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AnOverviewofLaboratoryTestingandDesignoftheSound InsulationofMetalStud/GypsumBoardWalls 2018, 38(1): 1-8.  DOI: 10.3969/j.issn.1006-1355.2018.01.001 Abstract ( )   PDF (2269KB) ( )   Related Articles | Metrics

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ModalTestoftheBox-girderModelBasedonPre-testAnalysis 2018, 38(1): 9-15.  DOI: 10.3969/j.issn.1006-1355.2018.01.004 Abstract ( )   PDF (1367KB) ( )   In engineering, the sound absorption material is usually laid on the boundary of the sound field to reduce the noise. Generally speaking, the impedance of the acoustic material varies with the frequency. This is especially true at low frequencies. Thus, the acoustic model analysis problem becomes a nonlinear eigenvalue problem. Modern finite element analysis software cannot carry out the acoustic modal analysis of this frequency dependent impedance boundary. The impedance of the absorption material is usually set to constant in engineer to avoid the solving of nonlinear eigenvalue problem. However, this will bring large error in modal frequency results. This paper aims to extend the application of a newly-developed resolvent sampling based Rayleigh-Ritz projection method (RSRR) to the solution of this kind of problem. The algorithm is implemented in the commercial finite element software ANSYS. Representative numerical examples aregiven to show the high precision and good numerical stability of this method. It is proven to be a general method for the modal analysis of large-scale sound field. Related Articles | Metrics

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Calculation and Analysis of Vibration Isolation Performance of Airplane Engine Pylon Systems with Variable Damping and Stiffness 2018, 38(1): 16-20.  DOI: 10.3969/j.issn.1006-1355.2018.01.003 Abstract ( )   PDF (1344KB) ( )   Related Articles | Metrics

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Modal Test of the Box-girder Model Based on Pre-test Analysis 2018, 38(1): 21-25.  DOI: 10.3969/j.issn.1006-1355.2018.01.004 Abstract ( )   PDF (1624KB) ( )   Taking the box-girder model as the experimental object, a method based on pre-test analysis was used to identify the box-girder model. Firstly, based on the results of modal analysis of finite element model, the reasonable distribution scheme and the optimal excitation point are determined by pre-test analysis. And the modal identification of free-standing box-girder model using vibration exciter based on the pre-test results. Finally, the correlation between the experimental modal and the finite element modal is analyzed to verify the credibility of the experimental modal data. The experimental results show that with the finite element analysis results within 10% of the four order modal frequency identification value, the first three order within%5. And the results of correlation analysis showed that the similarity between the measured modal data and the finite element results is high, especially the correlation of the first two modes is up to more than 90%. Related Articles | Metrics

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High-frequency Response Prediction of Uncertainty Structures based on Interval Perturbation Approach 2018, 38(1): 26-31.  DOI: 10.3969/j.issn.1006-1355.2018.01.005 Abstract ( )   PDF (1156KB) ( )   Statistical energy analysis is an effective method to deal with the high-frequency sound and vibration problem in many fields such as aeronautics, vehicle, shipping and nuclear energy. The uncertainty of the damping loss factor and coupling loss factor of statistical energy analysis was considered in this paper, and the interval variables were utilized to represent the damping loss factors and coupling loss factors with the measurement errors. The high-frequency dynamic response prediction method of uncertain structures was proposed by the interval perturbation method, and then the computing method of the total energy intervals of the subsystems was also provided. The effect level of measurement errors of parameters on the predicted steady-state response was revealed. The rationality and effectiveness of the theory was validated by the experiment on the two coupled plated. Related Articles | Metrics

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A Size Optimization Method for Sound Insulation Cavities at the Bottom of Capacitors 2018, 38(1): 32-35.  DOI: 10.3969/j.issn.1006-1355.2018.01.006 Abstract ( )   PDF (1429KB) ( )   At the bottom of the capacitor add sound insulation is one of the main currently methods to reduce the noise of capacitor. In order to reduce the noise of the capacitor more effectively, this paper presents a dimension optimization method of the bottom of the capacitor sound insulation. The principle of the capacitor sound insulation is analyzed, and the design theory of the the capacitor sound insulation is given. The main contribution frequency of the noise is determined by the capacitor test experiment, and the finite element model of the acoustic cavity is established. In the LMS Virtual Lab Acoustics, the finite element method is used to calculate the vibro acoustic coupling of the acoustic cavity. The characteristic curve between the sound insulation and the noise frequency is obtained. In the LMS Virtual Lab Optimization module, the DOE technique is used to optimize the structural parameters of the sound insulation cavity. Finally, a kind of capacitor is taken as an example, and the noise experiment is carried out on different capacitor sound insulation. The experimental results show that the proposed optimization method can effectively improve the quality and speed of the design of the bottom of the capacitor sound insulation. Related Articles | Metrics

