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    18 August 2014, Volume 34 Issue 4 Previous Issue    Next Issue

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    Structure-borne Sound Transfer Path of a Low-floor Vehicle  and Its Interior Noise Property
    2014, 34(4): 1-4.  DOI: 10.3969/j.issn.1006-1335.2014.04.001
    Abstract ( )   PDF (1727KB) ( )  
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    Influence of Hanger’s Stiffness on the Modals of Vehicle’s Body and Equipments
    2014, 34(4): 5-9.  DOI: 10.3969/j.issn.1006-1335.2014.04.002
    Abstract ( )   PDF (1352KB) ( )  

    Model is one of the important characteristics of the vehicle, including vehicle model and hanging equipment model. The model frequencies of the vehicle will vary with the change of various factors. Considering the elastic models of car body, it is equivalent to the Euler Bernoulli beam. Based on the finite element model of a certain type of high speed train and ANSYS simulation software, the regulation of model frequency has been given though studying the frequency and MAC of model under different hanging vertical, horizontal, vertical stiffness. It provides the basis for modal test and engineering calculation.

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    Influence of Out-of-roundness of Wheels of High-speed Trains on Interior Vibration and Noise
    2014, 34(4): 10-13.  DOI: 10.3969/j.issn.1006-1335.2014.04.003
    Abstract ( )   PDF (1342KB) ( )  
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    Sound Radiation Characteristics of Extruded Aluminum
    2014, 34(4): 14-19.  DOI: 10.3969/j.issn.1006-1335.2014.04.004
    Abstract ( )   PDF (1604KB) ( )  
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    Experimental Study on Interior Noise Source Identification for 100 % Low-floor Railway Trains
    2014, 34(4): 20-23.  DOI: 10.3969/j.issn.1006-1335.2014.04.005
    Abstract ( )   PDF (1638KB) ( )  
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    Influence of Wheel Structure on the Noise in Bogie Area
    2014, 34(4): 24-29.  DOI: 10.3969/j.issn.1006-1335.2014.04.006
    Abstract ( )   PDF (1790KB) ( )  
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    Analysis of Vibration and Sound Radiation Characteristics of Sprayed Damping Wheels
    2014, 34(4): 30-34.  DOI: 10.3969/j.issn.1006-1335.2014.04.007
    Abstract ( )   PDF (2266KB) ( )  
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    Effect of Sound Insulation Pad on Sound Transmission Loss Property of Interior Floor of High Speed Trains
    2014, 34(4): 35-38.  DOI: 10.3969/j.issn.1006-1335.2014.04.008
    Abstract ( )   PDF (1122KB) ( )  
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    Sound Transmission Loss of Sandwich Panels Floor of High-speed Trains
    2014, 34(4): 39-43.  DOI: 10.3969/j.issn.1006-1335.2014.04.009
    Abstract ( )   PDF (1538KB) ( )  
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    Experimental Study on the Sound Insulation Performance and Noise Reduction Effect Prediction of V-type Noise Barriers
    2014, 34(4): 44-47.  DOI: 10.3969/j.issn.1006-1335.2014.04.010
    Abstract ( )   PDF (1420KB) ( )  
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    Influence of Sprayed Damping Thickness on Vibration and Sound Radiation of Damped Wheels
    2014, 34(4): 48-51.  DOI: 10.3969/j.issn.1006-1335.2014.04.011
    Abstract ( )   PDF (1178KB) ( )  
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     Experiments on Vibration and Noise Reduction Effect of Sprayed-damping Section Aluminum Applied to High-speed Trains
    2014, 34(4): 52-55.  DOI: 10.3969/j.issn.1006-1335.2014.04.012
    Abstract ( )   PDF (1188KB) ( )  
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    Experimental Research of Material Damping Performance of High-speed Train in Low Temperature Environment
    2014, 34(4): 56-61.  DOI: 10.3969/j.issn.1006-1335.2014.04.013
    Abstract ( )   PDF (1536KB) ( )  
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    Effects of Different Forms of Damping on Vibration and Sound Radiation Characteristics of Wheels
    2014, 34(4): 62-66.  DOI: 10.3969/j.issn.1006-1335.2014.04.014
    Abstract ( )   PDF (1426KB) ( )  
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    Linear Spectra Reduction of Flexible Base Vibration Isolation System Based on Chaotification Method
    2014, 34(4): 67-70.  DOI: 10.3969/j.issn.1006-1335.2014.04.015
    Abstract ( )   PDF (1269KB) ( )  

