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18 October 2018, Volume 38 Issue 5 Previous Issue    Next Issue

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TheInternationalChallengefromNoiseLimitValuesfor ChineseTruckProducts 2018, 38(5): 1-6.  DOI: 10.3969/j.issn.1006-1355.2018.05.001 Abstract ( )   PDF (1123KB) ( )   The UN ECE has set different limit values for the five sub-categories of N2、N3 category trucks in ECE R51-03, according to different rated engine power. Compared with European trucks, the Chinese products always have a higher gross vehicle mass, more axles and lower engine power, and there is less contact between the rated engine power and noise test results in China. The sub-category method of ECE R51-03 based on rated engine power will lead to more strict limit values for Chinese trucks and the technical barriers have been built up for Chinese trucks export type approval. With the research of proof test data in China, this paper suggests a new sub-category method for Chinese trucks which is based on the gross vehicle mass and axles numbers, and provides the possible solutions for Chinese trucks to fulfill the limit values of ECE R51-03. Related Articles | Metrics

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Dynamic Modeling and Analysis of Underwater Launch Systems with Buffer Devices under Transient Loads 2018, 38(5): 7-11.  DOI: 10.3969/j.issn.1006-1355.2018.05.002 Abstract ( )   PDF (2178KB) ( )   Related Articles | Metrics

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Study on the Method of Transfer Path Recognition of Ship Transient Noise Excitation Sources 2018, 38(5): 12-20.  DOI: 10.3969/j.issn.1006-1355.2018.05.003 Abstract ( )   PDF (3791KB) ( )   Related Articles | Metrics

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Vibration Characteristic Analysis of Rectangular Thin Plates based on Improved Fourier Series Method 2018, 38(5): 21-26.  DOI: 10.3969/j.issn.1006-1355.2018.05.004 Abstract ( )   PDF (1707KB) ( )   Abstract: Based on the theory of Improved Fourier Series Method (IFSM), the vibration characteristic of rectangular thin plate with arbitrary boundary condition is studied. Besides, sine function term is introduced to modify the discontinuity of boundary condition. What’s more, through changing the values of the restraint stiffness k and the rotational restraint stiffness K, arbitrary boundary conditions can be simulated. Therefore, defects of the ordinary method dealing with structure vibration that could only be solved under some simplified boundary conditions have been overcome. The effectiveness of this method has been verified by comparing with the results of Literature and FEM software. Based on large amount of calculation, we found natural frequency differs greatly in varied boundary conditions. Besides, natural frequency of rectangular thin plate decreases with the growth of aspect ratio. Related Articles | Metrics

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Study on Commutation Sensitivity of Electromagnetic Directional Valves under Base Vibration li wei 2018, 38(5): 27-33.  DOI: 10.3969/j.issn.1006-1355.2018.05.005 Abstract ( )   PDF (2307KB) ( )   Related Articles | Metrics

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Flow-induced Vibro-acoustic Coupling Response Analysis of Pump Jet Thrusters 2018, 38(5): 34-39.  DOI: 10.3969/j.issn.1006-1355.2018.05.006 Abstract ( )   PDF (2746KB) ( )   The pump jet thruster, which is composed of the duct, rotors and stators, helps improve the propulsion efficiency of an underwater ship, yet excessive vibrations would occur due to hydraulic excitations, and the radiated noise will weaken the acoustic stealth performance of the ships. In order to understand the dynamic characteristics of pump jet thruster under fluid excitation, a computational fluid dynamics (CFD) with large eddy simulation (LES) is conducted in this paper firstly, and the fluctuating pressure on the interior surface of the duct is obtained, which is transformed into structural excitations; then, a coupled finite element/boundary element model (FEM/BEM), which consists of the duct and the surrounding water, is established. Based on this model, the vibration displacement of the duct and radiated sound pressure field under the structural excitations are calculated and analyzed. Moreover, the influences of the advanced coefficient on the hydrodynamic properties and vibro-acoustic responses are also presented. The simulations in this paper provide a guideline for the vibration and noise reduction design of the propellers with a similar structure in engineering. Related Articles | Metrics