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Numerical Analysis for Transversal Modals of Silencers Using Collocation Method with Hermite Radial Base-function and Point-interpolation 2018, 38(1): 36-41.  DOI: 10.3969/j.issn.1006-1355.2018.01.007 Abstract ( )   PDF (1500KB) ( )   Related Articles | Metrics

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Study on Sound Transmission Characteristics of Condenser Coolant Channels 2018, 38(1): 42-45.  DOI: 10.3969/j.issn.1006-1355.2018.01.008 Abstract ( )   PDF (1277KB) ( )   Aiming for clarification of sound transmission characteristic of condenser coolant channel and acoustic design level improvement of circulation coolant system, heat exchange equation is coupled into plane wave transmission equations and then the acoustic transfer matrix is derived. A whole condenser acoustic transfer matrix is deduced by employing the configuration parameters and the acoustic transfer loss is calculated. The calculated results are compared to data collected in experiment and agree well with them. Two way fluid and structure interaction analysis is conducted on single heat transfer pipe with surrounding flow. The results show that effect of surrounding steam flow on internal flow characteristics could be neglected. Experimental results also show that flow fluctuation is the main exciting source of pipe wall vibration as coolant flow sound pressure fluctuation and coolant pipe wall vibration are closely interacted. Variation of condenser construction parameters can be employed to regulating coolant sound transfer loss in circulation coolant system. Related Articles | Metrics

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Vibration Characteristics Analysis of a Lube Cooling Fan 2018, 38(1): 46-51.  DOI: 10.3969/j.issn.1006-1355.2018.01.009 Abstract ( )   PDF (1877KB) ( )   In order to avoid the resonance caused by the working speed of the rotor and relevant excitation frequency, the vibration characteristics of the rotor are analyzed by the combination of the experimental and the numerical modal analysis. The rotor before improved is compared with the current one. The results show that the working speed is close to the resonant speed which corresponds to the oscillating force generated by the stator. Each stages of natural frequency increases while the margin of resonance decreases compared to the former rotor. As to avoid the security risks, such as fatigue fracture, the integrity of the fan should be ensured during its working. Related Articles | Metrics

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The Influence of Bolt Joint Characteristics on Bending Stiffness of Rotor Joint Surface 2018, 38(1): 52-57.  DOI: 10.3969/j.issn.1006-1355.2018.01.010 Abstract ( )   PDF (1585KB) ( )   Related Articles | Metrics

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Modeling and Experiment Analysis of Dynamic Vibration Absorbers with Porous Fluid Dampingage/gi 2018, 38(1): 58-62.  DOI: 10.3969/j.issn.1006-1355.2018.01.011动传递率 Abstract ( )   PDF (1383KB) ( )   For the purpose of protecting vibration-sensitive communication components from excitation, porous fluid damping dynamic vibration absorber was presented for vibration reduction. The dynamical model of vibration absorber was established, and the stiffness parameters and optimal damping parameters were determined. This paper analyzed the influence of damping hole parameters on frictional damping and local damping force, and gave the design method for the damping of the absorber. Experiments were also conducted to verify vibration reduction performance. The acceleration transmissibility of the vibration absorber was tested in different media (water and silicone oil) respectively. The test results demonstrated that the working frequency of dynamic vibration absorber is about 1.6-2Hz. With the increase of fluid viscosity, vibration absorption effect is reduced. The acceleration transmissibility can be attenuated by about 53% in the water medium. It shows that the porous fluid damping dynamic vibration absorber has a good inhibitory effect on low frequency vibration. Related Articles | Metrics

