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Response of two-disk rotor with squeeze film dampers and optimization of supports 2013, 33(5): 1-3.  Abstract ( )   PDF (812KB) ( )   This paper investigated the dynamical response of a low pressure rotor in aero-engine and optimization of its supports. Based on the model of low pressure rotor, a dynamical simplified model of two-disk rotor with Squeeze Film Damper (SFD) at each end was built. Its motion equations were derived. The numerical method was applied to solve the 12-dimensions differential equations and obtain the responses of rotor. To decrease the vibration of the rotor, the stiffness of elastic supports of the rotor needed to be optimized. The Multi-Island Genetic Algorithm and Sequential Quadratic Programming were applied to realize the multi-objective optimization and the best stiffness of two supports was obtained. Related Articles | Metrics

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Bending and Torsional Coupled Vibration of a Propulsion Shafting System Excited by Friction Force 2013, 33(5): 4-9.  DOI: 10.3969/j.issn.1006-1335.2013.05.002 Abstract ( )   PDF (1388KB) ( )   Abstract: The load state of the stern bearing of the propulsion shafting system is affected by factors such as the propeller and the shafting alignment. Unreasonable design or installation of the shafting system will result in poor lubrication of the rubber bearing, which probably causes the stick-slip motion between the shaft and the bearing and abnormal bending and torsional vibration of the shafting system. In this paper, the bending and torsional vibration induced by the friction between the stern bearing and the propulsion shaft is analyzed thoeretically, revealing the characteristics of friction induced shaft vibration and noise. Related Articles | Metrics

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Analysis of Dynamic Characteristics of Fluid-structure Interaction in Fluid-filled Pipes 2013, 33(5): 10-14.  DOI: 10.3969/j.issn.1006-1335.2013.05.003 Abstract ( )   PDF (1100KB) ( )   The interaction between fluid and elastic solid in a fluid-filled pipe plays a key role in pipeline vibration. The fluid-structure coupling effect has a direct impact on the pipe dynamic characteristics. In this paper, using experiments and numerical analysis, a fluid-filled pipe system under the fluid-structure interaction is employed to study its dynamic characteristics, such as pipeline vibration modal, amplitude frequency response and so on. According to the coupling relationship of the three-dimensional fluid wave equations and structural dynamics equations, the 3D piping system is modeled as a fluid-solid coupling finite-element model, and the modal testing of the system is carried out considering two different cases, pipeline without water and with water. Comparing the numerical results with test data, the fluid-solid coupling dynamic model is validated and the effects of fluid on the pipeline modal are analyzed. The influence and mechanism of coupling characteristics on amplitude-frequency responses of the pipe system are investigated at different excited frequencies. It is found that the effects of water medium reduce remarkably pipe natural frequencies, but the effects of fluid on pipe amplitude frequency responses are variable at different frequency. Related Articles | Metrics

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Affect of Damping on Non-linear Vibration of Blades 2013, 33(5): 15-18.  DOI: 10.3969/j.issn.1006-1335.2013.05.004 Abstract ( )   PDF (1003KB) ( )   Simplified the turbine blade as a cantilever plate model. Considered the effect of damping and regarded the air resistance as harmonic load. Based on the Von-karman board control theory, established the control equation with forced vibration of sticky damping. Choosed a group of modal functions which meet the blade boundary conditions. Adopted the Galerkin method to discretize the equation and used Multi-scale method to solve. According to the results of the numerical method, compared with linear vibration, the pat phenomenon more thin in non-linear vibration. The non-linear frequency response curve shows the multi-value and jumping characteristic, and the damping parameter has influence on its shape. Related Articles | Metrics

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Fish Washbasin: Experiment of Hand-Basin-Water System and Analysis of Its Dynamic Characteristics 2013, 33(5): 19-25.  DOI: 10.3969/j.issn.1006-1335.2013.05.005 Abstract ( )   PDF (2012KB) ( )   This paper has carried on the detailed kinetic theory analysis and experimental study based on the Fish Washbasin water spray phenomenon. First, the Fish Washbasin were filled with water and anhydrous ears hanging experimental modal analysis, complete to get around the first eleven natural frequency, mode and damping ratio; secondly, the Journal of hand rubbing spraying experiment, through the operational modal analysis theory and algorithm, obtained the water state of the modal parameters, through and the experimental modal analysis and comparison of the results obtained by the fish water state, dynamic characteristics and modal parameters of a consistent conclusion; third, a vibrator resonance experiments, the known under the guidance of the use of modal frequency, vibration exciter on basin water system of fixed frequency steady state excitation, the modal frequency the resonance phenomenon under water, fish in the description of resonance excitation can spray water, and water spraying state kinetic parameters and modal parameters are consistent. Related Articles | Metrics