    Line spectra in the radiated noise of marine vessels are the most visible signs, which can be detected, tracked and identified by enemy’s passive sonar, and hence it is of great significance to reduce the line spectra for improving the acoustic stealth of marine vessels. In this paper, a anticontrol of chaos method based on chaotification is prososed for a vibration isolation system (VIS) of on board machinery to make the chaotic motion in nonlinear VIS persistent. In this way, the line spectra in the radiated noise can be reduced effectively because the response spectrum of a chaotic system under harmonic excitations is a continuous and reduced one. Numerical simulations are carried out and the results confirm the effectiveness of this method.

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    Influence of Fluid Loading on the Damping Loss Factor of Underwater Unconstrained Damping Plates
    2014, 34(4): 71-76.  DOI: 10.3969/j.issn.1006-1335.2014.04.016
    Abstract ( )   PDF (1303KB) ( )  

    Firstly, spectral finite element method is developed for calculating structure loss factor of unconstraint damping plate considering fluid loading and the relationship between the radiation loss factor and power conversion efficiency is explored. Then, structure loss factor of unconstraint damping plate considering fluid loading is compared with the case un-considering fluid loading using spectral finite element method; the results are verified using the energy method. Finally, power conversion efficiency for the unconstraint damping plate underwater is calculated using three-dimensional elastic model; change law of power conversion efficiency with the variation of the damping layer’s Young's modulus, the damping layer’s thickness and the damping layer’s material loss factor is discussed. The study shows: within the frequency band that is less than the second-order flexural wave’s start frequency, structure loss factor of unconstraint damping plate with no fluid loading is less than the case with fluid loading; from the perspective of the frequency average, the power conversion efficiency becomes larger as the damping layer’s Young’s modulus becomes larger,becomes smaller as the damping layer’s thickness becomes larger and becomes smaller as the damping layer’s material loss factor becomes larger; there are large peaks in the power conversion efficiency in the low frequency, more gentle changes in the high-frequency and smaller values; actual submarine’s radiation loss factor may be negligible most of the time, and thus the fluid loading changes the damping loss factor mainly by changing the structure loss factor.

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    Simplification of Fluid Force in Rotordynamic Model of Centrifugal Pumps
    2014, 34(4): 77-82.  DOI: 10.3969/j.issn.1006-1335.2014.04.017
    Abstract ( )   PDF (1571KB) ( )  

    Researches on hydro force on impeller are significant for improving accuracy of computation on centrifugal pump vibration incited by fluid. A workbench of centrifugal pump rotor and antifriction bearing is firstly configed by installing vibration isolator on pump base, mounting corrugated pipe at pump import and export, and using electromagnetic coupling between motor shaft and pump shaft. Then a rotor dynamic model including four discs, three shaft sections and pump base is built for the workbench based on D'Alembert principle. And validation of the rotor dynamic model is also carried out by comparing base vibration from measurement with that from rotor-model transient response anlysis result, which is gained by Newmark- implicit algorithm and takes impeller concentrated fluid force as well as torque by CFD as incitation. At last, the fluid force on impeller is simplified to 20% fluid quality in impeller, 40% fluid quality in impeller, and concentrated force as well as torque by CFD respectively, compares among base vibrations by same Sine force on one disc in the model when the three simplifications are implemented for transient analysis respectively are also finished. The result shows that, the base vibration incited by fluid force during centrifugal pump operation can be effectively gained by simplifying fluid force on impeller to concentrated force and torque, and the amplitudes of base vibration acceleration and displacement by simplifying fluid force to concentrated force and torque are much larger than those by simplifying fluid force to 20% and 40% fluid weight in impeller respectively. Also, the acceleration and displacement amplitudes by 40% fluid weight in impeller are larger than those by 20% fluid weight in impeller. The rotor dynamic model built in this essay is effecive and reliable, and the workbench is feasible for validating and comparing accuracies of different simplifycations of fluid force.