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Band Gap Analysis for Periodically Supported Structures based on Substructure Synthesis Method SONG Hanwen 2018, 38(5): 40-44.  DOI: 10.3969/j.issn.1006-1355.2018.05.007 Abstract ( )   PDF (1412KB) ( )   Periodic structures are special for the ‘filter’ characteristic. In some frequency band which called band gap, vibration is inhibited. Band gap for simple periodically supported system was also studied, while periodic support used to establish as boundary between cells. Considering the complicated support system in practice, a novel model for periodically supported structure was developed based on substructure synthesis with FRF data and the band gap phenomenon was discussed. Floquet’s theorem was applied to describe the periodicity and Transfer matrix methods was used to obtain the band gap. Due the ill-condition problem existing in numerical transfer matrix method, FRF expressions with modal parameters were introduced to build the transfer matrix. Modal truncation was practiced remaining only the main orders. The relationship between modal parameters and band gap is discussed to help reversal designing and optimization. Related Articles | Metrics

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Research on Structural Vibration Transfer Path Analyses using Different Load Identification Methods 2018, 38(5): 45-51.  DOI: 10.3969/j.issn.1006-1355.2018.05.008 Abstract ( )   PDF (1437KB) ( )   To improve the validity and engineering practicability of transfer path analysis method which was used to analyze the vibration transfer characteristics, a novel matrix inverse method (MIM) for identifying load, regardless of the noise sources were removed or retained, was proposed. And then the new method is in-depth comparison with the classical load identification methods such as the complex stiffness method and its parametric model. Thus, the three corresponding TPA methods were also established. Based on the examples of vibration model, the performance of three TPA methods and the influence of structural parameters on the performance of TPA method are deeply analyzed systematically. The results show that the new MIM-TPA method has better accuracy and stability in structural vibration transfer characteristics analysis. Moreover, the accuracy, efficiency and applied scope of several algorithms are also determined. Related Articles | Metrics

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Modal Analysis and Structure Optimization of the Rotors of Forage Rubbing and Breaking Machines 2018, 38(5): 52-56.  DOI: 10.3969/j.issn.1006-1355.2018.05.009 Abstract ( )   PDF (1725KB) ( )   Related Articles | Metrics

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CFxLMS Algorithm with Variable Step Size and its Application to Simulation of Elevator Cabin Noise Active Control 2018, 38(5): 57-61.  DOI: 10.3969/j.issn.1006-1355.2018.05.010 Abstract ( )   PDF (1517KB) ( )   A modified CFxLMS(Correlation FxLMS) algorithm is proposed in this paper, which makes use of the correlation function of the filtered reference-error signal to control the step size update. The step size decreases along with the decrease of the correlation function, thereby improves algorithm real-time capability, and performs better to overcome the inherent contradiction of the FxLMS algorithm between convergence speed and stable error. For further verification, the CFxLMS algorithm is applied in high speed elevator cabin active noise control. Simulation results are also compared with the results of the FxLMS algorithm. Related Articles | Metrics

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Study on the Rub-impact Behaviour of a Rotor System with Stoppers 2018, 38(5): 62-65.  DOI: 10.3969/j.issn.1006-1355.2018.05.011 Abstract ( )   PDF (1560KB) ( )   Related Articles | Metrics

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The Chebyshev Polynomial Approximation of Vibro-impact System Motion Solution under Stochastic Disturbances 2018, 38(5): 66-70.  DOI: 10.3969/j.issn.1006-1355.2018.05.012 Abstract ( )   PDF (2000KB) ( )   A three degree of freedom vibro-impact system is established according to the hydraulic impact breaker. The system perturbation solution is approximated by the second Chebyshev polynomial. Under the different disturbance intensities, the approximation properties between approximated solutions and perturbation solutions are analyzed by the numerical simulation. The results show that the system approximated by the second Chebyshev polynomial presents good approximating characteristics under some small degree of disturbance intensity, and there are variety of forms of the evolutions from periodic motion to chaos, such as the periodic doubling bifurcation, the loss of sequence in inverse periodic doubling bifurcation, Hopf bifurcation and torus doubling bifurcation, phase lock. Related Articles | Metrics