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Finite Element Modeling and Validating of   Structural Uncertainty Factors 2013, 33(5): 26-29.  DOI: 10.3969/j.issn.1006-1335.2013.05.006 Abstract ( )   PDF (1075KB) ( )   　　It is necessary to study the finite element (FE) modeling and validating in consideration of the uncertainty, because the assembled uncertainty is widely existent in the engineering structure. The hiberarchy of the test design and multi-case suppositional modal tests about an assembled beam structure are carried out. The identification, quantification of uncertain parameters and the model validation are performed via the model validation frame. The example study shows the course when modeling with the uncertainty, at the same time, the difference between the traditional certain FE modeling and that considering the uncertain is showed. All kinds of methods in the paper may be referenced??for other engineering structures similar study. Related Articles | Metrics

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Analysis for 1/3 Order Sub-harmonic Resonance of an Inclined Beam Subjected to Harmonic Excitation in Temperature Field LI Gao-Feng 2013, 33(5): 30-35.  DOI: 10.3969/j.issn.1006-1335.2013.05.007 Abstract ( )   PDF (1420KB) ( )   Based on nonlinear vibration equation of inclined beam subjected to harmonic excitation in temperature field, the first approximate solution of 1/3 subharmonic resonance of the nonlinear vibration system is obtained by means of the method of multiple scales for nonlinear oscillations. Numerical analysis on the influence of temperature, excitation, and geometric parameter on amplitude frequency response curve is as follow. With the increasing of initial temperature and amplitude of excitation, the amplitude and resonant region of the 1/3 subharmonic resonance increases. With the increasing of temperature coefficient and ratio of length to height, the amplitude and resonant region of the 1/3 subharmonic resonance decreases. Related Articles | Metrics

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Vibration Analysis of a Rotor-seal System Based on an Improved Seal Force Model 2013, 33(5): 36-40.  DOI: 10.3969/j.issn.1006-1335.2013.06.008 Abstract ( )   PDF (1276KB) ( )   A rotor-seal system is proposed based on Jeffcott rotor model and improved two-control volume model. Jeffcott rotor model is simplified and the state equation of the system can be obtained. The Two-control volume model is improved and the control equations of the system can be obtained according to the continuity and momentum equations. The vibration characteristics of the rotor-seal system are investigated by combining state equation with control equations together. The nonlinear phenomena of the rotor-seal system are investigated. Related Articles | Metrics

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Analysis Method of Structure-acoustic Coupled Systems 2013, 33(5): 41-44.  DOI: 10.3969/j.issn.1006-1335.2013.05.009 Abstract ( )   PDF (1431KB) ( )   An analysis of two-way coupled structural-acoustic systems has been presented in this paper. A particular solution approach in conjunction with the modal expansion method has been applied to solve such coupled systems. For this domain, numerical results of the mode shapes which show the dominance of acoustic and structural resonances have been presented. The ratio of the structural driving point impedance to the acoustic characteristic impedance has been studied in an effort to identify when the fully coupled structural-acoustic analysis is necessary. The change of structural resonant frequencies due to the coupling is studied as a function of the impedance ratio. It is found that the changes of structural resonant frequencies tend to peak near where the impedance ratio is unity. These changes can be used as a standard to decide when to use the two-way coupled analysis. Related Articles | Metrics

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Model Updating of the Baseplates of Satellites Based on DQPSO 2013, 33(5): 45-47.  DOI: 10.3969/j.issn.1006-1335.2013.05.010 Abstract ( )   PDF (919KB) ( )   The baseplate of the satellite is equivalent to a single-layer board to calculate its structural parameters, and the quantum particle swarm optimization algorithm(QPSO) is improved to add a dynamic factor, then the quantum particle swarm optimization algorithm with dynamic factor(DQPSO) is used to update the finite element model of the baseplate of the satellite, which is made of honeycomb sandwich plate. Return the update data to the MAC/NASTRAN to do another calculation and the result shows that the dynamic data calculated by the updated model can better match the test data, which proves the rationality of the equivalence and the availability of the algorithm. Related Articles | Metrics

