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    18 April 2015, Volume 35 Issue 2 Previous Issue    Next Issue

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    Review of Mechanical Looseness Phenomena and Failure Characteristics Study
    2015, 35(2): 1-6.  DOI: 10.3969/j.issn.1006-1335.2015.02.001
    Abstract ( )   PDF (1052KB) ( )  

    There is a looseness phenomena existing in mechanical system widely which includes foundation looseness, pedestal looseness and match of components looseness, causes of the three types of looseness were explained by illustrated. Some common kinds of looseness models applied by domestic and foreign scholars were concluded. Research of single looseness, looseness coupled with rub-impact, looseness coupled with crack, looseness at two supports, slowly varying mass rotor system with looseness and two-span rotor system with looseness was expounded from the aspect of the dynamics modeling, solving method and their nonlinear dynamics characteristics. Research of looseness experiments were also introduced briefly. Finally, the key problem or further study of looseness fault was prospected.

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    Influence of Ocean Current Impact on Fluid-structure Coupled Vibration of Deep-sea Mining Equipment’s Hydraulic Pipelines
    2015, 35(2): 7-10.  DOI: 10.3969/j.issn.1006-1335.2015.02.002
    Abstract ( )   PDF (1225KB) ( )  
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    QPSO Algorithm-based Noise Optimal Design of Submerged Ring-stiffened Cylindrical Shells
    2015, 35(2): 11-14.  DOI: 10.3969/j.issn.1006-1335.2015.02.003
    Abstract ( )   PDF (1181KB) ( )  
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    Discussion on Damping Models for Seismic Response Analysis of Container Cranes
    2015, 35(2): 15-18.  DOI: 10.3969/j.issn.1006-1335.2015.02.004
    Abstract ( )   PDF (1481KB) ( )  
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    Reconstruction of AUV Radiation Acoustic Fields Based on Cylindrical NAH
    2015, 35(2): 19-23.  DOI: 10.3969/j.issn.1006-1335.2015.02.005
    Abstract ( )   PDF (1705KB) ( )  
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    Simulation and Experiment of Cabin Radiation Acoustic Field Using FEM/BEM Methods
    2015, 35(2): 24-27.  DOI: 10.3969/j.issn.1006-1335.2015.02.006
    Abstract ( )   PDF (1438KB) ( )  

    To solve the radiation noise problem of cabin structure, the vibration and acoustic radiation characteristics from the cabin was calculated by finite element and boundary element methods in time-domain. The FEM model of an analog cabin was established, and the modal test was done. The vibration mode is analyzed numerically and experimentally and validated the accuracy of this model. The experiment on vibration and sound radiation was done, and the acoustic pressure frequency response of the analog cabin was acquired. Transient response of the analog cabin structure was calculated by ANSYS. The response results of the BEM model were input to Virtual Lab, and the radiated acoustic field inside the analog cabin was calculated by indirect boundary element method. Through comparison, the result of simulation is consistent with the experimental data. It shows that this method is feasible and has theoretical guidance meaning for the control of civil aircraft cabin noise.

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    Calculation Method of Structural Vibration of Axial Flow Pumps Induced by Fluid Pressure Pulsation
    2015, 35(2): 28-31.  DOI: 10.3969/j.issn.1006-1335.2015.02.007
    Abstract ( )   PDF (1715KB) ( )  

    Vibration of the pump is partly caused by the pressure pulsation of the unsteady fluid in the pump, and the calculation method is very worth to study. The structure vibration response caused by fluid pressure pulsation of the axial flow pump is simulated through finite element analysis software, the calculation data were compared with the test results after processing, and the accuracy and feasibility of the method was analyzed. The results show that the calculation method can be used for forecasting blade-pass frequency vibration, and if increase the number of sampling points, recognition ability of high order harmonic frequency can be improved.