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Equivalent Stiffness of the Rubber Stern Bearing of a Propulsion Shafting System 2018, 38(1): 63-67.  DOI: 10.3969/j.issn.1006-1355.2018.01.012 Abstract ( )   PDF (1588KB) ( )   The equivalent stiffness of the rubber stern bearing of a propulsion shafting system was studied and a method was proposed for computing the equivalent stiffness and support position. A contact FEM model of the shaft-bearing system was built to calculate the surface pressure and displacement of the bearing. Two models associated with the single- support and multi-support were used respectively to obtain the equivalent stiffness. The results show that the single-support model is comparatively accurate for computing the displacement of the shaft but not accurate enough for the rotation angle. Compared with the single-support model, the multi-support model is able to describe the deformation of the shaft in higher accuracy and the equivalent dynamic stiffness can result in accurate frequency response characteristics. Particularly at low frequencies (less than 60 Hz), the responses are almost the same as that of the shaft-bearing model. Related Articles | Metrics

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Analysis of Flow Regeneration Noise of Resonant Mufflers 2018, 38(1): 68-73.  DOI: 10.3969/j.issn.1006-1355.2018.01.013 Abstract ( )   PDF (2349KB) ( )   To analyze the relationship between the flow regeneration noise (FRN) and the flow velocity as well as the temperature，the fluid and acoustic model of a resonant muffler model was established by means of LES-AA method.The test bench was built and the fluid and acoustic model was verified.On this basis,the FRN and turbulent kinetic energy (TKN) of the muffler were calculated. The computation results reveal that both FRN and TKN have higher numerical values in structural mutation of muffler and the nephogram distribution of the two parameters is in accordance with each other. The FRN frequency is mainly under 3000Hz. The sound pressure level increases with the rising of inlet flow velocity and reversely with the rising of the air flow temperature. But the spectral characteristic is less influenced by flow velocity and temperature. The FRN characteristics of multi-field coupling can be used as a reference for the resonant muffler design. Related Articles | Metrics

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Engineering Design of Shock Isolations for Mobile-platform Opto-electronic Equipment 2018, 38(1): 74-78.  DOI: 10.3969/j.issn.1006-1355.2018.01.014 Abstract ( )   PDF (1384KB) ( )   Related Articles | Metrics

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Study on the Vibration Power Flow of Finite Plates by Using Wave Method 2018, 38(1): 79-84.  DOI: 10.3969/j.issn.1006-1355.2018.01.015 Abstract ( )   PDF (1704KB) ( )   The coupled traveling-wave model was established for finite-sized cross-shaped plates. Through the combination and dispersion of amplitude coefficient matrix of the bending wave and the inward wave, the general form of the coupled motion equation at the board connection is obtained Coupled motion equations for line connections were established. Semi-analytical results and finite element numerical results were compared to verify the convergence and accuracy of the MATLAB program. The effects of the connection angle of plates and excitation angle on bending wave power flow and in-plane wave power flow were analyzed. In lower frequency, the bending wave power flow was significantly larger than the in-plane wave power flow, and the in-plane vibration power flow could be negligible. As the frequency increased, the in-plane wave power flow increased, which may be consistent with the bending wave magnitude. In the whole frequency domain, the bending vibration power flow of the excited plate increased with the increase of the excitation angle, while the in-plane wave power flow of receiving plate was leaded by the opposite effects of the waveform transformation and direct excitation. When the plate connection angle approached to 900, the power flow of the receiving plate was larger, and the reduction of vibration was obvious. Related Articles | Metrics

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Dropping Damage Evaluation of Vulnerable Components for Suspension Systems CHEN An-Jun 2018, 38(1): 85-89.  DOI: 10.3969/j.issn.1006-1355.2018.01.016 Abstract ( )   PDF (1746KB) ( )   The work aims to establish the dimensionless dropping shock dynamic equations with the suspension system of critical components considered as the object. The fourth order Runge-Kutta numerical analysis method is used to solve the dynamic equations. To derive the dropping damage boundary surfaces of critical component, the system parameter, dimensionless dropping shock velocity, frequency ratio, damping ratio or suspension angle are selected as basic evaluation quantities. The effects of the suspension angle, the frequency ratio and the damping ratio on the dropping damage boundary surfaces of critical component are discussed. The case study shows that a higher frequency ratio is beneficial to the product protection. Under the minor damping condition, the system with damping ratio in the certain range has a better protection performance. the safety area with a smaller suspension angle is larger. In order to protect the product, the shock?resistance of system should be improved by considering?the?effects?of every?parameter on dropping damage boundary surfaces?synthetically in the design process of suspension system. Related Articles | Metrics