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Noise Analysis and Control of Marine Oil Separator 2013, 33(5): 48-52.  DOI: 10.3969/j.issn.1006-1335.2013.05.011 Abstract ( )   PDF (1356KB) ( )   In this paper, the vibration and noise of marine oil separator is measured for its noise badly influenced practice teaching in marine engineering teaching laboratory. According to the results including modal character,dynamic spectrum,and the coherence between vibration and noise，effective methods are researched to control the noise and vibration of marine oil separator. Difference from the traditional way of changing the structures, vibration isolators and artificial damping are used in this paper to reduce the chamber noise. This research provides some suggestions for the vibration and noise control of marine oil separators and other equipments. Related Articles | Metrics

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Analysis of Aerodynamic and Vibration Characteristics of a Micro Quad-rotor Helicopter with Low Reynolds Number 2013, 33(5): 53-57.  DOI: 10.3969/j.issn.1006-1335.2013.05.012 Abstract ( )   PDF (1266KB) ( )   Abstract: Aerodynamic characteristics and vibration characteristics of a micro quad-rotor aircraft were studied based on finite element method. A three dimensional physical model of the fluid fields was established. By adding boundary conditions, the fluid fields were analyzed numerically using the finite volume method and the aerodynamic characteristics were obtained. Then the aerodynamic force was loaded to the aircraft structure to get the stress distribution and find out where the maximum stress is. At last, the first six vibration modes and their vibration characteristics were obtained after the modal analysis of the micro quad-rotor aircraft. Related Articles | Metrics

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Advances in Noise and Vibration Environment Prediction of High Speed Spacecrafts 2013, 33(5): 58-63.  DOI: 10.3969/j.issn.1006-1335.2013.05.013 Abstract ( )   PDF (709KB) ( )   Noise and vibration environment prediction technique of spacecraft is critical to spacecraft system design and structure design. In this paper, status and development of Noise and Vibration environment prediction technique is reviewed. By the authorial research practice in an engineering application and theory, main research directions is presented deals with source of the Noise and Vibration, Transmission Property of the noise and vibration, structural dynamic response analysis. Final, it is pointed out that research results in these directions will contribute to solving the problem of the noise and vibration environment prediction with full-frequency bands and whole flying trajectory Related Articles | Metrics

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Analysis of Exhaust Noise Contribution to Vehicle’s Interior Noise Based on Single Path Inversion 2013, 33(5): 64-66.  DOI: 10.3969/j.issn.1006-1335.2013.05.014 Abstract ( )   PDF (1021KB) ( )   The transfer path analysis from exhaust noise to vehicle interior noise is carried out based on exhaust volume acceleration estimated using single path inversion method. It can be found that exhaust noise is the main noise source for vehicle interior noise in the engine speed 1730rpm, and the reason of high sound pressure level of vehicle interior noise is related to the large volume acceleration, not the transfer path function from exhaust orifice to automotive interior noise. A test is performed to validate the reliability of the results by comparing the sound pressure level of driver’s right ear with and without the isolating the exhaust noise. Related Articles | Metrics

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Vibration Characteristics Analysis and Model Modification of an Aircraft in Thermal Environment 2013, 33(5): 67-71.  DOI: 10.3969/j.issn.1006-1335.2013.05.015 Abstract ( )   PDF (1229KB) ( )   In this paper, the finite element model of a aircraft with complex composite structures is constructed for dynamic simulation under thermal environment. Analysis of its dynamic characteristic is presented, based on which the FEM model is optimized according to the modes test done in ordinary temperature environment on earth. The vibration characteristics of the aircraft under ordinary temperature are obtained. Also obtained is the changing of the characteristics affected by the given thermal environment. Then the methods of constructing the FEM model of this kind of composite structures and optimizing the model using MSC.Nastran SOL200 are presented, which will be very useful for the project mission. Related Articles | Metrics

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Research on Prediction of Sound Insulation to Body Structure of High-Speed Train based on Hybrid FE-SEA Method 2013, 33(5): 72-76.  DOI: 10.3969/j.issn.1006-1335.2013.05.016 Abstract ( )   PDF (1078KB) ( )   In this paper, the hybrid FE-SEA method was used to predict sound insulation performance of body structure of high-speed train. Two different hybrid FE-SEA models based on reverberation chamber and DAF- SIF theories were built. Compared the simulation results, the sound insulation of two models predicted the same result, and the simulation results compared with the test values, it was shown that in the middle frequency range of 100Hz ~ 1000Hz , hybrid FE-SEA could predict sound insulation of body structure efficiently and rigorously. Related Articles | Metrics