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    Application of Tunable Vibration Absorber to Satellite’s Flywheels Based on Mechanical Tuning Technology
    2014, 34(4): 83-87.  DOI: 10.3969/j.issn.1006-1335.2014.04.018
    Abstract ( )   PDF (1490KB) ( )  

    In order to widen dynamic vibration absorber’s bandwidth, so that it can meet satellite flywheel vibration controlling’s request, a new kind of tunable dynamic vibration absorber based on mechanical tuning technology was presented. Its working principle was briefly introduced. Both theory analysis and experimental study show that mechanical tuning device greatly widen dynamic vibration absorber’s bandwidth to about 20Hz. This research of tunable dynamic vibration absorbing technology pointed out a new way for satellite flywheel vibration control.

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    Effect of Resilient Mounting on Vibration Performance of Rotor-bearing System in Rotating Machines
    2014, 34(4): 88-91.  DOI: 10.3969/j.issn.1006-1335.2014.04.019
    Abstract ( )   PDF (1036KB) ( )  

    Vibration characteristic of shafting-resilient isolation system is numerically studied based on nonlinear oil film force model and finite element method. The results show that employment of resilient mounting cause notable increase of shaft vibration, while vibration transmission to foundation is reduced. Influences of resilient mounting should be considered in design of shafting design to ensure shaft vibration in practical working condition. Suggestions on rotor-bearing system design are presented.

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    Study on nonlinear dynamics characteristics of rotor-bearing-seal system
    2014, 34(4): 92-95.  DOI: 10.3969/j.issn.1006-1335.2014.04.020
    Abstract ( )   PDF (1244KB) ( )  

    It uses numerical method to study the effect of rotor speed on rotor-bearing-seal system dynamics characteristics. It has simulated time domain diagram, orbit of rotor center, Poincare diagram and spectrum of frequency. It has studied that there are periodic motion, period-doubling motion and quasi-periodic motion in coupled rotor-bearing-seal system.

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    Finite Element Analysis of Sound Transmission through Unidirectionally Reinforced Sandwich Plates
    2014, 34(4): 96-100.  DOI: 10.3969/j.issn.1006-1335.2014.04.021
    Abstract ( )   PDF (1546KB) ( )  

    This paper presents a finite element (FE) analysis of sound transmission (ST) through sandwich plates with typical corrugated cores. The aim is to examine the reasonability of acoustically-transparent core assumption adopted in ST modeling of unidirectional sandwich plates for calculation of their sound transmission loss (STL). Two different FE models are respectively created in ABAQUS for the purpose: one is with acoustically-transparent core elements; another considers the structural-acoustic couplings between the core elements and the fluid inside the enclosed cavities. STL computations are performed for the cases where the sandwich plates are fabricated with, respectively, rectangular and trapezoidal core, and also with different acoustical media inside the cavities in-between the two face plates. The obtained results indicate that more accurate prediction of vibro-acoustic responses can be achieved when considering the structural-acoustic couplings between the core elements and the fluid inside the enclosed cavities in modeling the vibration response of and sound transmission through metallic sandwich plates.

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    Chaotic Signal Denoising Based on Optimal Threshold of Volterra and Wavelet Transforms
    2014, 34(4): 101-103.  DOI: 10.3969/j.issn.1006-1335.2014.04.022
    Abstract ( )   PDF (909KB) ( )  

    How to determine the optimal threshold of chaotic signal based on wavelet transform is an important topic in chaotic identification. In order to solve this problem, a method of choosing optimal threshold based on Volterra and wavelet transform was proposed. The chaotic signal was decomposed by wavelet transform. Then a floating parameter was set to regulate the threshold of wavelet signal on different scales according to the chaotic time series prediction error which is from the Volterra adaptive filers. Denoising for Chaotic time series generated by Lorenz system was simulated to compare with other methods, and the results showed that the proposed method was effective.