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    Application of Wave Propagation Method to Vibration Analysis of Rod-and-Beam Structures with Arbitrary Boundary Conditions
    2015, 35(2): 32-35.  DOI: 10.3969/j.issn.1006-1335.2015.02.008
    Abstract ( )   PDF (1100KB) ( )  
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    Dynamic Characteristics of a Bistable Piezoelectric Vibration Generator under Random Excitation
    2015, 35(2): 36-40.  DOI: 10.3969/j.issn.1006-1335.2015.02.009
    Abstract ( )   PDF (1274KB) ( )  
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    Modal Simulation and Test of Stator End Winding of a Large Turbo-generator
    2015, 35(2): 41-43.  DOI: 10.3969/j.issn.1006-1335.2015.02.010
    Abstract ( )   PDF (1168KB) ( )  
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    Measurement and Analysis of Noise in Metro Vehicle Compartments on Operation Lines
    2015, 35(2): 44-46.  DOI: 10.3969/j.issn.1006-1335.2015.02.011
    Abstract ( )   PDF (1321KB) ( )  

    With tape-A1 vehicles of Guangzhou Metro line-1 as the object of research, the measurement and analysis system of multi channels was used to test and analyze the noise in metro vehicle compartment when the vehicle runs on operation line.The data of noise in metro vehicle compartment in different blocks of line-1 was acquired, it shows that when curve radius is shorter than 600m,the main frequency band of noise in metro vehicle compartment was between 630Hz and 1000Hz, with the increasing of curve radius, different frequency bands of noise become more even, the main frequency band is gradually not obvious; The high frequency noise is affected greater than the low by speed.The measurement and analysis provides basis data for design and maintenance of metro vehicles and subway lines.

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    Improvement of Wheels for Noise Reduction by Replacing Sound Absorber Slices by Sound Absorber Rings in Beijing Subway Line 10
    2015, 35(2): 47-50.  DOI: 10.3969/j.issn.1006-1335.2015.02.012
    Abstract ( )   PDF (1353KB) ( )  
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    Feature Extraction of Lateral Damper Performance Degradation of High-speed Trains
    2015, 35(2): 57-60.  DOI: 10.3969/j.issn.1006-1335.2015.02.014
    Abstract ( )   PDF (1154KB) ( )  

    Lateral dampers are important units in high-speed train bogie, their performance degradation assessment is more effective for proactive maintenance. The Empirical Mode cross-correlation method (EMCC) is developed based on Ensemble Empirical Mode Decomposition, and the Empirical Mode cross-correlation coefficient is defined to describe the cross-correlation between two signals in the time domain. The proposed method is applied to extract and analyze the feature of vibration signals of high-speed train bogie’s lateral damper performance degradation from 90% to 10% that are divided into four degenerate intervals, the average precision is 95.2%,then quantitative degradation of test data could be realized and verified this method’s feasibility and validity.

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    Vibration Analysis of a Vehicle Suspension System with an  Anti-roll Bar by Matlab/Simulink Simulation
    2015, 35(2): 61-64.  DOI: 10.3969/j.issn.1006-1335.2015.02.015
    Abstract ( )   PDF (1342KB) ( )  

    The roll performance of the anti-roll bar of a certain type of vehicle was studied. A four-DOF mathematical model of suspension with anti-roll bar was established based on a half vehicle. Simulation model for the whole system was completed by means of Matlab/Simulink. The response curves under random road profile excitation and the stiffness coefficient of the anti-roll bar were given as the input. The response curves of the body vertical velocity, the body roll angle and the suspension dynamic deflection were got. Compared with those without anti-roll bars, research results prove that the body roll angle is reduced obviously by way of using anti-roll bar, meanwhile, the vehicle handling stability and ride comfort is improved.

