrics

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Analysis of Mechanical Mobility and Vibration Transfer Property in Powertrain - Vehicle’s Body System ZHANG Shou-yuan;ZHANG Yi-min 2012, 32(1): 67-71.  DOI: 10.3969/j.issn.1006-1355-2012.01.016 Abstract ( )   A simplified multiple DOFs lumped-parameter elements model is established to study the dynamic properties of vibration path in powertrain-vehicle’s system in high frequency range. The relationships among isolator, interface velocity and each component’s mobility are derived. The main parameters influencing the dynamic properties of the vibration paths are determined by component’s parameter study. Finally, effective methods are proposed to perform dynamic design of the powertrain-body vibration transfer system. Related Articles | Metrics

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Static Stiffness Calculation and Experimental Test of an Engine Mount for a Commercial Vehicle ZHANG Wei;SHANGGUAN Wen-bin 2012, 32(1): 72-76.  DOI: 10.3969/j.issn.1006-1355-2012.01.017 Abstract ( )   Three methods, including empirical formulas, finite element analysis and experimental test, are employed for studying a composite rubber mount of a commercial vehicle’s engine. Its three-dimensional static stiffness is obtained. Then relative errors of the three methods are analyzed and compared one another. The possible sources of the errors are given. However，the relative errors are found to be within the allowance (<15%) in engineering practice. Thus, as to this specific engine mount, the aforementioned methods for the three-dimensional static stiffness are acceptable and can shorten the cycle of product development. Related Articles | Metrics

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Subjective Vibration Evaluation and Modal Testing for the Overhead Guard of a Forklift Truck XU Chang;Yan Tian-hong;ZHANG Zhen 2012, 32(1): 77-80.  DOI: 10.3969/j.issn.1006-1355-2012.01.018 Abstract ( )   In this paper, the vibration of the overhead guard of a forklift is diagnosed. Firstly, the vibration signals are collected when the forklift is operating, and the signals corresponding to the worst subjective evaluation of comfort are extracted and analyzed. Then, the modal test of the overhead guard of the forklift is conducted, and the results are compared with the vibration signals corresponding to the worst comfort. It is found that the main reason of the forklift vibration which leads to the worst comfort is the resonance of the overhead guard excited by the engine. Since the modals of the overhead guard structure in the vicinity of the resonance frequency are very close one another, successive resonance will occur in the acceleration period, which is a serious impact on the comfort of the forklift. Finally, a scheme for reducing the vibration is proposed. A correlation between objective measurements and subjective evaluation is found by means of the proposed approach. This work supplies references for the vibration isolation design. Related Articles | Metrics

4.环境振动与环境声学

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Primary Quantification of Soundscape Elements in Urban Parks MA Hui;WANG Dan-dan 2012, 32(1): 81-85.  DOI: 10.3969/j.issn.1006-1355-2012.01.019 Abstract ( )   In the present work, the soundscape elements in three kinds of urban parks (coastal park, street park and general park) are studied. Wave sound, road traffic noise and water-flowing sound were considered as background sounds of these three kinds of parks respectively. Primary quantification of seven sounds including the wind sound, traffic noise, and birdsong and so on was analyzed in the scenes of the three kinds of parks with and without background sounds. According to the experiment results of subjective evaluation on soundscape elements and their sound levels, it is shown that people prefer natural sounds such as birdsong and sound of flowing water rather than artificial sounds such as the sound of broadcasting and traffic noise. Birdsong is considered as the most delightful and harmonious sound in all parks. Finally, the suitable sound level of each soundscape element was explored and the relationship between sound level and subjective evaluation was determined primarily. Related Articles | Metrics