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Shock Characteristics of Vulnerable Components of Suspension System under Rectangular Pulse Excitation CHEN An-Jun 2018, 38(5): 71-74.  DOI: 10.3969/j.issn.1006-1355.2018.05.013 Abstract ( )   PDF (1612KB) ( )   Related Articles | Metrics

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A Fast Prediction Method for Underwater Radiation Noise from Ships 2018, 38(5): 75-80.  DOI: 10.3969/j.issn.1006-1355.2018.05.014 Abstract ( )   PDF (2747KB) ( )   Related Articles | Metrics

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Adaptive Backstepping Control of Propeller induced Vibration of Ship Systems with Parameter Uncertainties Alex XinGong 2018, 38(5): 81-88.  DOI: 10.3969/j.issn.1006-1355.2018.05.015 Abstract ( )   PDF (1954KB) ( )   Related Articles | Metrics

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Noise Separation Prediction ofWater Injection Pipeline Systems ofWarships based on BEM/FEM 2018, 38(5): 89-93.  DOI: 10.3969/j.issn.1006-1355.2018.05.016 Abstract ( )   PDF (1597KB) ( )   Related Articles | Metrics

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A Planar Motor Driven by an X-shaped Piezoelectric Vibrator 2018, 38(5): 94-99.  DOI: 10.3969/j.issn.1006-1355.2018.05.017 Abstract ( )   PDF (2207KB) ( )   Related Articles | Metrics

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Analysis of Nonlinear Vibration Characteristics of Automobiles Passing through Deceleration Zones 2018, 38(5): 100-106.  DOI: 10.3969/j.issn.1006-1355.2018.05.018 Abstract ( )   PDF (2278KB) ( )   Based on 7-DOF linear system, this paper established the mechanical model of whole vehicle which takes the nonlinearity of suspension spring, damping and tire into consideration. The continuous speed humps on the highway pavement was chosen as an excitation. By the analysis of mechanical model and the Lagrange method, differential equation of this system is derived. By using MATLAB, we obtain the bifurcation diagrams of nonlinear damping coefficient and excitation frequency. These two diagrams show that complex nonlinear vibration occurs within a certain range. Time history diagram, phase diagram, Poincare cross section and PSP peak graph are plotted to study the complex nonlinear behavior. Effect of nonlinear damping coefficient and excitation frequency on the system is also studied in this paper. Finally, in terms of varying velocity, vibration of vehicle when passing the continuous speed humps is shown by means of fitting the instantaneous velocity in terms of varying velocity. Related Articles | Metrics

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Experimental Research on Noise Source Characteristics of EMU6 Train’s External Pantographs 2018, 38(5): 107-112.  DOI: 10.3969/j.issn.1006-1355.2018.05.019 Abstract ( )   PDF (1881KB) ( )   Related Articles | Metrics