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Analysis of Transverse Vibrations of Moving Belt caused by Fulcrum Motion 2018, 38(1): 90-93.  DOI: 10.3969/j.issn.1006-1355.2018.01.017 Abstract ( )   PDF (1149KB) ( )   Related Articles | Metrics

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Rotor Rubbing FE Model Updating Based on DPSO 2018, 38(1): 94-98.  DOI: 10.3969/j.issn.1006-1355.2018.01.018 Abstract ( )   PDF (1531KB) ( )   Rotor rubbing FE model updating method based on DPSO (Particle swarm optimization algorithm based on dichotomy) model updating theory and modal test was proposed to improve the precision of a flexible shaft of the rigid-flexible coupled rotor rub-impact model dynamic simulation. According to the model updating theory, based on the FE model analysis results and experimental results, and the DPSO method is adopted as the optimization algorithm for model updating. It improves the speed and accuracy of the finite element model updating and avoids getting into the local optimal solution in the iterative optimization of PSO. Research indicates that the accuracy of the model obtained by this method has been greatly improved, and the structure characteristic of the rotor has been more accurately reflected. The updated model is applied to the research of rubbing fault, and the influence of speed variation on the dynamic characteristics of rotor rubbing is considered. The experimental results show that the simulation results are in good agreement with the experimental results, which is a safe and stable operation of the rotor system in practical engineering. The results show that the simulation results are in good agreement with the experimental results. Provide some practical reference value. Related Articles | Metrics

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Noise Prediction and Reduction of the Cylinder Head Cover of a Diesel Engine 2018, 38(1): 99-102.  DOI: 10.3969/j.issn.1006-1355.2018.01.019 Abstract ( )   PDF (1421KB) ( )   Related Articles | Metrics

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Signal De-noising Method for Whole Vehicle Drivability Evaluation Based onWavelet Transform 2018, 38(1): 103-108.  DOI: 10.3969/j.issn.1006-1355.2018.01.020 Abstract ( )   PDF (1344KB) ( )   The acceleration collected by the drivability evaluation are mixed with noise, seriously affecting the accuracy of the data. Aiming at the problem that the accuracy of drivability evaluation indexes are affected by the noise in the data collected by the vehicle under different working conditions, a wavelet de-noising method is proposed for the pretreatment of the drivability evaluation data: The optimal wavelet basis function and threshold selection rules are determined by evaluating the signal-to-noise ratio and the root mean square error. The signal is decomposed by multiple scales. The wavelet decomposition layer is determined by the composite index constructed by the smoothness and root mean square error structure. So as to realize the filtering of the noise. The results of the analysis of the acceleration of the same gear shift condition show that the wavelet de-noising method not only retains the vibration and shock in the shift condition but also can effectively extract the useful frequency of the signal components and the evaluation index of the shift condition. Related Articles | Metrics

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Design of Semi-active Air Suspension Systems Based on Fuzzy Sliding Mode Back-stepping 2018, 38(1): 109-113.  DOI: 10.3969/j.issn.1006-1355.2018.01.021 Abstract ( )   PDF (1356KB) ( )   In order to study the influence of semi - active air suspension system on vehicle running performance, a fuzzy sliding mode backstepping control based on semi-active air suspension is proposed. Firstly, a quarter-car model for semi-active air suspension system is established. Then, the fuzzy logic systems are employed to approximate the unknown function and the problem that damping coefficient is not easy to measure is solved. The controller designed in this paper can adapt to the change of the system parameters caused by the change of the vehicle running state or the environment within a certain range. The results show that, compared with passive suspension, the proposed fuzzy sliding mode backstepping controller in this paper is more effective in improving the vibration reduction effect of the semi- active air suspension system. Related Articles | Metrics

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Research on Vibration Insulation Technique of Steering Wheel Rubber Mounts 2018, 38(1): 114-117.  DOI: 10.3969/j.issn.1006-1355.2018.01.022 Abstract ( )   PDF (1556KB) ( )   Related Articles | Metrics

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Dynamics of Double-speed Transmission 2018, 38(1): 118-121.  DOI: 10.3969/j.issn.1006-1355.2018.01.023 Abstract ( )   PDF (1507KB) ( )   Related Articles | Metrics