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Research of Noise Contour Plotting of Steeper Approaches FEI Dai-xiang .YAN Guo-hua .BAO Hai-bing .CHEN Tuo 2012, 32(1): 86-88.  DOI: 10.3969/j.issn.1006-1355-2012.01.020 Abstract ( )   With the development of civil aviation industry, the influence of noise around airports has been becoming a serious problem. Since there is a lot of works on noise reduction of noise source, this paper will mainly pay attention to the steeper (6 degrees) approach noise reduction procedures. Since the INM software is not suitable for plotting steeper approach contour, each noise value in the Z-axis in three-dimensional coordinates is converted to an equivalent height. Then, the Surfer 8.0 software, the meteorology software with powerful functions, is adopted to plot the steeper approach contour and the three-dimensional surface map of noise level, so as to evaluate the noise influence of steeper approach on Cherry Park area near the Capital Airport. This work may be helpful for environmental noise control around the airports. Related Articles | Metrics

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Vortex and Noise Characteristics Analysis of the Flow-field Between the Two Impellers of a Contra-rotating Axial Fan CHEN Qing-guang;FANG Fei;ZHANG Yong-chao;J IA Xiang-xing 2012, 32(1): 89-92.  DOI: 10.3969/j.issn.1006-1355-2012.01.021 Abstract ( )   The LES technique was used to simulate the 3-D unsteady full flow-field of a contra-rotating axial fan. Several monitoring faces were arranged in the flow-field between the two impellers. The monitoring points were arranged in each monitoring face. The FW-H technique was used to simulate the aerodynamic noise of the flow-field between the two impellers. The contours of vorticity magnitude of the monitoring faces and the sound pressure levels of the monitoring points were processed. The vortex and the aerodynamic noise characteristics in the monitoring faces were analyzed. This study may be useful for the analysis of fan’s aerodynamic noise. Related Articles | Metrics

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Influence Factors and Control Countermeasures of Traffic Noise Based on Grey Relational Analysis LI Hui;;PENG Xiao-chun;ZHONG Zhi-qiang;BAI Zhong-yan;HONG Hong-jia 2012, 32(1): 93-95.  DOI: 10.3969/j.issn.1006-1355-2012.01.022 Abstract ( )   Traffic noise pollution has become one of the serious environmental pollution problems in modern city. Taking a city in south China as an example, the relationship between traffic noise and its influence factors is analyzed by using grey relational analysis, and the main influence factors of traffic noise are found. The measures for controlling the urban traffic noise are put forward. Related Articles | Metrics

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Overview of Domestic and European Sound Insulation Standards for Civil Building LI Ming-bin;LU Feng-hua 2012, 32(1): 96-98.  DOI: 10.3969/j.issn.1006-1355-2012.01.023 Abstract ( )   Noise pollution has become one of the serious problems in our daily life. The standard for design of sound insulation for civil buildings is of important significance for people to have a comfortable acoustic environment. In this paper, a new domestic standard for sound insulation design of civil buildings is analyzed and compared with the standards of some European countries. This overview may provide some help for implementation of the new standard. Related Articles | Metrics

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Dynamic Modeling and Feature Analysis of Traffic Noise in Elevated Road ZOU Jing-Fang 2012, 32(1): 99-104.  DOI: 10.3969/j.issn.1006-1355-2012.01.024 Abstract ( )   This paper models the dynamic traffic noise in elevated road and analyzes the impact of traffic noise on nearby buildings under various conditions. Combining microscopic traffic flow simulation technique, vehicle noise emission levels and noise propagation attenuation principle, the dynamic traffic noise simulation model for elevated road is established. And the instantaneous equivalent sound level and statistical sound level are calculated. The vertical and horizontal acoustic fields of the elevated road are simulated. The impacts of multi-lanes, vehicle speed, traffic volume, height of sound barrier and tree belt on the traffic noise level of the elevated road are analyzed. Also, the impact of traffic noise on different floors of buildings along the elevated road is analyzed. This work may provide a reference for traffic control, speed-limiting, sound barrier constructing and tree belt planning. Related Articles | Metrics