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    Distinguishing the Vibration Signal’s Periodicity of Vehicle’s Suspension System Based on Chaotic Parameters
    2014, 34(4): 104-108.  DOI: 10.3969/j.issn.1006-1335.2014.04.023
    Abstract ( )   PDF (1200KB) ( )  

    Distinguishing the vibration signal’s periodicity of vehicle suspension system based on the Chaos parameters

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    Experimental Study on Static and Dynamics Characteristic of a New Combined Slab Track System
    2014, 34(4): 109-114.  DOI: 10.3969/j.issn.1006-1335.2014.04.024
    Abstract ( )   PDF (1748KB) ( )  

       This paper presents a new type of high performance, low vibration combined slab track system and the evaluation method on vibration reduction. The new track system is optimized with resilient base plates on floating slab panel using continuous elastic mat. Dynamic excitation can be applied using exciter over the pre-loading. Track deflection, vibration can be measured at different positions to demonstrate the vibration performance with different track structures. Results obtained from this process can be compared with those found where installations of particular configurations tested have been installed in the track and measured. This study describes the testing methods used to investigate static and dynamic behavior of the new system. The deflection of rails and slab components of the new type of track system under heavy loads are studied. Static tests results are also compared with theoretical analysis and the results agree well. To investigate the vibration reduction performance, the dynamic hammer excitation tests are also carried to the system under loaded conditions between 14 tones and 16 tones. The tests show that the vibration level reduction can reach 25dB in the frequency range of 20Hz to 200Hz.

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    Algorithm for Modification of Measurement Data for Sound Transmission Loss of Acoustical Materials in Standing-wave Pipes
    2014, 34(4): 115-118.  DOI: 10.3969/j.issn.1006-1335.2014.04.025
    Abstract ( )   PDF (1010KB) ( )  

    Based on the four-microphone method in the standing-wave pipe, the effect of the multi-transmitted-reflected waves in the transmission pipe on the sound transmission performace have been discussed, and the modified formula which are associated with multi-transmitted-reflected waves have been derived. By measuring several circular samples in the standing-wave pipe, the differences between the multi-transmitted-reflected modification and the first transmitted-reflected modification have been compared. Experimental results show that: if the sound absorption performance of the acoustical termination is perfect, only the first transmitted-reflected modification is enough to obtain the sound transmission loss; while the sound absorption performance of the termination is not perfect as expected, the multi-transmitted-reflected modification should be taken into account.

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    Control Law Identification of Active Structures
    2014, 34(4): 119-122.  DOI: 10.3969/j.issn.1006-1335.2014.04.026
    Abstract ( )   PDF (927KB) ( )  

    Active structures can be found in several engineering contexts, including vibroacoustics, rotordynamics, or active control. For a variety of active structures, the control law is the key parameter which can reflect the dynamic characteristics of active structures. The control law of active structure is discussed in this paper. A formula which can be used to identify the type of feedback signal and its gain value is obtained conditionally. The method is constructed by the frequency response function(FRF) directly, avoiding the fitting of FRF curve, the inversion of FRF matrix and reconstruction for mass, stiffness and damping matrix of system. In addition, the simple expression of identification method is good for engineering application. A simulated academic test case supports the validity of the method.

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    Fast Multipole Method Applied in Prediction of Aeroacoustics Induced by a Circular Cylinder
    2014, 34(4): 123-127.  DOI: 10.3969/j.issn.1006-1335.2014.04.027
    Abstract ( )   PDF (1543KB) ( )  

    Prediction of aeroacoustics using acoustic analogy is a time-consuming process, while the fast multipole method which changes traditional way of node-to-node computing into set-to-set interaction can accelerate it effectively. The FW-H equation and its integral kernel function are derived with fast multipole method, which is based on the partial-wave expansion formulation of free space Green’s function. The unsteady flow field of two-dimensional circular cylinder is computed and exported as sound source, and the sound field is obtained via traditional method and the fast multipole method. The results show that fast multipole method based on partial-wave expansion can calculate the aerodynamic noise accurately while reduce the computing time sharply at relatively low frequencies, and the acceleration effect is more obvious with larger number of observers.