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Experiment Identification and Optimization of Vehicle’s Powertrain Bending Modals 2018, 38(1): 122-126.  DOI: 10.3969/j.issn.1006-1355.2018.01.024 Abstract ( )   PDF (1523KB) ( )   Related Articles | Metrics

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Research of Influencing Factors of Exhaust System Modals 2018, 38(1): 127-129.  DOI: 10.3969/j.issn.1006-1355.2018.01.025 Abstract ( )   PDF (1257KB) ( )   This paper researches on application and influencing factor of exhaust system by CAE. Find the key parts that influencing on vibration type and frequency. This can help control exhaust vibration in prophase and resolve problem in anaphase and help test relativity analyzing. Related Articles | Metrics

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Optimized Design of Parameters of Tractor Front Axle Suspensions 2018, 38(1): 130-136.  DOI: 10.3969/j.issn.1006-1355.2018.01.026 Abstract ( )   PDF (1891KB) ( )   Related Articles | Metrics

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Study on the Coupled Vibration of Underframe Active Rotational Equipment and Carbody 2018, 38(1): 137-142.  DOI: 10.3969/j.issn.1006-1355.2018.01.027 Abstract ( )   PDF (2114KB) ( )   Based on the test of high-speed trains, the results show that the unbalance of the quality of the active rotating equipment under the vehicle will cause the coupling vibration of the equipment and the train floor, which impact on vehicle dynamics performance. In order to study the coupling vibration characteristics of active vehicle and vehicle body, considering the elastic vibration of carbody, based on the rigid flexible coupling dynamic model of the vehicle body and the vehicle suspension equipment, analyzing the influence of the unbalance of the active rotating equipment on the vibration of the equipment and the car body is analyzed. The results show that the low order mode of active devices in the specific frequency range, with the increase of unbalance, the vibration of car body increases gradually. To reduce the influence of the vibration of the active equipment on the dynamic performance of the vehicle, study on the suspension parameters matching of active equipment, obtain the optimal suspension stiffness and damping. At the same time, the two stage vibration isolation scheme is proposed. It is found that the two stage vibration isolation scheme can effectively reduce the vertical vibration of carbody, with a maximum reduction of about 15% at a certain speed. Related Articles | Metrics

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Influence of Wheel Tread Roughness on Sound Radiation of Traveling High-speed Trains 2018, 38(1): 143-146.  DOI: 10.3969/j.issn.1006-1355.2018.01.028 Abstract ( )   PDF (2199KB) ( )   Related Articles | Metrics

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Influence of Polygonal Wheels on Interior Noise of High-speed Trains 2018, 38(1): 147-150.  DOI: 10.3969/j.issn.1006-1355.2018.01.029 Abstract ( )   PDF (1473KB) ( )   Abstract: Abnormal noise generates in coach when high-speed trains operate. The tests of noise in the coaches and roughness of the corresponding wheels were carried out before and after re-profiling of wheels. Through analysis the different characters of noise and roughness before and after re-profiling of wheels, it was found that the coaches which noise were abnormal, the corresponding wheels were serious polygonal. The polygonal wheels were improved and the level of interior noise was reduced after re-profiling of wheels. That polygonal wheel was the main reason to cause abnormal noise inside the coaches. The result of study indicates that the abnormal noise is caused by the serious polygonal wheels. The level of polygonal wheels can be monitored to some extent by the measurement of noise. The most effective method to solve the abnormal noise is re-profiling of wheels. The conclusion plays an important role to monitor polygonal wheel and prevent worse influence to high-speed trains due to serious polygonal wheels. Related Articles | Metrics

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Design of Shock Absorbers for a Shipboard Electronic Cabinet 2018, 38(1): 151-155.  DOI: 10.3969/j.issn.1006-1355.2018.01.030 Abstract ( )   PDF (1529KB) ( )   In order to improve the reliability and stability of working state of electronic cabinets, in addition to strengthening the strength of design of the electronic cabinet itself, the overall vibration isolation system can be uesd to improve its anti-vibration, impact resistance. Based on the non - resonant principle, a new type of damper structure for shipboard was designed and its structural parameters were calculated. The finite element simulation model was established by ANSYS Workbench. Additionally，the finite element analysis was carried out according to the vibration and impact characteristics in shipboard environment. Finally, the simulation results were verified by environmental vibration and impact test: the designed shock absorber met the vibration and shock requirements of the shipboard environment. Moreover，it can provide reference for the future optimization of structural parameters and the design of new shock absorber structure. Related Articles | Metrics