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Analysis of Noise Control of an Urban 110 kV Indoor Substation LI Ming;CHEN Jin-dong 2012, 32(1): 105-108.  DOI: 10.3969/j.issn.1006-1355-2012.01.025 Abstract ( )   The characteristics of an urban 110kV indoor substation and its noise are described. Its noise control methods are briefly analyzed. An example of noise control of a typical urban 110 kV indoor substation—Shanghai Anshan 110 kV substation, is introduced. It can be used as a reference for similar projects. Related Articles | Metrics

6.信号处理与故障诊断

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Evaluation of Sound Quality of Gear Noise Based on Psychoacoustic Parameters TIAN Rui 2012, 32(1): 109-112.  DOI: 10.3969/j.issn.1006-1355-2012.01.026 Abstract ( )   Currently, most gear plants use noise sound-level-meter to determine whether their gear products satisfy the noise standard or not. However, some automotive companies complain that some qualified products of gears are still very noisy. It implies that the parameters for noise evaluation may be unreasonable. In this paper, a car’s rear axle gear produced by a gear plant in Guangdong province is taken as the noise source, and the noise of the gear in steady-state operation is collected for study. The grade evaluation method and the professional software Artemis for sound quality evaluation are employed for subjective and objective evaluation of the noise. It is suggested that the sound pressure level and loudness should be the main indexes for noise evaluation of the rear axle gear of mini-cars. The model for sound quality evaluation of gear’s noise is established. Finally, by making software, the objective calculation and analysis of the weighted sound pressure level and loudness are realized. Related Articles | Metrics

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Statistical Feature of Hilbert - Huang Transform and Its Application in Aeroengine Vibration Analysis WU Ya-hui;LI Xin-liang;HONG Bao-ling;ZHANG Da-zhi 2012, 32(1): 113-118.  DOI: 10.3969/j.issn.1006-1355-2012.01.027 Abstract ( )   The vibration signals of the aeroengine include many multi-frequency components and noise components. In this paper, the Hilbert-Huang transform is used to decompose the vibration signals into a number of intrinsic mode functions (IMF) which represent different physical meanings of the data. Then, the generalized roughness vector of the IMF weighted by its energy is extracted from the IMF signals. Finally, as the fault characteristic vectors, the derived parameters are input into the support vector machine (SVM) classifier and the working conditions and fault patterns are identified by the output of the classifier. Results from the analysis of aeroengine vibration signals show that this fault diagnosis method can classify the working conditions and the fault patterns effectively. Related Articles | Metrics

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Simulation and Experimental Study on Damage Detection in Welded Rectangular Tube Based on Guided Wave LU Xi;;ZHOU Li-min;MENG Guang 2012, 32(1): 119-123.  DOI: 10.3969/j.issn.1006-1355-2012.01.028 Abstract ( )   Guided wave based detection methods have become a hot area of research in structural health monitoring (SHM), and have a great potential in engineering applications. A welded tubular component, which is a segment of train bogie frame, was investigated by using both finite element method (FEM) and experimental analysis for the purpose of damage detection. 3D FEM models were established to simulate the propagation characteristics of guided waves in the component. An active transducer network was employed to generate guided waves propagating in the structures and to collect response signals. Excitation frequency was carefully optimized to diminish the effect of the intrinsic multi-mode phenomenon of guided waves on the consequent signal interpretation. Continuous wavelet transform (CWT) and Hilbert transform (HT) were applied to all collected signals successively. Guided wave-based triangulation was developed and consequently utilized in damage location estimation. Effectiveness of the recommended approach was validated in experiments. Related Articles | Metrics