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Handling and Stability Experiment of Active Suspension and EPS Integrated Control System 2013, 33(5): 77-81.  DOI: 10.3969/j.issn.1006-1335.2013.04.017 Abstract ( )   PDF (1839KB) ( )   According to the model and control strategy of the active suspension and EPS integrated control system, simulation and analyzing of the step input angle of the steering wheel angle were carried out. The simulation results showed that, the peak and standard deviation of roll angle and vehicle body pitch angle were decreased by a certain degree in comparison with the passive system. In order to verify anti-roll capability of the integrated control system, snaking road test was carried out at speed of 50km/h and 60km/h, experimental results showed that, the peak and standard deviation of lateral acceleration were decreased by 21.4% and 15.9% in comparison with the passive system, and the peak and standard deviation of roll angle were decreased by 13.4% and 15.1%, which means that vehicle controllability stability and driving safety were improved effectively while cornering. Related Articles | Metrics

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Test and Analysis of Inner Noise of Automobiles 2013, 33(5): 82-85.  DOI: 10.3969/j.issn.1006-1335.2013.05.018 Abstract ( )   PDF (1060KB) ( )   Test and analysis the noise of the different test points inside the car, research the distribution rule. The results show that the inner noise increase 4 dB (A) with the car’s speed increase 10 km/h. The noise between front seat and back seat has deviation, the frequency range is 125~200Hz and800~2000Hz. Wind noise can make deviation between left and right ears, the variation trend is become higher and then fall off with the speed’s increase. Sedan car’s inner noise of the back seat is better than the Hatchback car’s. These results are value of reference in noise control design of automobile. Related Articles | Metrics

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Frequency Characteristics of Noises of Various Types of Vehicles in Different Speeds 2013, 33(5): 86-89.  DOI: 10.3969/j.issn.1006-1335.2013.05.019 Abstract ( )   PDF (1100KB) ( )   This paper describes an investigation about the frequency characteristics of the various types of vehicles in different speed. The noise samples were recorded to analyze the spectrum and the energy ratio of different frequency bands. The results showed that most of the vehicle noise energy was mainly located between 400Hz and 2.5kHz. The noise energy distribution of small cars was almost from 1kHz to 2.5kHz, the noise energy of large cars was evenly distributed from 400Hz to 2.5kHz and the noise energy distribution of middle cars was in between. Most of buses noise energy was located in low-frequency band from 10Hz to 315Hz. As the speed increased, the energy distribution of small cars and middle cars was more concentrated, the noise frequency of large cars has no significant relationship with speed and the ratio of bus noise energy in low-frequency band was increased. Related Articles | Metrics

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Study on Flutter of Three-dimensional Model of    Wind Turbine Blades 2013, 33(5): 90-96.  DOI: 10.3969/j.issn.1006-1335.2013.05.020 Abstract ( )   PDF (1982KB) ( )   Related Articles | Metrics

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Cause Analysis of Wind-turbine Resonance 2013, 33(5): 97-101.  DOI: 10.3969/j.issn.1006-1335.2013.05.021 Abstract ( )   PDF (1248KB) ( )   For the vibration alarms occurred frequently at the generator speed of 1400 rpm when the wind turbine worked, this article made a vibration test for the wind turbine and found out that it occurs resonance. By analyzing the data and phenomenon, it found out that the reason for the resonance is the deviation of the control system. It gave some advices. Related Articles | Metrics

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Analysis of Noise Pollution and Control of   220 kV Outdoor Transformer Substations 2013, 33(5): 102-106.  DOI: 10.3969/j.issn.1006-1335.2013.05.022 Abstract ( )   PDF (1192KB) ( )   Noise pollution of urban 220kV outdoor substations is serious，it is necessary to make some research. Based on noise data of multiple 220kV outdoor substations, this paper described the major noise source, noise intensity, frequency characteristics, propagation characteristics and noise pollution situation of the 220kV outdoor substations. From the noise source and noise transmission routes, it briefly analyzed noise control measures of the 220kV outdoor substations. Examples were given to clarify the actual noise reduction effect of various noise reduction measures, which can be reference to the same project. Related Articles | Metrics

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Transverse Free Vibration of a Timoshenko Beam Rested on     Three-parameter Viscoelastic Foundation 2013, 33(5): 107-110.  DOI: 10.3969/j.issn.1006-1335.2013.05.023 Abstract ( )   PDF (937KB) ( )   The complex modal analysis is developed to study the transverse vibration of Timoshenko beams resting on three-parameter viscoelastic foundation. Complex frequency equations and modal function expressions are obtained for pinned-pinned ends. The effects of foundation parameters on natural frequencies and modal functions are analyzed in numerical examples, and the characteristics of Timoshenko beams are compared with Euler-Bernoulli beams. The results show that natural frequencies grow with increase in the stiffness and the shearing parameters, as well as decrease in the viscoelastic coefficients; the natural frequencies of Timoshenko beams are slightly less than Euler-Bernoulli beams. Related Articles | Metrics