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Prediction of Airborne Cabin Noise Based on Closed Loop Computation 2018, 38(1): 156-159.  DOI: 10.3969/j.issn.1006-1355.2018.01.031 Abstract ( )   PDF (1290KB) ( )   Fast cabin noise prediction is of great importance to early acoustic design for ships. Based on traditional “S-P-R” approach, an closed loop computation instead of open loop method is put out by introducing acoustic elements and taking coupling energy between cabins into consideration, which improved the accuracy. This method is applied to predict the cabin noise of a large oil tanker and the results are compared with those from SEA computation. It is seen that the shortage from open loop computation can be overcome by using closed loop one Related Articles | Metrics

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Experimental Analysis of Vibration Isolation Effects ofWave Impedance Blocks under Highway Traffic Loads 2018, 38(1): 160-163.  DOI: 10.3969/j.issn.1006-1355.2018.01.032 Abstract ( )   PDF (1523KB) ( )   Related Articles | Metrics

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Study on Vibration Characteristics and Comfort of Integrated Transportation Hub 2018, 38(1): 164-170.  DOI: 10.3969/j.issn.1006-1355.2018.01.033 Abstract ( )   PDF (1647KB) ( )   Related Articles | Metrics

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Experimental Study on Sound Insulation Performance of SinglelayerWindows with Different Structural Types and Parametersn 2018, 38(1): 171-176.  DOI: 10.3969/j.issn.1006-1355.2018.01.034 Abstract ( )   PDF (2147KB) ( )   The influence of different parameters on sound insulation performances of single-layer windows were studied experimentally, including casement forms and specifications, window frame profiles, open mode and sealing form. The results show that casement forms have small effect on the weighted sound isolation of casement windows, however, the characteristic of low-frequency resonance was different significantly. Sound insulation performances is similar in low frequency for different types of casement forms, while vacuum glass and laminating-hollow glass have better performance in 200~2kHz band. The sound insulation performances of plastic steel windows is slightly better than broken bridge aluminium windows, and are significantly better than ordinary aluminum alloy windows. Enlarging thickness of window frame profiles can improve its sound insulation performance. Owing to the slighter effect of coincidence effects in middle-high frequency, casement windows’ sound insulation performances is better than sliding windows. Furthermore, the use of coated seals instead of seal strips is an efficient way to enhance sound insulation for sliding windows. This paper can provide the necessary basis and support for the sound insulation of the building design and window renovation. Related Articles | Metrics

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Research on the Accuracy of Dynamic Load Identification for Damaged Plates 2018, 38(1): 177-181.  DOI: 10.3969/j.issn.1006-1355.2018.01.035 Abstract ( )   PDF (1325KB) ( )   In order to study the problem of dynamic load identification, the effect of the accuracy of the identification information and the number of sensor layouts is improved. Firstly, the influence of the damage on the load recognition results is studied on the basis of the theory of time domain forward method, and then the influence of the position of the measuring point and the sampling time interval on the recognition accuracy is analyzed. The results were presented that the method can effectively identify the load on the non-damaged location, but the accuracy of identification for the damaged location is low. At the same time, by optimizing the arrangement of the sensor and selecting the appropriate sampling time interval, the recognition accuracy is improved to a large extent, which can provide reference for the accuracy of load identification Related Articles | Metrics

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Bearing Fault Feature Enhancement Method Based on Spectral Kurtosis and Teager Energy Operator 2018, 38(1): 182-187.  DOI: 10.3969/j.issn.1006-1355.2018.01.036 Abstract ( )   PDF (2256KB) ( )   The difficulty of resonance demodulation method is how to develop the parameters of band-pass filter, Spectral kurtosis can resolves this conundrum with selecting the suitable parameters of band-pass filter according to the characteristics of signal. In the case of strong background noise, SK is inadequate to extract local fault induced cyclic impacts from bearing vibrations due to In-band noise. Aimed at this issue, a novel fault diagnosis method for rolling bearings was proposed based on Spectral Kurtosis and Teager Energy Operator. Teager Energy Operator is employed to calculate the energy of signal after SK, which can suppress In-band noises and further enhance cyclic impact feature hidden in vibrations of faulty bearings after filtering. The frequency spectrum of the signal energy is then given to determine the health condition of bearings. The effectiveness of the method is examined by using both synthetic and experimental data. Related Articles | Metrics