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    Study on Measurement Method of Bearing Stiffness without Disassembling
    2014, 34(4): 128-133.  DOI: 10.3969/j.issn.1006-1335.2014.04.028
    Abstract ( )   PDF (1502KB) ( )  

    Bearing stiffness influences shaft vibration significantly, and researches on the mesurement method without disassembly is good for obtaining shaft vibration fastly and reliablely. Workbench of centrifugal pump rotor and antifriction bearing is firstly configed by installing vibration isolator on brace, mounting corrugated pipe at pump import and export, and using electromagnetic coupling between motor shaft and pump shaft. Also, photoelectric sensor is installed as shaft phase reference, and phase angles of equivalent eccentric weights on shaft sections near bearings are indentified by vibration-displacement peaks. Then excitation forces are generated by adding masses on shaft at the phase angles respectively, and variations of vibration-displacement peaks as well as bearing stiffnesses are tested by virtual instrument built by LabVIEW. At last, the stiffnesses are validated by actual workbench configuration and rotor model. The result shows that, the bearing stiffness test method without disassembling is feasibale, and the workbench is reliable to validate the method. Taking photoelectric sensor for shaft phase reference is effective for measurement of equivalent eccentric weights phase and installation of additional mass, and the virtual instrument can also accurately calculate the equivalent eccentric weights phase of shaft and support stiffness of bearing.

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    Research of Fluid Excitation of Axial Flow Pump under Different Working Conditions
    2014, 34(4): 134-137.  DOI: 10.3969/j.issn.1006-1335.2014.04.029
    Abstract ( )   PDF (1508KB) ( )  
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    Isolation Effect of the System with Equipment Support’s Flexibility
    2014, 34(4): 138-141.  DOI: 10.3969/j.issn.1006-1335.2014.04.030
    Abstract ( )   PDF (1013KB) ( )  

    Based on the flexible characteristic of the equipment in high frequency, a model is established which regard the equipment support with elastic properties as a free-free continuum system, and the source output a constant force in the equipment support which has rigid motion and elastic vibration. Then the characteristics of the flexible equipment support and power flow to vibration system is studied utilizing mobility matrix method. It is shown that the position of the source excitation has a great influence to isolation performance. The pitch oscillation of the system and the even order modes of the support and base will be inspired when the source excitation point don't match with the midpoint of the equipment support, all this result in deterioration of isolation performance. The even order modes of the base will be inspired if the isolators non-symmetrical arrangement to the midpoint of the equipment support or base, and the former situation can also lead to axial and pitch coupled oscillation, but the even order modes of the equipment support will not be inspired.

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    Experiment and Design of Annular Mass-tunable Dampers Based on Particle Collision Principle
    2014, 34(4): 142-147.  DOI: 10.3969/j.issn.1006-1335.2014.04.031
    Abstract ( )   PDF (1279KB) ( )  

    Buffer tank, pipeline, pressure vessels, heat exchangers and other cylindrical chemical equipment usually vibrate severely in petrochemical enterprises. The vibration control mechanism of such continuous structure with tuned mass damper was studied by adopting the idea of low element model and equivalent mass identification. A new type particle collision ring tuned mass damper was proposed which is mounted easily. Radial composite stiffness of symmetrical arrangement spring was calculated based on the numerical analysis and damping coefficient of particles collision was measured for achieving the optimal tuning parameters of damper. The vibration control features was simulated by MATLAB. The vibration test bench of cantilever steel structure cylinder was established for verifies the performance of damper at the first modal natural frequency. The results show that particle collision ring tuned mass damper can suppress structural vibration effectively in all directions and has a wide range of frequency band. The particle collision damping and ring design can provide greater application space for tuned mass damper.

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    Modal Analysis Test of a Two-unequal-span Continuous Beam
    2014, 34(4): 148-152.  DOI: 10.3969/j.issn.1006-1335.2014.04.032
    Abstract ( )   PDF (1402KB) ( )  

    Abstract: Introduce that the influence of two-unequal-span continuous beam on vibration mode, and discuss the value of impact factor. The channeled beam was used as a model of continuous beam. The finite element analysis software Midas and the DASP equipment were respectively used for modal analysis to obtain the first three vibration modes and frequencies of the continuous beam on different span ratio. Compared two results, and confirmed the authenticity of the vibration mode change. The results demonstrate that (1) with the span ratio decrease, the vibration mode turned and the curvature of vibration mode change; (2) when considering the effect of positive bending moment at midspan, the fundamental frequency should be used as shown in the General Code to calculate the impact factor; (3) when considering the effect of negative bending moment at middle fulcrum, the 2nd or 3rd frequency should be used to calculate the impact factor.