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Detection and Analysis of Aeroengine Rotor-stator Rubbing Trouble using Wavelet Analysis FU Rao;ZHANG Qun-yan;ZHAO Shu-yuan 2012, 32(1): 124-127.  DOI: 10.3969/j.issn.1006-1355-2012.01.029 Abstract ( )   The rotor-stator rubbing signals of aeroengines in flight test are processed and analyzed. Firstly the original signal is denoised by wavelet threshold method so that the high-frequency noise is filtered and the saltatory information including important fault characteristics is reserved. Then the denoised signal is processed by continuous wavelet transform. The result from time-frequency analysis shows that it has a strong capability to track the rotor frequency in real-time. Furthermore, the energy of the frequency band is centralized and the fault features are obvious. So this method provides an effective approach for real-time fault monitoring of rotor-stator rubbing with the actual flight loads on. Related Articles | Metrics

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Comparative Simulation Study of Evolutional Wavelet Based on Denoising Algorithms WANG Shuan-zhong;ZHU Yu-tian 2012, 32(1): 128-132.  DOI: 10.3969/j.issn.1006-1355-2012.01.030 Abstract ( )   A comparative simulation study of various evolutional wavelet based denoising algorithms is presented. The soft denoising method, hard denoising method and various evolutional wavelet-threshold denoising functions are analyzed, and the necessary conditions of conducting evolutional wavelet-threshold denoising algorithms and a new function for this method are proposed. Meanwhile, all of these denoising functions are tested in a simulation experiment through four typical input signals contaminated by the Gaussian white noise, and these methods are evaluated according to some standards. Finally, the characteristics of the evolutional wavelet-threshold based denoising algorithms are summarized. Related Articles | Metrics

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Weak Fault Signal Extrction and Identification Based on DCT CHEN Yan-long;ZHANG Pei-lin;WU Ding-hai;WANG Huai-guang 2012, 32(1): 133-136.  DOI: 10.3969/j.issn.1006-1355-2012.01.031 Abstract ( )   Weak signal extraction is a traditional difficulty in fault diagnosis. In this paper, a new method based on discrete cosine transform (DCT) is introduced. In this method, the original time series is transferred to a corresponding coefficient vector, then the signal is reconstructed and the weak fault information is extracted. This method is compared with the wavelet noise-reduction method. In the simulation of an example, the weak fault components in mixed signals were strongly reappeared and the information of the weak fault signal was extracted efficiently from the strong powerful background noise. This method is less computer-time consuming. The process is easy to realize. It provides an efficient approach for real time monitoring. Related Articles | Metrics

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Ultrasonic Detection of Lamb Wave Stimulation and Modal Analysis of Thin Steel Plate Structure AI Chun-an;WANG Xue-yong;LIU Yu 2012, 32(1): 137-140.  DOI: 10.3969/j.issn.1006-1355-2012.01.032 Abstract ( )   This paper studies a common method and its procedure of ultrasonic detection of Lamb wave stimulation in thin steel plate structure. The signal was stimulated by ultrasonic oblique incident Lamb wave and the modes of the signal were analyzed. According to the experiment, it is found that with a proper combination of frequency and incident angle, selection and control of the modes of the Lamb wave can be realized. Thus, the best stimulating strategy of the detection can be obtained. This study is of important significance for the Lamb wave testing in engineering application. Related Articles | Metrics

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Time-frequency Analysis of the Characteristic of Vibration Signal of the Engine with One Cylinder Flaming out WANG Zi-xuan;CHEN Da-ming 2012, 32(1): 141-144.  DOI: 10.3969/j.issn.1006-1355-2012.01.033 Abstract ( )   The vertical vibration signal of engine block is analyzed in time and frequency domains based on the reassigned smoothed pseudo Wigner-Ville distribution (RSPWVD) when one engine cylinder faces flameout. When the engine accelerates from 0 to 1200 r/min, the vibration signals have different characteristics in normal working condition from those in the condition that one cylinder flames out. The variation of frequencies for the signals with time in these two conditions are extracted and analyzed using the RSPWVD of time-frequency analysis. The results show that RSPWVD can give a clear description in time and frequency domains for the signals. Therefore, a method based on time-frequency analysis is provided for the diagnosis of one cylinder’s flameout. Related Articles | Metrics