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    Decoupling and Optimal Design of a Powertrain Mount System Based on Matlab
    2015, 35(2): 65-68.  DOI: 10.3969/j.issn.1006-1335.2015.02.016
    Abstract ( )   PDF (1072KB) ( )  

    It’s known that powertrain mount system is playing important role in vehicle design after analysis. When idle running, the car steering wheel violently shaking. Powertrain and suspension parameters have been measured, and the six degrees of freedom mathematical model of powertrain mount system have been established. It’s found that the coupling is serious in all directions by decoupling calculation, therefore system optimization design have to been done. firstly the mount position need to been adjusted by the theory of impact center, secondly mount system range of rigidity and mount Angle are chosen as constraint variables, after that fgoalattain of multi-objective optimization function of Matlab is used, and the minimum decoupling rate of 6 direction is set as the objective function for optimization design, the results showed that this method can realize better decoupling in all directions within a certain range of constraints and have high practical values.

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    Application of Acoustic Sensitivity Analysis to a Van’s Body
    2015, 35(2): 69-72.  DOI: 10.3969/j.issn.1006-1335.2015.02.017
    Abstract ( )   PDF (1668KB) ( )  

    the vibration and noise of a particular type of van increases dramatically under certain working conditions, which lowers its comfort. The results of modal tests and simulations were compared to justify the accuracy of finite element model. Then, the acoustic sensitivity of van body was simulated on software and the left mount point, right mount point as well as the back mount point were stimulated in different directions to obtain the acoustic pressure signal of these answering points. The results show that different aspiration points have different impacts on the acoustic pressure signal of answering points; the direction of aspirations affect the acoustic pressure of answering points as well; at 36Hz and 111Hz, the local vibration of van body's top cover generates the severe noise. The results have provided the bases of further improvement of van body.

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    Noise Control Method of Interior Booming Induced by Torsional Vibration of Driveline Systems
    2015, 35(2): 73-76.  DOI: 10.3969/j.issn.1006-1335.2015.02.018
    Abstract ( )   PDF (1211KB) ( )  

    A rear-drive mini bus exists the booming problem at low engine speed, which is demonstrated to be caused by the driveline torsional vibration. At first beginning, the mechanism of driveline torsional vibration’s effects on interior noise was analyzed. Afterwards, equivalent system of driveline was established and free vibration was calculated. To obtain the engine exciting torque, an engine simulation model was built, and then, forced vibration calculation was carried out. In order to verify the model, experiment of driveline torsional vibration measurement was conducted, and the model was proven to be acceptable. Then the verified model was used to research characteristics of driveline torsional vibration. In order to reduce torsional vibration amplitude of the final drive, from the perspective of reducing torsional excitation transfer to body, a series solutions were proposed which were proven effective to improve low engine speed booming by real test. This research can provide some references for solving the similar engineering problem.

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    Analysis of Idle Abnormal Sound of an SUV
    2015, 35(2): 77-79.  DOI: 10.3969/j.issn.1006-1335.2015.01.019
    Abstract ( )   PDF (1516KB) ( )  

    In this paper, abnormal noise source for a SUV , which has the abnormal sound as ‘buzz’ at idling condition, can be identified rapidly, by using of various identification approaches for noise source, such as spectrum analysis, acoustic interactive filtering, the subjective evaluation, the near-field measurement, lead wrap and so on. Then the radiated noise can be optimized and reduced significantly by the modal analysis method, and finally the interior sound quality can be improved obviously.

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    Research on NVH Optimization Technique of  Body-in-White Structures
    2015, 35(2): 80-85.  DOI: 10.3969/j.issn.1006-1335.2015.02.020
    Abstract ( )   PDF (1852KB) ( )  

    In order to improve the performance of noise, vibration & harshness (NVH) of a full vehicle, a structure optimization process is proposed, expecting to achieve a large improvement on NVH performance by making a minor modification to the vehicle. As an example, a commercial vehicle is used to perform this process. Initially, modal analysis, sensitivity analysis, panel acoustic contribution and structural - acoustic analysis, etc. are used to find parts which significantly affect vehicle NVH performance. In the second stage, according to different parts, the corresponding structure optimization method is proposed. Based on the structure analysis of the roof, a corresponding topology optimization solution is presented, by which the natural frequencies and the NVH performance of BIW can be improved.