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Study on Effects of Stiffener Section Types on Sound Insulation of Railway Vehicle’s Panel Structures 2018, 38(5): 113-118.  DOI: 10.3969/j.issn.1006-1355.2018.05.020 Abstract ( )   PDF (1832KB) ( )   In view of the reduction of sound insulation performance due to the lightweight design of railway vehicles, the effect of different stiffener sections on the sound insulation enhancement is studied. The prediction model of sound insulation characteristics of stiffened plate for railway vehicles was built based on the hybrid method of finite element and statistical energy analysis (Hybrid FE-SEA), and the effects of stiffener sections on the sound insulation characteristics of the plate were systematically analyzed. The section types include T-type, L-type, I-type and rectangular type. The results show that the stiffness and the first natural frequency of the stiffened plate are larger than that of the homogeneous plate, and increase with the increase of stiffener thickness. When the stiffener thickness is constant, the stiffness and the first natural frequency of the T stiffened plate are the largest, and the L stiffened plate is second. Laying thickness of 15mm stiffener, the sound insulation performance of plate is the best. When the mass, thickness, web area and size, wing area of the stiffeners are equal, there is little difference in the weighted sound transmission loss of various types of stiffened plates. In addition, after the panel is reinforced, the sound insulation at the stiffness control zone is increased by 3~17 dB, and the sound insulation between 1250~4000 Hz frequency bands is increased by 1~6 dB. Comprehensive analysis indicates that taking weighted sound insulation is used as the evaluation standard, the thickness of stiffener is 15mm when the stiffener mass, web area, wing area and size are equal, and the sound insulation performance of the plate is the best, Rw is 1.4~1.5 dB higher than that of the homogeneous plate, and the stiffness of T-type and L-type stiffened plates is the best when the stiffener thickness is constant. The related research results can provide reinforced optimization design reference for plate of railway vehicles. Related Articles | Metrics

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Study on the Effect of Torsional Stiffness of Transmission Systems on the Abnormal Sound of Transmission Gears liang dachen 2018, 38(5): 119-122.  DOI: 10.3969/j.issn.1006-1355.2018.05.021 Abstract ( )   PDF (1605KB) ( )   Abstract: Taking the combination of experiment and subjective evaluation, the problem of gear knocking abnormality of Front—engine Rear—drive is studied, and the strong correlation between the torsional vibration characteristic of the driveline and the abnormal sound of the transmission gear is confirmed. The simulation model of the transmission system is established by using ADAMS software and the influence of the torsional stiffness characteristic parameters of the key components of the transmission system on the abnormal sound of the gears. The results show that the main damping rigidity of the clutch and the torsional stiffness of the rear axle have a significant effect on the torsional vibration of the transmission system, which causes the gears to hit the gears, which can be effective by reducing the main vibration, stiffness and increasing the axle stiffness Suppress such abnormalities. Related Articles | Metrics

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Rail Corrugation Control of the Track Sections in Nanjing Metro with GJ-32 Fasteners 2018, 38(5): 123-127.  DOI: 10.3969/j.issn.1006-1355.2018.05.022 Abstract ( )   PDF (1691KB) ( )   Related Articles | Metrics

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Optimization Design of Low-frequency Structures driven by Sound Quality based on Moore Loudness 2018, 38(5): 128-133.  DOI: 10.3969/j.issn.1006-1355.2018.05.023 Abstract ( )   PDF (2316KB) ( )   Related Articles | Metrics

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Effect of Bolt Connection on Structural Vibration Modes of Combustion Chambers 2018, 38(5): 134-138.  DOI: 10.3969/j.issn.1006-1355.2018.05.024 Abstract ( )   PDF (1702KB) ( )   Related Articles | Metrics

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Analysis of the Factors Affecting Noise Reduction of Near-rail Low-height Noise Barriers 2018, 38(5): 139-145.  DOI: 10.3969/j.issn.1006-1355.2018.05.025 Abstract ( )   PDF (1715KB) ( )   In order to quantitatively analyze the noise reduction characteristics and effects of near-rail low height noise barrier, the symmetrical point sound source simulates the wheel-rail sound source. Considering the spatial geometry and acoustic boundary characteristics of the vehicle body and the track structure, the acoustic boundary element method is used to establish the vehicle exterior noise prediction model, and the spatial sound field response under the sound barrier and sound absorption treatment is compared and analyzed. The results show that the insertion loss of 0.25 m high vertical no absorption sound barrier is -1.7 dBA at the standard evaluation point (7.5 m away from the track centerline, 1.2 m high from the track surface). If the height of sound barrier increases by 0.25 m, the insertion loss will increase by 0.4~2.9 dBA. If the sound absorber is added inside the barrier of the 1.0 m high vertical no absorption sound barrier, as well as the track structure, the insertion loss increases by 6.1 dBA. If the Y-head is added to the 1.0 m high vertical no absorption sound barrier, the insertion loss will increase by 2.7 dBA. The related research results can provide scientific guidance for urban rail transit vibration and noise reduction. Related Articles | Metrics