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    Vibration and Impact Control of Crane’s Slewing Gears
    2014, 34(4): 153-156.  DOI: 10.3969/j.issn.1006-1335.2014.04.033
    Abstract ( )   PDF (1285KB) ( )  

    In order to find out the failure mechanism of slewing gear of crane, an dynamics model of a set mating gears with damping under the emergency braking was established. A fine finite element model was set up to investigate the dynamic response properties of the gears considering the huge inertia of the slewing part and the gap between the mating gears, and anti-shock effect due to different kinds of damping was discussed by using the explicit dynamics FEA analysis method .The results showed that damping can effectively suppress vibration and impact load of the slewing mating gears and the non-viscous fluid damping was illustrated to have better results.

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    Research of Optimal Algorithm for Noise Signal Separation
    2014, 34(4): 157-160.  DOI: 10.3969/j.issn.1006-1335.2014.04.034
    Abstract ( )   PDF (1174KB) ( )  

    Noise is one of the biggest barrier in vibration signal processing for mechanical system. A novel FastICA algorithm, conjugate gradient algorithm, is presented in this paper, which is based on independent component analysis (ICA). The proposed method has advantages in terms of convergence and robust. The experimental analysis results investigate the effectiveness of the proposed method in vibration signal separation.

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    Parameter Matching Design for Clutch System of an Electromagnetic Fan
    2014, 34(4): 161-164.  DOI: 10.3969/j.issn.1006-1335.2014.04.035
    Abstract ( )   PDF (1204KB) ( )  

    Abstract:Analysing the electromagnetic fan clutch system vibration problem and impact factors, and the sensitivity was studied,the formulae of sensitivity were also worked out.Then the parameter matching design method and technical route for electromagnetic fan clutch system were presented,a typical electromagnetic fan clutch system has been matched and designed by this method.Research showed that the parameter matching design can not only solve the excessive vibration problem of the system,but also can ensure that the structure has a good flexibility and a smaller mass,achieving a very good result.

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     Reliability Analysis of Suspension Device in the Refit of a Tracked Vehicle
    2014, 34(4): 165-168.  DOI: 10.3969/j.issn.1006-1335.2014.04.036
    Abstract ( )   PDF (1128KB) ( )  
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     Optimization and Experimental Verification of Vibration Characteristics for a Light Bus Exhaust System
    2014, 34(4): 169-173.  DOI: 10.3969/j.issn.1006-1335.2014.04.037
    Abstract ( )   PDF (1515KB) ( )  

    In order to improve the ride comfort of a domestic light bus, reduce the abnormal larger vibration of the body floor at Exhaust System side, the road test was carried out and compared with those of the competitive bus. The test results showed that the hanger locations layout and stiffness of the Exhaust System are unreasonable, causing the vibration of the vehicle body transferred from the Exhaust System is excessively large. the average driving DOF(ADDOFD) is applied to analysis, then summation of ADDOFD displacement response of reference points was calculated in range of all the modal-shapes, an optimized hanger locations layout was obtained on the basis of the minimum of the summation of ADDOFD displacement response; the hanger stiffness was optimized through comprehensive consideration of the vibration isolation and fatigue resistance characteristics. The optimal scheme was designed and test analysis was performed based on the optimization of the hanger locations layout and stiffness. Comparing the test results before and after optimization, the effectiveness and rationality of the optimization were verified.