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    Noise Evaluation Method for Starting Motors of Passenger Cars
    2015, 35(2): 86-90.  DOI: 10.3969/j.issn.1006-1335.2015.02.021
    Abstract ( )   PDF (1396KB) ( )  

    Starting motor noise is an important factor to define the passenger car quality and its objective evaluation is a major issue to qualify the perceived sound quality. To deal with this issue, an objective evaluation method, using order analysis, is proposed based on the subjective assessment results of motor noise. The subjective evaluation of fifteen sample motors was carried out using the ranking scale method. Testing results show that eight motors are perceived as acceptable. The highest orders of the acceptable motors were extracted under idle and load conditions to build the key group of critical orders. Then, by extracting the envelope of the critical orders, the threshold for objective judgment of starting motor noise of passenger car has been established. The proposed method provides an alternate choice to evaluate motor noise for engineers.

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    Study on Jet Noise Separation Technique of Turbofan Engines
    2015, 35(2): 91-95.  DOI: 10.3969/j.issn.1006-1335.2015.02.022
    Abstract ( )   PDF (1197KB) ( )  
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    Technology of Satellite Segment Vibration Test
    2015, 35(2): 96-100.  DOI: 10.3969/j.issn.1006-1335.2015.02.023
    Abstract ( )   PDF (1655KB) ( )  

    The vibration test technology of satellite segment is studied in this paper. Based on minimizing the test points’ accumulated relative errors between entirety and segment vibration test, the algorithm solving the input acceleration spectral for satellite segment vibration test is derived. Vibration tests are carried out on both satellite entirety and its segment using the method mentioned above. The results show good coincidences between tests and theory, and the response differences between entirety and segment tests depend on their dynamical characters. The algorithm presented in this paper ensures the segment responses to be the best approximation of entirety responses.

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    Experimental Study on Ambient Building Damage Caused by Heavy-haul Railway Operation
    2015, 35(2): 101-106.  DOI: 10.3969/j.issn.1006-1335.2015.02.024
    Abstract ( )   PDF (1550KB) ( )  

    This paper selects four representative residential buildings along the railway as research objects, all of which are of one layer brick-concrete structure, and the distances are 6.5m, 15m, 26m and 38m respectively away from the railway, where 15m buildings’ damage can be used as typical samples. Field test and analysis are conducted on the foundations and roofs’ vibration, at the same time, comparing the PPV results measured data with Chinese and foreign related standards. Results showed that, when the PPV is greater than the third class vibration limits in GB 50868-2013, the poor quality buildings along railways of our country will damage.

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    Experimental Study on Automatic Identification of Moving Train Load Parameters of Bridges
    2015, 35(2): 107-111.  DOI: 10.3969/j.issn.1006-1335.2015.02.025
    Abstract ( )   PDF (1529KB) ( )  

    A new system for moving train load parameters identification is presented and experimental studies are proceed based on a simply supported steel beam with uniform cross-section and moving train model. The time history displacements of measurement stations on bridge are simultaneously measured by using displacement image processing monitoring system. Basic parameters of the model train, including moving speed, axle numbers and axle spacing, are identified with a parameter acquisition system. Finally moving train loads are identified by using multi-axle moving loads identification system. Effects of parameters for different moving speeds and measurement stations on the proposed system are investigated. The result shows that this system is a feasible and accurate method for moving train load parameters identification and makes preparations for the practical application.

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    Key Influencing Parameters for Traffic Noise Prediction of Highways
    2015, 35(2): 112-115.  DOI: 10.3969/j.issn.1006-1335.2015.02.026
    Abstract ( )   PDF (1175KB) ( )  

    Vehicle flow, vehicle type ratio and vehicle speed are key parameters when predicating traffic noise. Based on actual investigation of a typical highway in Sichuan, road traffic noise in different locations is calculated adapting the method recommend by Technical Guidelines for Noise Impact Assessment (HJ 2.4-2009). Through comparison between the predicted values and the actual monitoring ones, we can conclude: 1) traffic noise predicted using design speed or measured speed is close to the measured traffic noise; 2) choosing measured speed and taking the entire highway as a whole is better than other lane group strategies for forecasting traffic noise; 3) using the vehicle type ratio measured at night is more suitable for predicating nightly traffic noise than employing the diurnal vehicle type ratio measured in the daytime.