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Vibration Reduction Study and Parameter Optimization of Steel Spring Floating Slab Tracks in Metro Viaducts 2018, 38(5): 146-150.  DOI: 10.3969/j.issn.1006-1355.2018.05.026 Abstract ( )   PDF (2100KB) ( )   Abstract: To inquire into the steel spring stiffness and density of the floating slab of elevated steel spring floating slab track the influence law of vibration damping characteristics, by building the vehicle - train-bridge coupling model of floating slab track (FST), from the Angle of time and frequency domain analysis, for the design of the steel spring floating slab track parameters provide theoretical basis for the reasonable selection and combinatorial optimization. The results show that the vibration level of the floating plate increases with the decrease of the steel spring stiffness in the range of 2 ~ 20Hz. In the frequency range of 16 ~ 125Hz, the vibration level of the centerline, the flange, the web and the beam bottom of the track decreases with the decrease of the stiffness of the steel spring, and the maximum value is reduced to 13dB. The stiffness of the steel spring has obvious effect on the transfer function. The smaller the stiffness of the steel spring, the smaller the value of the vertical transfer function of the floating plate to the bridge structure. Considering steel spring stiffness change on the influence of bridge structure vibration level and the impact on the transfer function, in the design of floating slab track structure suggestion will steel spring stiffness control in 6 ×106 N/m ~ 8×106 N/m. The increase of the floating plate density will reduce the vibration level of the system to a certain extent. In actual design, the floating plate density should be reasonably set, and the proposed control should be controlled at 2800kg/m3 ~ 3200kg/m3. Related Articles | Metrics

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Acoustic Test and Analysis before and after the Reparation of the Grand Stage of the Dehe Yuan in the Summer Palace 2018, 38(5): 151-155.  DOI: 10.3969/j.issn.1006-1355.2018.05.027 Abstract ( )   PDF (1663KB) ( )   In order to promote the authenticity conservation of the acoustic field of the Grand Stage of the Garden of Virtuous Harmony, this paper measured the reverberation time, the impulse response and the unevenness of sound pressure level before and after the Garden of Virtuous Harmony were repaired. By comparison and analysis of data, it revealed the effect of closed porch and temporary stand, evaluated the effect of authenticity conservation of acoustic, provided a scientific evidence for the performing and watching behavior recorded by historical archives. Related Articles | Metrics

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Discussion on the Application of Two Foundation Isolation Measures in Buildings Receiving Excessive Vibration from Adjacent Subway Lines 2018, 38(5): 156-161.  DOI: 10.3969/j.issn.1006-1355.2018.05.028 Abstract ( )   PDF (2002KB) ( )   This paper discusses the feasibility of two foundation isolation methods, one being the elastic foundation mat, and the other being the spring support system, applied to mitigate the vibration level of a structure receives from nearby subway tracks. Fundamental mechanisms of the methods are firstly introduced, and a discussion on their practical engineering applications is followed. By taking a large construction project as a case study, the two measures are specifically designed to a building in the project and their isolation effect and cost is comparatively discussed. According to quantitative evaluation, both methods are expected to be effective as when applied the vibration in the superstructure is significantly mitigated, although there is difference in cost and influence on structural design. The conclusions can be a reference for future applications of the methods. Related Articles | Metrics

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Discussion of Optimal Design of Noise Absorption Technology for Transformer RoomWalls of Urban Indoor Substations 2018, 38(5): 162-166.  DOI: 10.3969/j.issn.1006-1355.2018.05.029 Abstract ( )   PDF (1641KB) ( )   Related Articles | Metrics