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    Interior Sound Field Simulation and Sound Quality Optimization   of Metro Vehicles
    2014, 34(4): 174-177.  DOI: 10.3969/j.issn.1006-1335.2014.04.038
    Abstract ( )   PDF (1067KB) ( )  

    Abstract: The interior noise of Shanghai rail transit line nine was measured on site. The finite element model of the carriage was established based on the structural parameters, and then Actran software was used for acoustical simulation. The accuracy of the simulation results were verified by using two major objective evaluation parameters of sound quality: A-weighted sound pressure level (SPL) and specific loudness. A sound quality optimization scheme was put forward and performed, which obtained a sound quality improvement with 5 dB decrease in SPL and 1.26 sone reduction in loudness. The proposed scheme is effective for improving interior acoustic environment and has certain significance for improving the sound quality.

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    Analyses of Subway Induced Environment Vibration and Vibration Reduction of Rail Track Structure
    2014, 34(4): 178-183.  DOI: 10.3969/j.issn.1006-1335.2014.04.039
    Abstract ( )   PDF (1684KB) ( )  

    Taking Nanchang Bayi square of the subway line 1 as the engineering background, the three-dimension finite element model of rail-tunnel-ground was constructed and dynamic responses were calculated. Three kinds of track bed model were constructed, monolithic track bed, elastic supporting block track bed and steel spring floating slab track bed. Taking vibration acceleration, one-third octave vibration acceleration level and Z vibration level as evaluation indexes, the vibration response of tunnel wall and ground surface was contrasted in different situations of track structure. Considering the support stiffness change of vibration reduction track bed, the influence of natural frequency to vibration reduction effect was analyzed. The study shows that main frequency of ground surface vibration induced by train is near 40Hz. The natural frequency of vibration for vibration reduction track bed has a great influence on the vibration reduction effect. Steel spring floating slab track bed is much better than elastic supporting block track bed on vibration reduction effect.

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    Research of Indoor Acoustic Environment of a New Tobacco Workshop in Shanghai Cigarette Factory
    2014, 34(4): 184-488.  DOI: 10.3969/j.issn.1006-1335.2014.04.040
    Abstract ( )   PDF (1940KB) ( )  

    Tobacco industry is undergoing renovation of green workshop, and acoustic environment is an important assessment indicator. Investigate and analyze on current acoustic environment including reverberation time and sound field characteristic in new-built tobacco workshop of Shanghai cigarette factory are done. Treatments on improvement of acoustic environment are proposed according to the theory of noise reduction due to sound absorption. Then, semi-quantitative theoretical analysis of effect by plant units themselves on noise reduction is made. Finally, noise distribution of a newly tobacco workshop was predicted by computer simulation. The semi-quantitative theoretical analysis, computer simulation and measurements on acoustic environment of the workshop show that the application of noise reduction due to sound absorption both reliable and valid.

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    Numerical Simulation of Noise Emission of Wind Turbines
    2014, 34(4): 189-191.  DOI: 10.3969/j.issn.1006-1335.2014.04.041
    Abstract ( )   PDF (1163KB) ( )  

    With the vigorous development of wind energy technology, the environmental impact of wind turbines attracts more and more attention. This paper discusses the problem of wind turbine noise propagation, and the mathematical relationship between noise value and distance is derived. Noise recipients are generally located on the ground, in this paper, the distance from the receiver to tower as the independent variable, the characteristics of noise propagation are discovered. Finally, the results of mathematical derivation were compared with the simulation results with the commercial noise propagation software, and this comparison showed good consistency.

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     Measurement and Analysis of Objective Parameters of Sound Quality for a Diesel Engine
    2014, 34(4): 192-196.  DOI: 10.3969/j.issn.1006-1335.2014.04.042
    Abstract ( )   PDF (1610KB) ( )  

    Abstract: The noise of the diesel engine at different speed and load has been tested and analyzed the four objective evaluation parameters of noise: loudness, sharpness, roughness and fluctuation strength .The results show that spec. loudness curve can be determined accurately reflect the human auditory experience for the change of sound frequency components ;as the increase of speed and load ,the degree of loudness and sharpness showed a significantly increasing trend ;while in the rang of 900r/min~1700r/min ,fluctuation strength showed a significant decreasing trend.