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    Numerical Analysis of Ground Vibration Amplification Phenomenon Caused by Subway Operation
    2015, 35(2): 116-120.  DOI: 10.3969/j.issn.1006-1335.2015.02.027
    Abstract ( )   PDF (1463KB) ( )  
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    Experimental Study on Annoyance of Duration Time for   Aircraft Flyover Noise
    2015, 35(2): 121-125.  DOI: 10.3969/j.issn.1006-1335.2015.02.028
    Abstract ( )   PDF (1372KB) ( )  

    Aircraft flyover noise was a major source of community annoyance. According to the acoustic characteristics of flyover noise, stimulus signals were simulated to analyze the effect factors on annoyance in single flyover event. Loudness based on Moore method was calculated for stimulus signals. An annoyance test was conducted in acoustic laboratory to assess the correlation among duration time, loudness and annoyance. Questionnaire surveys were used to assess the effects of subjects’ characteristics on annoyance. The result showed that there was a strong correspondence between duration time and annoyance at same onset rate and peak sound level. Long duration time leaded to high annoyance. Due to the sensory adaption effect of human ears, annoyance sensitivity decreased if a noise signal lasted too long. Annoyance increased with loudness exceed 10% of the time (N10) obeying a linear correlation. Questionnaire surveys showed that gender was not significant to annoyance. Annoyance of high earphone utilization subjects was lower than low earphone utilization ones. Long-term usage of earphone leaded to sensory decrease on noise.

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    Noise Impact Control Measures of Aircrafts in Foreign Airports
    2015, 35(2): 126-130.  DOI: 10.3969/j.issn.1006-1335.2015.02.029
    Abstract ( )   PDF (1070KB) ( )  
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    Discussion on Domestic Rural Noise Pollution Status and Its Control Measures
    2015, 35(2): 131-136.  DOI: 10.3969/j.issn.1006-1335.2015.02.030
    Abstract ( )   PDF (1362KB) ( )  

    Basic on statistical analysis of a large number of domestic highway construction project environmental assessment, completion and the accumulation of traffic noise monitoring data in the research process since 2005, we form the basic judgment on the current situation of noise pollution in Chinese rural, recognizing the main pollution source of noise is traffic noise, investigating attention-degree of the rural residents to the noise problem by questionnaire and interview. there are several things such as the environmental monitoring mechanism , the present measures of noise reduction effect and characteristics, the implementation we could do to analysis main problems of present rural acoustic environment pollution prevention and control in existence, and put forward some improvement suggestions of rural noise pollution.

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    Acoustic and CFD Analyses for Noise Control of  a Small Excavator
    2015, 35(2): 137-140.  DOI: 10.3969/j.issn.1006-1335.2015.02.031
    Abstract ( )   PDF (1454KB) ( )  

    In view of the big radiated noise of a small excavator, the exhaust noise was identified as the main noise source, using spectrum analysis method. The sound field and CFD of the original muffler were simulated. The simulation results show that the noise elimination of original muffler is obviously insufficient from 100 Hz to 160 Hz. The parameters of a impedance mixed muffler with three tubes were optimized. The effect of perforation rate, diameter of the perforation, diameter of the middle tube and insertion depth of the inlet on transmission loss were analyzed. The results show that perforation rate and diameter of the perforation has little effect on the transmission loss, and the smaller the diameter of the middle tube, the deeper the insertion, the better the noise elimination in low and median frequency.The test results show the optimized muffler is silencer in low and median frequency, which are consistent with the results of the analysis. The radiated noise reduces by 3.1dB(A), in the meanwhile, the back pressure of the exhaust decreases by 86.1%.