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Study on the Characteristics of Low Frequency Noise of the Indoor Stationary Facilities and Its Assessment Method 2013, 33(5): 111-114.  DOI: 10.3969/j.issn.1006-1335.2013.05.024 Abstract ( )   PDF (1017KB) ( )   This study is recommended to establish an Emission standard for the noise of stationary facilities to fill the blank of the noise control in dwelling house. It is defined that the characteristics of the stationary facilities noise is a kind of Low-Frequency Noise (LFN), and its main band is in the range 20 ~ 250Hz. To represent the real subjective annoyance of the LFN, it is considered to use the difference between C- and A-weightings as a predictor of annoyance. If the difference is greater than 15dB, there is the potential for a low frequency noise problem. To develop an appropriate limit standard of stationary facilities in the residential construction noise will help to the interior environmental regulation and control. Related Articles | Metrics

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Test and Analysis of Airborne Sound Insulating Properties for      Building’s External Windows and Doors 2013, 33(5): 115-119.  DOI: 10.3969/j.issn.1006-1335.2013.06.025 Abstract ( )   PDF (1191KB) ( )   Abstract: The performance test for airborne sound insulating of the main building external doors and windows manufacturing facilities and typical product of doors and windows in Shanghai region were described in this paper. First, the effect on the open mode, the support structure material, glass thickness, type and fixation approach as well as traffic noise spectrum adaptation term were analyzed. Finally, The tester based on Lab inspection result for a good performance of doors and windows which apply to engineering application as sample, to qualify the performance. Related Articles | Metrics

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Sound Field Reconstruction Based on Patch Impedance  Coupling Approach 2013, 33(5): 120-125.  DOI: 10.3969/j.issn.1006-1335.2013.05.026 Abstract ( )   Abstract: The sound field radiated from three monopoles in a rectangular cavity has been reconstructed based on the patch impedance coupling approach in this study. A coupling surface surrounding all the sources in the cavity has been built to divide the total cavity into two independent spaces, i.e., source space (with the sources) and receiver space (without the sources), and it has also been divided into several patches. In the source pace, the pressure responses averaged across all the patches are together consisted of the pressure response distributed across the coupling surface, which is the blocked pressure; the coupling impedance among all the patches is the source impedance. The equivalent source has been got from the blocked pressure and the source impedance so that it can be used to reconstruct the sound field. The experiments demonstrated that when the size of the patch is approximate to 1/5~1/3 wavelength, the reconstructed sound field is stable and similar to the real sound field. Related Articles | Metrics

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Study on Chaotic Time Series Prediction of the Effect of  Phase Space Reconstruction 2013, 33(5): 126-130.  DOI: 10.3969/j.issn.1006-1335.2013.05.027 Abstract ( )   PDF (1806KB) ( )   Validity of reconstruction parameter is tested with the prediction of wavelet neural network. The prediction results of wavelet neural network are correct when input parameter number of the network equals to the embedded dimension of phase space reconstruction. Hence, the result of phase space reconstruction is evaluated through the prediction. The sensitivity of scale parameter in wavelet neural network is analyzed, and results show that the prediction curves are affected severely when it is too small. Learning rate of scale parameter should be smaller than others when it is updating, and the simulation shows that the prediction curves are satisfied with this advanced strategy. The mother wavelet Morlet function is selected, and only when the adjustable parameter of Morlet function is relatively small, the prediction is carried out well. Related Articles | Metrics

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Application of Wavelet Analysis of Curvature Modal to Damage Detection of Bridges 2013, 33(5): 131-135.  DOI: 10.3969/j.issn.1006-1335.2013.05.028 Abstract ( )   PDF (1205KB) ( )   In the paper, continuous wavelet transform (CWT) is applied to curvature modal analysis of simply supported beams with various defects. The results show that it is possible to determine the damage location of structural based on wavelet transform coefficients of curvatures of mode shapes. If the damage location is near to the equilibrium position of vibration, we can identify the damage location according to the superposition results of wavelet transform coefficients of curvatures of mode shapes. The further results show that there is no necessary relationship between the damage degree of structure and the wavelet transform coefficient. The peaks of wavelet transform coefficient only indicate the damage location of structural. It is necessary to explore other indicator to determine the quantitative relationship between the indicator and the damage degree. Related Articles | Metrics