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    Analysis of Sound Insulation Performances of Single and Double Layer Glazing Windows Based on SEA
    2014, 34(4): 197-201.  DOI: 10.3969/j.issn.1006-1335.2014.04.043
    Abstract ( )   PDF (1196KB) ( )  

    The basic principle of statistical energy analysis (SEA) was expounded, and the relevant parameters, motion equations and expressions of power balance equations were provided in this paper. The sound insulation models of single and double glazing windows with the same thickness were built, and the sound insulation performance were analyzed based on SEA. The results showed that, within the frequency range of 125~4000Hz, the errors of sound transmission loss between the predicted and the measured data of insulation models were within 3dB and 7dB respectively (except in critical frequency). The analysis also showed that sound transmission loss of double glazing window with sound absorption treatment at its frames was 13dB higher than that of single glazing window. Within the range of 500~4000Hz, the sound insulation of double glazing window would improve 1dB as the thickness of air layer increased 50mm.

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    Noise Control of a High Power Electric Motor
    2014, 34(4): 202-204.  DOI: 10.3969/j.issn.1006-1335.2014.04.044
    Abstract ( )   PDF (1074KB) ( )  

    In this paper, a noise control of a typical high power electric Motor motor is solved. Based on the measuring and analyzing the characters, contribution and transfer path of noise sources and the motor structural constraint, the noise control is designed with the development of acoustic materials. The overall sound level decreases 8 dB , which effectively improve the motor’s competitiveness.

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    Dynamic Response Analysis of Wind Turbine Towers under Wind and Earthquake Combined Loadings
    2014, 34(4): 205-208.  DOI: 10.3969/j.issn.1006-1335.2014.04.045
    Abstract ( )   PDF (1052KB) ( )  

    In order to obtain the dynamic response of horizontal axis wind turbine tower under combined wind and earthquake effects, the dynamic equation of tower was established for the wind loads and earthquake which were analyzed in detail. Then dynamic response of a 3.0MW wind turbine tower was calculated, the top vibration deflections and bottom loads of tower was obtained, The simulation results indicate that the earthquake obviously affects the dynamic response of wind turbine tower.

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    Finite Element Analysis of Elastic Support Performance of Wind Turbines
    2014, 34(4): 209-213.  DOI: 10.3969/j.issn.1006-1335.2014.04.046
    Abstract ( )   PDF (1434KB) ( )  

    The obvious nonlinear mechanical properties of rubber directly affected the function of elastic support of wind turbine to reduce vibration.The experimental data got by rubber tension and compression experiment was fitted by a finite element analysis software, and an optimal rubber constitutive model was derived. Based on the condition of actual use, reasonable working parameters and material parameters were selected to establish a whole model, a quarter model and an axisymmetric model for elastic support of wind turbine.Then the three models were calculated and the results were compared carefully. The quarter model was selected to analyze the performances of elastic support, such as nonlinear vertical stiffness, lateral stiffness and natural frequency and so on. The experimental results showed that the finite element analysis was effective. The work was quite meaningful for design of new elastic support of wind turbine.

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     Effect of Rail Vibration Absorbers on Vertical Vibration of Elevated Structures
    2014, 34(4): 214-218.  DOI: 10.3969/j.issn.1006-1335.2014.04.047
    Abstract ( )   PDF (1302KB) ( )  
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    Relationship between Harmonic Wave of Power Supply and Noise Vibration of Air Conditioners
    2014, 34(4): 219-222.  DOI: 10.3969/j.issn.1006-1335.2014.04.048
    Abstract ( )   PDF (924KB) ( )  

    Introduced the power harmonic-interharmonic and its calculation,researched the impact of odd harmonic-interharmonic and the noise vibration of the air conditioner by two specific cases respectively.

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    Smelting Noise Control of a 100-ton Electric Furnace
    2014, 34(4): 223-227.  DOI: 10.3969/j.issn.1006-1335.2014.04.049
    Abstract ( )   PDF (1050KB) ( )  

    In this paper, the noise control within a domestic electric furnace workshop was introduced. An advanced noise control technology from aboard was applied in this workshop, however, the actual noise value cannot meet the design requirements, and exceeds the national standard. The distribution of the noise which meets the design requirements, namely the designed noise value, has been systematically investigated. Then, compared to the actual distribution of the noise, based on the analysis of possible problems in the construction process, the effective measures of noise control for electric furnace steelmaking workshop were summarized.

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