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    Measurement of Sound Pressure Level of Simple Acoustic Sources in Noisy Environment with Mini-sized
    2015, 35(2): 141-145.  DOI: 10.3969/j.issn.1006-1335.2015.02.032
    Abstract ( )   PDF (1374KB) ( )  

    A regular sound level meter cannot tell the difference between the target’s acoustic pressure and the environment noise pressure, it always gives the measured total acoustic pressure. To improve the measurement accuracy of the sound pressure level of target sound source in noisy environment, the acoustic wave separation method based on spherical wave superposition was used, with input of acoustic pressures measured by a mini-sized microphone array.The impact of parameters on the accuracy of sound pressure level were examined in anechoic chamber, the results showed that a reasonable accuracy can be obtained when the frequency range is from 500Hz to 2750Hz and the measurement distance is from 5cm to 12cm.

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    Application of Cadna A to Noise Reduction Prediction of Natural Ventilation Cooling Towers
    2015, 35(2): 146-149.  DOI: 10.3969/j.issn.1006-1335.2015.02.033
    Abstract ( )   PDF (1706KB) ( )  
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    Influence of Different Lengths of Longitudinal Sleepers on Vibration Damping Performance of Ladder Tracks
    2015, 35(2): 150-153.  DOI: 10.3969/j.issn.1006-1335.2015.02.034
    Abstract ( )   PDF (1421KB) ( )  
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    Fault Diagnosis of Wind Turbine Gearbox Based on Wavelet Packet and Back Propagation Neural Network
    2015, 35(2): 154-159.  DOI: 10.3969/j.issn.1006-1335.2015.02.035
    Abstract ( )   PDF (1430KB) ( )  
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    An Improved LMD-based Denoising Algorithm for Fault Diagnosis of Rotating Machinery
    2015, 35(2): 160-164.  DOI: 10.3969/j.issn.1006-1335.2015.02.036
    Abstract ( )   PDF (1805KB) ( )  
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    Engine Fault Diagnosis Based on Adaptive Fuzzy Neural Network
    2015, 35(2): 165-169.  DOI: 10.3969/j.issn.1006-1335.2015.02.037
    Abstract ( )   PDF (1661KB) ( )  

    The engine is the core component of the vehicle, timely and effective manner to discover and troubleshooting, reduce maintenance costs, reduce economic losses, increase the reliability of the engine at work to avoid accidents have great significance. Taking a model engine for the study, with testing techniques, signal processing, analysis, neural networks and fuzzy control theory, and come out adaptive fuzzy neural network fault diagnosis engine.The paper established a fault signal acquisition engine test stand and four kinds of artificial conditions, the vibration signal acquisition normal operating conditions and abnormal operating conditions by the acceleration sensor, and then using wavelet theory collected vibration signal de-noising process, improve signal to noise ratio and extract the fault characteristic value of the signal sample data as the network training and testing. Fuzzy neural network training and testing using sample data adaptive, that is pattern recognition engine failure, through simulation, and achieved good diagnostic results. Compared with the traditional BP Neural Network diagnostic methods, both in learning speed or accuracy of the diagnosis, Fuzzy Neural Network has more advantages in fault diagnosis.

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    Denoising of Rotor Vibration Signals Based on  Improved EMD-Wavelet Analysis
    2015, 35(2): 170-174.  DOI: 10.3969/j.issn.1006-1335.2015.02.038
    Abstract ( )   PDF (1461KB) ( )  

    For de-noising from low SNR rotor vibration signal, a method based on EMD and wavelet analysis is proposed. Firstly, the noisy signal is decomposed by EMD, and the IMF components are divided to high and low frequency by using consecutive mean square error(CMSE). Then, different thresholds are determined and the useful signal details of high and low frequency IMF components are extracted based on wavelet analysis and combined with the low-frequency IMF components so that the noise of IMF is removed efficiently. Numerical simulation and rotor vibration signal were carried out to evaluate the performance of the proposed method. The results showed that the proposed method outperformed the EMD and wavelet threshold de-noising algorithm.