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Self-adaptive Minimum Control Synthesis (MCS) Algorithm  of AMD System 2013, 33(5): 136-140.  DOI: 10.3969/j.issn.1006-1335.2013.05.029 Abstract ( )   PDF (1236KB) ( )   Related Articles | Metrics

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Application of Self-adaptive Kalman Filter in Bridge’s Health Monitoring System 2013, 33(5): 141-143.  DOI: 10.3969/j.issn.1006-1335.2013.05.030 Abstract ( )   PDF (823KB) ( )   For the strain mode indicators of bridge structure in bridge health monitoring, vibrating string strain sensor is usually to be used, but its noise source is a low-frequency vibration on bridge. The accuracy of information which is collected will be affected by low-frequency noise. In this paper, Adaptive Kalman Filter will be taken in the signal processing of strain mode indication. According to the feature of bridge detection signal to establish adaptive dynamic filtering model, at the same time, using this model to simulink actual strain monitoring data which comes from a bridge of Gansu. The result shows that the model can correctly reflect change of bridge strain modal indicators ,low-frequency noise could be effectively restrained, measurement accuracy could be improved, and could provide reliable data for bridge health assessment. Related Articles | Metrics

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Application of Signal Correlation and EEMD-Hilbert Envelope in Fault Diagnosis of Roller Bearings yuyanTONG 2013, 33(5): 144-149.  DOI: 10.3969/j.issn.1006-1335.2013.05.031 Abstract ( )   PDF (1563KB) ( )   Aimed at uncertainty about the center frequency and band width of the band-pass filter in the traditional signal envelope, and the mode aliasing problem of the empirical mode decomposition in processing the nonlinear and non-stationary signal, a new method of realizing the fault diagnosis of roller bearing in the early stage is put forward by using signal correlation as a criteria to get the optimal IMF component of the ensemble empirical decomposition(EEMD) ,then enveloping the IMF component and getting the demodulation spectrum by means of hilbert transform to derive the characteristic frequency of the fault pattern. The experimental analysis results show that the roller bearing fault patterns can be identified accurately and effectively by this method which is very appropriate to be used in the precise fault diagnosis of the roller bearing in the early stage, will be well applied in machinery equipment fault processing system. Related Articles | Metrics

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Fault Diagnosis Technology of Reciprocating Pumps Based on Compact Wavelet Neural Network 2013, 33(5): 150-154.  DOI: 10.3969/j.issn.1006-1335.2013.05.032 Abstract ( )   PDF (840KB) ( )   A method of the reciprocating pump fault diagnosis is proposed based on inlay model Wavelet Neural Network, in order to determine the fault type of the reciprocating pump accurately. This paper using the reciprocating pump single cylinder pressure as the characteristic signal of the system, extracting feature vector of the faults by wavelet packet decomposition, and at the same time, using this feature vector as the input signal of the wavelet neural network to determine the type of the fault. The examples of faults diagnosis of fluid end on a reciprocating pump show that the system fault diagnosis accuracy reached more than 94%. Related Articles | Metrics

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Design and Experimental Investigation of Metal Rubber Vibration Isolators for the Electric Controller of Vehicle’s Diesel 2013, 33(5): 155-157.  DOI: 10.3969/j.issn.1006-1335.2013.05.033 Abstract ( )   PDF (916KB) ( )   In this paper, the metal rubber vibration isolator for the vibration isolation and damping of vehicle diesel electric controller was introduced. The experimental research on the metal rubber vibration isolator was done. The influence rule of wire diameter and heat treatment condition on the elastic and damping properties of the metal rubber vibration isolator with the same physical dimension, forming pressure, blank mass, was emphasisly discussed. Related Articles | Metrics

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Active Control Method for Suppressing Mutual Interference      of Actuators 2013, 33(5): 158-160.  DOI: 10.3969/j.issn.1006-1335.2013.05.034 Abstract ( )   PDF (989KB) ( )   To solve the actuator mutual interference problem in the multi-channel active vibration control, control focus was adjusted and the coupling way of control channels was revised. By the revised way, positive feedbacks between the actuators have been suppressed effectively and control purpose has been achieved fast and stably. The revised way is based on the Filtered-x LMS(FxLMS) algorithm and the multi-channel control model. Control method is effective and stable. Realizing process is simple and practical. The experiment results show that this revised control method can effectively suppress interference between actuators, at the same time can meet higher overall control requirements. Related Articles | Metrics