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A New Method and its Application for Fault Diagnosis of Gearboxes based on Improved EmpiricalWavelet Transform 2018, 38(5): 167-172.  DOI: 10.3969/j.issn.1006-1355.2018.05.030 Abstract ( )   PDF (2210KB) ( )   To solve the problem that the boundary of detection concentrated in the frequency range of larger amplitude by EWT method, the improved EWT based on spectrum trend is proposed by studying the method of the EWT in the frequency domain by extracting the maximum value to segment the spectrum. The simulation signal and the vibration signal of vehicle seat horizontal driver machine are tested by improved EWT, and the results indicate that the method can obtain the meshing frequency and its octave with its side band. The demodulation analysis of the modulated signal is realized by performing Hilbert transform on the component. Related Articles | Metrics

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Fault Diagnosis Method of Rolling Bearings based on Adaptive Multi-scale Dispersion Entropy 2018, 38(5): 173-180.  DOI: 10.3969/j.issn.1006-1355.2018.05.031 Abstract ( )   PDF (1834KB) ( )   Related Articles | Metrics

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Feature Extraction Method of Gear Compression Sampling Signals based on Extended Bispectrum 2018, 38(5): 180-185.  DOI: 10.3969/j.issn.1006-1355.2018.05.032 Abstract ( )   PDF (2068KB) ( )   Related Articles | Metrics

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Rolling Bearing Fault Diagnosis Method based on Refined Composite Multi-scale Entropy Eigenvector Correlation Coefficients 2018, 38(5): 186-191.  DOI: 10.3969/j.issn.1006-1355.2018.05.033 Abstract ( )   PDF (1838KB) ( )   Related Articles | Metrics

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Fault Feature Extraction Method based on Mathematical Morphology Filtering and Adaptive Empirical Wavelet Transform 2018, 38(5): 192-197.  DOI: 10.3969/j.issn.1006-1355.2018.05.034 Abstract ( )   PDF (1758KB) ( )   According to the non-linear and non-stationary characteristic of reciprocating compressor vibration signal, a fault feature extraction method based on adaptive empirical wavelet transform and mathematical morphology filtering is proposed. The method begin with using empirical wavelet transform, adaptively segments the Fourier spectrum by extracting the scale-space curve to separate the different modes, and then constructs adaptive band-pass filters in the frequency domain so as to construct orthogonal wavelet functions and extract AM-FM components that have compact support in Fourier spectrum. After segmenting the Fourier spectrum, the method filters the AM-FM components based on mathematical morphological. Different from other method, the structure elements in this paper are constructed according to the impact characteristics of reciprocating compressor. At last the method quantitatively analyzes AM-FM components by using the multiscale fuzzy entropy in order to identify and classify the fault of reciprocating compressor. Experiments and calculation results prove that this method can effectively diagnose the fault of reciprocating compressor. Related Articles | Metrics

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Application of Extended Kalman Filter Method to Typical Rotor Fault Diagnosis 2018, 38(5): 198-203.  DOI: 10.3969/j.issn.1006-1355.2018.05.035 Abstract ( )   PDF (2249KB) ( )   The rotor fault diagnosis is a key problem of rotor dynamics. Based on multiple model adaptive estimation, Literature 1 proposed a fault diagnosis method by getting the rotor crack parameters. For this problem, a method of typical rotor fault diagnosis is proposed based on extended kalman filter (EKF). For the Jeffcott rotor, several fault models (misalignment, bending and crack faults) are built. Fault parameter estimation equations are set up based on extended kalman filter and weighted global iteration (EKF-WGI). Via the experiment verification of misalignment fault, crack fault and bending fault on bently rotor, it is proved that this proposed method is effective in rotor fault diagnosis. Compare with the traditional diagnosis methods to extract spectrum features, it can estimate the fault parameters accurately without experiences and fault cases, which is more targeted in the rotor fault diagnosis. Related Articles | Metrics

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Damage Analysis of Clips of PR Type Fasteners of Subways 2018, 38(5): 204-207.  DOI: 10.3969/j.issn.1006-1355.2018.05.036 Abstract ( )   PDF (1841KB) ( )   Related Articles | Metrics