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Development and Experimental Verification of Shaft Vibration Monitoring System WANG Wei-Ci;Yan Zhou;Zhu-Shi Rao 2012, 32(1): 145-148.  DOI: 10.3969/j.issn.1006-1355-2012.01.034 Abstract ( )   With the use of ARM and DSP as the platform, a set of comprehensive on-line vibration monitoring system for marine power shaft system was developed for assuring its operation safety. The electric strain measurement, wireless telemetry and digital signal processing techniques were applied. The real-time monitoring of the operation status of the shaft system can be realized with this system. Some important parameters can be obtained on time so that the operation safety of the shaft system can be guaranteed. The monitoring system was verified by the testing on a diesel engine testing bench. Results of measurement showed that the shaft vibration monitoring system could achieve higher accuracy in monitoring. Related Articles | Metrics

7.减振降噪设备和器材

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Study on Transverse Impact Characteristics of Flexible Rubber Pipe Joint SHAO You-hua;ZHANG Zhen-hua 2012, 32(1): 149-153.  DOI: 10.3969/j.issn.1006-1355-2012.01.035 Abstract ( )   The transverse impact characteristics of a flexible rubber pipe joint are studied. A pair of joints assembled end-to-end with an inserted middle mass was tested in a drop shock testing machine. Based on the test results, an equivalent beam model with fixed-ends and polynomial varying stiffness and damping was applied to predict the transverse impact response and identify the nonlinear impact parameters. The least square residual between the computed and tested results was chosen as the target to perform the identification optimization. The results show that the equivalent bending stiffness of the flexible rubber pipe joint gradually decreases with the increasing of the transverse deformation and is greatly influenced by its internal working pressure. Related Articles | Metrics

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Study on Vibration Isolation Performance of Polyurethane Elastomer XIE Hua;WU Heng-liang;CHE Zhen-dong 2012, 32(1): 154-156.  DOI: 10.3969/j.issn.1006-1355-2012.01.036 Abstract ( )   Casting polyurethane elastomers were synthesized from TDI and MDI by prepolymerizing. The effects of different chain extender and the content of -NCO group in prepolymer on the mechanical properties were analyzed. Compared with rubber isolator, casting polyurethane isolator has lower nature frequency, better dynamic performance and higher loading capacity. Fatigue test results showed that the polyurethane isolator has excellent anti-fatigue performance. Related Articles | Metrics

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Study on the Effect of Active Control Actuator Components Made of Magnetic Shape Memory Alloy WENG Guan-gyuan;WANG She-liang 2012, 32(1): 157-162.  DOI: 10.3969/j.issn.1006-1355-2012.01.037 Abstract ( )   In order that the magnetic shape memory alloy (MSMA) can be more conveniently applied to civil engineering structure’s vibration control, the mechanical properties of MSMA are studied, and the output of the control force of MSMA is given. Active control components made of MSMA are developed independently. The shape and size of the MSMA materials in the actuator are determined. Deformation recovery device and magnetic circuit are designed. Model of the single-layer reticulated spherical shell structure of 80m diameter is established. Three schemes for arrangement of the MSMA intelligent control elements are designed and realized. The response spectrum is applied to calculate the response of these elements to vertical seismic excitation. Through the comparative analysis of the results with those of the response without control, it is found that the MSMA control is efficient, and the effect of MSMA active control elements is obviously good. Thus, MSMA is a kind of ideal intelligent drive materials, and has wide application prospects. Related Articles | Metrics