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Anti-vibration Effects of Trapezoidal-sleeper Track on the Foundation of Composite Isolators 2013, 33(5): 161-165.  DOI: 10.3969/j.issn.1006-1335.2013.05.035 Abstract ( )   PDF (1335KB) ( )   Abstract：In order to study the effect of anti-vibration of ladder sleeper track based on the metal rubber-disc spring isolators to the ground surface and the building, the vibration problem of the environment around the subway was simplified to a plane strain problem in this paper. The paper built a two dimensional model of building-tunnel-ground with ABAQUS finite element software and applied the calculated acceleration of the track bed to the model. The paper studied the difference in the impact on anti-vibration for the environment between the composite isolator and the linear pad. The paper evaluated the composite isolator and studied the rule of the ground vibration. The result shows that the metal rubber-disc spring isolator could improve the anti-vibration effect and be able to replace the linear pad. The rule of the ground vibration caused by the subway train was researched and compared with the reference. Related Articles | Metrics

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Influence of Suspension Stiffness of Shock Absorber on Vibration Intensity of Diesel Engines 2013, 33(5): 166-169.  DOI: 10.3969/j.issn.1006-1335.2013.05.036 Abstract ( )   PDF (796KB) ( )   Only consider the influence of the stiffness of shock absorber,hypothesize diesel and bench are rigid body,Theoretically, analyzing the influence of the stiffness of shock absorber of diesel engine on vibration intensity,get the conclusion that the larger stiffness of shock absorber,the greater rigid motion of the unit.For the experimental data that can be obtained on bench suspension tests of someone diesel locomotive diesel,calculating vibration intensity value and evaluation level,Comprehensive analysis and results indicates that,reduce stiffness of shock absorber,Can effectively reduce the vibration intensity of hang diesel engine,and improve the diesel engine level of working state. Related Articles | Metrics

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Parameter Identification of Quasi-static Asymmetric Hysteresis Model for Wire-rope Isolators 2013, 33(5): 170-172.  DOI: 10.3969/j.issn.1006-1335.2013.05.037 Abstract ( )   PDF (925KB) ( )   The wire rope isolator has the obvious nonlinear hysteretic characteristics because of dry friction. In the existing literature, most of the parameter identification on hysteresis model was based on the initial zero deformation. In fact, there is some initial deformation while the isolator in the system. Because Wire rope isolator is strongly nonlinear, the hysteresis parameters are different as different initial deformation. In this paper, under the experimental hysteresis curve with rated load, considering the high stiffness and varying damping, a asymmetrical hysteresis model has been presented. The quasi-static model is given by the parameter identification. The results showed that the theory model is fitted with the experimental results. The model can well reflect the quasi-static non-linear stiffness and damping characteristics of the wire rope isolator. Related Articles | Metrics

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Application of Dynamic Vibration Absorber in  Flywheel Vibration Control 2013, 33(5): 173-178.  DOI: 10.3969/j.issn.1006-1335.2013.05.038 Abstract ( )   PDF (1268KB) ( )   Dynamic vibration absorber(DVA) for reduction of flywheel vibration was developed. Optimum tuning frequency and damping ratio of the absorber in damped system were derived by multi-variable multi-mutation adaptive genetic algorithm (MMAGA). Then mathematical formulae of the optimum parameters were obtained by regression analysis. Validating the rationality of design and verifying damping performance of DVA by simulating and testing. The conclusion showed that the optimum absorber can reduce vibration response of flywheel. MMAGA was suitable to calculating optimum parameters of the absorber efficiently. Simulation and test validated that the DVA can largely depress the vibration of flywheel. Related Articles | Metrics

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Calculation of Transmission Loss of Mufflers Based on the Method of Acoustic Mode of Pipeline 2013, 33(5): 179-183.  DOI: 10.3969/j.issn.1006-1335.2013.05.039 Abstract ( )   PDF (1005KB) ( )   Transmission loss is an important index in evaluating muffler’s acoustic performance. A new method called acoustic mode in pipeline instead of the traditional method was proposed in this paper to estimate transmission loss. It was applied in the muffler with the smaller sectional area on the inlet and outlet whose result is nearly correct and the process is very simple compared with the traditional method, improving the efficiency in computing the transmission loss. For the muffler with the larger sectional area on the inlet and outlet, because of amount of high secondary wave appears in the medium-high frequency, the traditional method has become invalid; but in the low frequency the result is consistent with the traditional method for the plane wave is the main acoustic wave in the pipeline. So the method of acoustic mode in pipeline can estimate the transmission loss at express speed. Related Articles | Metrics

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Application of Sound Resonator in Enclosure 2013, 33(5): 184-188.  DOI: 10.3969/j.issn.1006-1335.2013.05.040 Abstract ( )   PDF (1395KB) ( )   Related Articles | Metrics