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     Fault Diagnosis of Helicopter Rotor’s Unbalance Based on  PSO-GRNN Algorithms
    2015, 35(2): 175-179.  DOI: 10.3969/j.issn.1006-1335.2015.02.039
    Abstract ( )   PDF (1254KB) ( )  

    In order to diagnose the helicopter rotor’s unbalance fault accurately, a method based on particle swarm optimization (PSO) algorithm and generalized regression neural network (PSO-GRNN) is proposed. The average mean square error got from cross validation is used as the fitness function of particle swarm, then the optimal GRNN smooth factor is attained by using particle swarm optimization (PSO) algorithm ,and an optimal model for fault diagnosis is achieved finally. It can be concluded that ,based on the PSO - GRNN model ,the type and the degree helicopter rotor’s unbalance can be diagnosed effectively, the accuracy rate of fault type is up to 94.29% and the maximum error of fault degree is only 6.54%, which is perfectly satisfied for the requirement of project.

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    Experimental Study on Rub-impact Faults of High-speed Aerostatic Bearing-rotor Systems
    2015, 35(2): 180-183.  DOI: 10.3969/j.issn.1006-1335.2015.02.040
    Abstract ( )   PDF (2257KB) ( )  

    Based on the structure of single span, four disk, the high-speed aerostatic bearing-rotor system test-bed is established and the rubbing fault of the system was researched. In the test, axial rubbing, radial rubbing, rubbing caused by low frequency and rubbing caused by working frequency have been presented. When the frequency fpectrum characters, shaft orbit, bifurcation diagram and time-frequency-amplitude waterfall diagrams have been analyzed, the typical features of all kinds of rubbing fault are given and the difference between them were analyzed. The experiment basis for rubbing fault identification and establishment of the diagnosis system is provided.

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    Validation of the Accuracy of Hybrid Transfer Path Analysis (TPA) Method
    2015, 35(2): 184-187.  DOI: 10.3969/j.issn.1006-1335.2015.02.041
    Abstract ( )   PDF (1462KB) ( )  

    This paper introduces the calculation method of Hybrid TPA, which based on the basic principle of traditional TPA method, combined with the transfer functions calculated by the finite element model, So as to reduce the workload and shorten the test cycle. On torsional vibration problem of vehicles drive systems, the TPA model was established. It can help the accurate recognition of the load force between auxiliary frame and body, and confirmation for the more contributable transfer paths, and the vector superposition for contribution from every transfer path, and the target value of sound pressure inside the car can be gotten by the above. Comparing the sound pressure color map with results directly measured in the test, the fault characteristics of the problem frequencies were recreated, while the accuracy of the method was proved.

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    Analysis of Damage Modes of a Ship’s Stiffened Plate Subjected to Bubble Jet Loading Based on ALE Method
    2015, 35(2): 188-193.  DOI: 10.3969/j.issn.1006-1335.2015.02.042
    Abstract ( )   PDF (1786KB) ( )  
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    Experimental Study and Parameter Analysis of  Nonlinear Metal-rubber Isolators
    2015, 35(2): 194-200.  DOI: 10.3969/j.issn.1006-1335.2015.02.043
    Abstract ( )   PDF (1528KB) ( )  

    The parameters change rule of nonlinear Metal Rubber isolator under the conditions of different incentives was studied in this paper. To a certain type of Metal Rubber isolator as the research object. Firstly, the static experiment and the dynamic experiment under the conditions of different sine excitations were done. Secondly, the functional constitutive relation model based on double broken line was established. Thirdly, the parameters of the Metal Rubber isolator worked in the conditions of different incentives were identified by Particle Swarm Optimization. The parameters change rule of the nonlinear Metal Rubber isolator under the conditions of different incentives was got by comparison with the experimental results and the identification results. The result showed that dynamic experiment should be done and the right parameters should be identified under the right incentives before the analysis of a nonlinear Metal Rubber vibration isolation system. The results of the study in this paper provide a general method for the dynamics analysis of the Metal Rubber vibration isolation system.