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Bearing Diagnosis based on Deep Neural Network of Auto-encoder yuan wenjun 2018, 38(5): 208-214.  DOI: 10.3969/j.issn.1006-1355.2018.05.037 Abstract ( )   PDF (1716KB) ( )   Related Articles | Metrics

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Analysis of the Vibration Attenuation System with a Nonlinear Energy Sink based on Magnified Precise Integration Method 2018, 38(5): 215-219.  DOI: 10.3969/j.issn.1006-1355.2018.05.038 Abstract ( )   PDF (1447KB) ( )   This paper has constructed the Duffing oscillator nonlinear energy sink by linear damping spring, we put a feasible method of constructing damping system of nonlinear energy sink, we use magnified precise integration method in nonlinear vibration control system, so we can get high precision solution, in the determine conditions, the vibration range of two degree of nonlinear energy sink vibration system and three degree of nonlinear energy sink vibration system, The external continuous stochastic excitation is applied to the nonlinear energy sink system, then we can determine the feasibility of constructing nonlinear energy sink in Duffing oscillator, this paper provide research direction and theoretical basis for the study of nonlinear energy sink. Related Articles | Metrics

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Structural Vibration Analysis and Vibration Attenuation Study for Internet-of-things Chassis Devices 2018, 38(5): 220-224.  DOI: 10.3969/j.issn.1006-1355.2018.05.039 Abstract ( )   PDF (1999KB) ( )   Related Articles | Metrics

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Simulation and Experimental Study on a Multi-DOF Vibration Isolation Platform for Suspended Radars 2018, 38(5): 225-229.  DOI: 10.3969/j.issn.1006-1355.2018.05.040 Abstract ( )   PDF (1884KB) ( )   In order to isolate multi-dimension vibration for radar suspended on the side wall, a isolation platform based on the parallel mechanism is proposed. The platform can isolate the vibration from six dimensions and the two-way isolation rod can work under both tension and compression state for the requirement that the whole platform must be suspended vertically. The function for isolation of the platform is simulated under sine excitation and half-sine-wave impact excitation using software Adams. The prototype is manufactured, and is tested on the vibration test table under the load of sine and half-sine-wave impact. The results shows that the vibration isolation platform has some consistency with those from simulations and have good vibration damping performance for protecting the radar suspended vertically. Related Articles | Metrics

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Design and Performance Analysis of Jet-exhaust Mufflers of Air Compressors Wen Hua-bing 2018, 38(5): 230-233.  DOI: 10.3969/j.issn.1006-1355.2018.05.041 Abstract ( )   PDF (1268KB) ( )   To reduce the high-pressure jet exhaust gas flow noise of air compressor, the empirical formula calculation methods of the acoustic performance for throttle injection, dissipative silencer with absorbent plates and small apertures spray were given. A composite muffler for jet exhaust gas flow was designed. The acoustic finite element model of the composite muffler was built in the Virtural.Lab to simulate the transmission loss performance of the muffler. The simulation result indicates that the empirical formula calculation results are close to the simulation results. A desirable broadband acoustic attenuation in wide range of 20Hz~3000Hz can be obtained. The average amount of noise elimination of the jet exhaust composite muffler is 57dB. Related Articles | Metrics

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Cooperative Simulation based on ADAMS and SIMULINK for a Stewart Active Vibration Control Platform 2018, 38(5): 234-238.  DOI: 10.3969/j.issn.1006-1355.2018.05.042 Abstract ( )   PDF (1860KB) ( )   Related Articles | Metrics

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Noise Source Identification and Low-noise Structure Design for Industrial Sewing Machines based on Partial Coherence Analysis 2018, 38(5): 239-243.  DOI: 10.3969/j.issn.1006-1355.2018.05.043 Abstract ( )   PDF (1708KB) ( )   Related Articles | Metrics

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Analysis and Design of Mouse Noise based on LMS Virtual Lab 2018, 38(5): 244-248.  DOI: 10.3969/j.issn.1006-1355.2018.05.044 Abstract ( )   PDF (1591KB) ( )   Related Articles | Metrics