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Effect of Flexible Couplings on Response of a Vibration System SU Fang;MA Jian-min;LIU Ying 2012, 32(1): 163-166.  DOI: 10.3969/j.issn.1006-1355-2012.01.038 Abstract ( )   A vibration system with flexible couplings is taken as the subject to study. Dynamics equations of the system are established using Lagrange equation and solved numerically. Then, the effect of the flexible couplings on response of the vibration system in each stage is analyzed. In the initial stage, the response of the vibration system consists of three frequency components: the excitation frequency, the natural frequency of the vibration system and the natural frequency of the rotation system. In the steady state of vibration, the response of the vibration system only includes the excitation frequency of the system. In addition, the effect of flexible couplings on motion stability of the vibration system is analyzed. The response of rotation system due to the external disturbance is calculated. The results show that the effect of disturbance on the vibration system can be suppressed as the damping of the flexible coupling increases. Related Articles | Metrics

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Study on Polyurethane Isolators Subjected to High Loading WU Heng-liang;XIE Hua;CHE Zhen-dong 2012, 32(1): 167-169.  DOI: 10.3969/j.issn.1006-1355-2012.01.039 Abstract ( )   Casting polyurethane material has good dynamic performance. In this paper, through the testing of the polyurethane material specimen, and the testing and the numerical simulation of the vibration isolators made of this material, the allowable stress of the polyurethane material is determined. On this base, a polyurethane vibration isolator which is able to bear 300kN loading is developed, and its first intrinsic frequency is found to be lower than 5Hz. Related Articles | Metrics

9.振动噪声测试技术

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Environmental Vibration Test and Analysis of Viaduct Bridge of 350 km/h High-speed Railway HE Yu-long;ZHOU Qing;YANG Li-zhong 2012, 32(1): 170-173.  DOI: 10.3969/j.issn.1006-1355-2012.01.040 Abstract ( )   High-speed trains traveling at high velocities will generate ground vibration pollution, which is one of the main forms of environmental pollution. In order to investigate the environmental vibration level of viaduct bridges of high-speed railway, the environmental vibration is tested and analyzed for No.247 pier of the Yang Cun mega bridge of Beijing-Tianjin Inter-City high-speed railway when the train is traveling through. The result shows that the attenuation regularity of the maximum Z weighted vibration acceleration level VL zmax, the cumulative percent Z weighted vibration acceleration level VL z10, and the equivalent continuous Z weighted vibration acceleration level VL zeq all follow the Logarithmic law with increasing of the distance from the viaduct bridge to the measurement point. There is an obvious attenuation of environmental vibration within 30 m distance from the vibration source, and a smooth attenuation out of 30 m from the vibration source. The value of environmental vibration predicted by the current prediction formula of China’s high-speed train is 9.7 % higher than the measured value within 15 m to 60 m distance from the vibration source. Related Articles | Metrics

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Comparison of Sound Pressure Method and Sound Intensity Method in Application to the Measurement of Sound Insulation Preformance of Vehicle’s Body CHENG Zhi-wei;YE Zi-wen;LIU Wen;YE Zhi-gang 2012, 32(1): 174-176.  DOI: 10.3969/j.issn.1006-1355-2012.01.041 Abstract ( )   In this paper, two measurement methods, sound pressure method and sound intensity method, for the measurement of sound insulation performance of vehicle’s body are compared and discussed. It shows that the two methods have their own characteristics, and both of them play instructive role in improvement of sound insulation effect and noise reduction. Related Articles | Metrics

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Shock Testing Technique of Marine Diesel Power Plant WANG Zhi-gang;SHEN Jian-ping;MA Bing-jie 2012, 32(1): 177-179.  DOI: 10.3969/j.issn.1006-1355-2012.01.042 Abstract ( )   Anti-shock capacity of marine diesel power plant is very important for the survival of modern navy ships. Ship’s shock testing is an effective approach to study the anti-shock competence of the plant. In this article, the shock testing technique of marine diesel power plant is studied. The selection of test parameter, sensor installation, construction of test system and data processing of the diesel power plant are discussed. Finally, the shock testing method of marine diesel power plant is summarized. The result of this study can be applied to the shock test of some other marine equipment. Related Articles | Metrics