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    Simulation and Analysis of Noise Attenuation Performance of  the Wheel Loader’s Muffler
    2015, 35(2): 201-204.  DOI: 10.3969/j.issn.1006-1335.2015.02.044
    Abstract ( )   PDF (1671KB) ( )  

    Three-dimensional acoustic finite element method was employed to investigate the effect of the axial angle of the inlet and outlet on the acoustic attenuation performance of the muffler. The results show that the axial angle of the inlet and outlet were affected at low and mid frequencies, especially, when the value of the axial angle is 60, the improved muffler has better acoustic performance. For the effect of it on the acoustic attenuation performance, the axial angle of the inlet and outlet provides the good advice for the design of the muffler.

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    Analysis and Experiment of Isolators for Micro-vibration Control
    2015, 35(2): 205-208.  DOI: 10.3969/j.issn.1006-1335.2015.02.045
    Abstract ( )   PDF (1373KB) ( )  
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    Study on Explicit Integration Used for Solving the Stiffness of Rubber Element
    Jia LI
    2015, 35(2): 209-212.  DOI: 10.3969/j.issn.1006-1335.2015.02.046
    Abstract ( )   PDF (1501KB) ( )  

    The vertical static stiffness of rubber element is solved by the explicit integration and implicit integration, and three loading functions are chosen in explicit integration. It is indicated by simulation analysis and experimental results that the kinetic energy of ramp function exists the oscillation, while the kinetic energy of smooth and sine function exists the no oscillation during the initial step time. In the large-strain, implicit integration is failing because of mesh distortion, then the explicit integration is high-efficiency and the simulation results are consistent with experimental results, the maximum error is 5.7%. It is efficient that the explicit integration is used for solving the large-strain stiffness of rubber element and the different loading functions affect the simulation results directly, especially during the initial step time.

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    Active Absorption Measurement of Panels Using Multichannel Inertial Absorbers in Wideband Frequencies
    2015, 35(2): 213-216.  DOI: 10.3969/j.issn.1006-1335.2015.02.047
    Abstract ( )   PDF (1394KB) ( )  

    Lots of research is carried out on the proof mass which uses the electromagnetic effect to output force,proof mass has the property of fast response and moderate force,this is suitable for the flexible material.In reality the vibration is from multiple sources and is distributed widely, multiple proof masses are needed to achieve the gloabel control..In this test four proof masses are distributed to implement control,the control frequency between 20Hz and 120Hz covers the first two resonance frequencies.The velocity feedback control algorithm which means the active damping is adapted to implement control,the effect dominates at the resonance frequencies and this is obvious in the test result.

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    Study and Experimental Verification on a Dynamic Vibration Absorber with Frequency Adjustable
    2015, 35(2): 217-221.  DOI: 10.3969/j.issn.1006-1335.2015.02.048
    Abstract ( )   PDF (1652KB) ( )  

    A dynamic vibration absorber with frequency adjustment installed in the maximum resonance displacement point of the pipeline which plays an role in reducing the piping vibration under different natural frequencies by moving the position of mass block on the leaf spring has been designed based on the principle of anti-resonance.A space pipeline has been built.The ability of designed dynamic vibration absorber to damp the pipelines which possess different natural frequencies within the available range of frequency has been validated via finite element analysis and pipeline vibration test.The result shows that the best damping effect of dynamic vibration absorber through adjusting the position of mass block on the leaf spring. And the best installation location is the maximum resonance displacement of the pipes.The application value of the designed dynamic vibration absorber has been indicated.

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    Structure Optimization and Radiation Noise Analysis of   Air Cleaners
    2015, 35(2): 222-225.  DOI: 10.3969/j.issn.1006-1335.2015.02.049
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