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Design of Low-frequency Acoustic Muffler for a 40 Ton Boiler 2013, 33(5): 189-192.  DOI: 10.3969/j.issn.1006-1335.2013.05.041 Abstract ( )   PDF (1134KB) ( )   This article describes for the lower 40 tons gas boiler exhaust noise is a low frequency resistive muffler design. 40 tons of gas boilers, low-frequency noise, especially at frequencies 63 and 125Hz, the key ingredients affect the ambient noise standards. Our research by the acoustic characteristics of the sound-absorbing material, in accordance with the relevant fiber material of the above low frequency band acoustic fundamental constants ? and ?c; analysis of the flow resistivity of the porous material layer backing rigid wall, the associated low-frequency sound absorption coefficients changes. Gas boiler exhaust muffler flow resistance requirements at the same time, and thus the construction of the resistive muffler to carry out a comprehensive study, the design of a built-in rectifier cylindrical muffler. Acoustic measurements: 5m long, the φ2.4m outside diameter channel diameter φ1.6m built-in the overall fluid 0.6 m cylindrical smoke muffler in 31.5 to 125Hz low frequency band of 6-10dB noise reduction to solve the boiler operation over the issue of low-frequency noise, local environmental noise standards. Related Articles | Metrics

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Technical Parameters and Comfort Evaluation of Hearing Protectors zhongfuLI 2013, 33(5): 193-198.  DOI: 10.3969/j.issn.1006-1335.2013.05.042 Abstract ( )   PDF (867KB) ( )   Related Articles | Metrics

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Study on the Algorithm of Maximum Weighted Vibration Level 2013, 33(5): 199-203.  DOI: 10.3969/j.issn.1006-1335.2013.05.043 Abstract ( )   PDF (1229KB) ( )   Maximum vibration level is a commonly used indicator for environmental vibration. However, since the frequency resolution of the spectral estimation method is unable to meet the requirements of vibration level computation, the calculation results may different when applying different method. In the paper, three different methods on calculating maximum vibration level are given and discussed. Meanwhile, a fast high-precision incremental approach is proposed. The method has a time complexity of O(n). Related Articles | Metrics

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Analysis of Aerodynamic Acoustic Characteristics of   Chevron Nozzles 2013, 33(5): 204-209.  DOI: 10.3969/j.issn.1006-1335.2013.05.044 Abstract ( )   PDF (1748KB) ( )   Abstract: In order to study acoustic characteristics of jet flow from chevron nozzle, experimental and numerical methods are combined to investigate the influence of different penetration and chevron count on jet flow field、distribution of turbulence intensity、noise spectrum、directivity at Ma=0.12. Experimental method includes far-field and near-field measurement of sound pressure to explore how the sound wave transfers. Using all these methods, the relationship between flow field and acoustic field is explored. The calculation and analysis shows that with the increase of penetration, chevron nozzle may strengthen the decrease of low frequency noise and the increase of high frequency noise ;with the increase of chevron count, chevron nozzle may significantly reduce overall sound pressure level almost in the whole range. Related Articles | Metrics

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Sound Transmission Loss Measurement by Using Two-microphone Method in a Standing-wave Pipe 2013, 33(5): 210-212.  DOI: 10.3969/j.issn.1006-1335.2013.05.045 Abstract ( )   PDF (1022KB) ( )   The sound transmission performance of the acoustical material can be measured in the standing-wave pipe by using the two-microphone method. The front surface impedances of the acoustical material can be determined if the beck surface impedances are known, so the arguments which are associated with the four elements of the transfer matrix can be calculated, and the sound transmission loss of the acoustical can be easily obtained. Several samples have been tested in the standing-wave pipe, compared with the experimental results from the four-microphone method, we know that the two-microphone method can be used to measure the sound transmission loss. Related Articles | Metrics

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Experimental Analysis and Control of the Noise of  a Natural Gas Compressor 2013, 33(5): 213-218.  DOI: 10.3969/j.issn.1006-1335.2013.05.046 Abstract ( )   Through the analysis of natural gas compressor noise sources and their characteristics, and according to noise data measured at site, it is concluded in this paper that the compressor noise is mainly caused by fluctuations of gas pressure in the cylinder, especially the air column resonance inside third cylinder. Finally, we have carried out the effective control according to the above analysis results and the average sound pressure level has been reduced from original 89.7dB to 72.4dB with approximately 17dB to fulfill the expected requirements. Related Articles | Metrics