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Prediction of Remaining Life of Rolling Bearings Based on Multi-frequency Scale Fuzzy Entropy and ELM 2018, 38(1): 188-192.  DOI: 10.3969/j.issn.1006-1355.2018.01.037 Abstract ( )   PDF (1360KB) ( )   Related Articles | Metrics

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Fault Diagnosis of Rolling Bearings Based on Interpolation Multi-scale Entropy and Fuzzy C-Means 2018, 38(1): 193-198.  DOI: 10.3969/j.issn.1006-1355.2018.01.038 Abstract ( )   PDF (1575KB) ( )   Multiscale entropy (MSE) is an effective method to measure the complexity of time series. In order to overcome the problem that the coarse-graining of MSE always miss the feature information, a cubic spline interpolation based time series algorithm called interpolation MSE (InMSE) is put forward to enhance the MSE. Firstly, the cubic spline interpolation time series is used to replace the original coarse-grained process and then the sample entropy is calculated at different scales. The simulation signal analysis results show the effectiveness and superiority of the proposed method by comparing the proposed method with the original MSE. Based on that, a new fault diagnosis method of rolling bearing is proposed based on MSE and fuzzy C- mean. Finally, the proposed method is applied to the rolling bearing experiment data analysis and the results show that the proposed method is more accurate than the MSE based fault diagnosis method. Related Articles | Metrics

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Application of Enhanced EmpiricalWavelet Transform to Rolling Bearings Fault Diagnosis 2018, 38(1): 199-203.  DOI: 10.3969/j.issn.1006-1355.2018.01.039 Abstract ( )   PDF (1958KB) ( )   Related Articles | Metrics

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Fault Diagnosis ofWeak Misalignment of Rotors Based on Spectral Kurtosis and VMD 2018, 38(1): 204-208.  DOI: 10.3969/j.issn.1006-1355.2018.01.040 Abstract ( )   PDF (1856KB) ( )   In order to solve the problem that the fault features of the rotors in weak misalignment under the noise interference are difficult to extract, a rotor fault diagnosis method was proposed based on Spectral Kurtosis and variational mode decomposition. Firstly, Spectral Kurtosis was used to filter out the signal background noise to enhance the fault characteristic correlation signal component. Then VMD (variational mode decomposition) was used to decompose the signal into IMFs (Intrinsic Mode Function); Finally the frequency spectrum of the IMFs were calculated to extract the fault feature of the rotor. The proposed method was applied in misalignment of rotors. The results showed that the proposed diagnosis method can more effectively and accurately extract the weak misalignment of rotor, superior to the diagnosis method based on Spectral Kurtosis and empirical mode decomposition (EMD). Related Articles | Metrics

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Failure Prognostic Prediction of Direct DriveWind Turbines Based on Algorithms of Random Forest and Adaptive Network-based Fuzzy Inferer System 2018, 38(1): 209-214.  DOI: 10.3969/j.issn.1006-1355.2018.01.041 Abstract ( )   PDF (1666KB) ( )   Aiming at the characteristics that the complicated operating conditions and single state parameter of wind turbine is complex and difficult to forceast potential failure，a fault prognostic method based on random forest algorithm (RF) and adaptive fuzzy neural network algorithm (ANFIS) was proposed. The high-dimensional and nonlinear of state features were fully considered，Using random forest algorithm, active power and operation parameters of the data driven model was established，relevancy of active power operation parameters and influence was calculated. ANFIS model was constructed to train error maximum value as the fault early warning threshold, the real-time monitoring running state of generator. This method was applied to 1.5 MW direct drive generator fault early warning analysis, results show that the method can advance warning generator health status，avoid serious accident. The evaluation results can carry out important guiding significance of preventive maintenance on wind farm. Related Articles | Metrics

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Dynamic Load Identification Approach Based on Bayesian Estimation 2018, 38(1): 215-221.  DOI: 10.3969/j.issn.1006-1355.2018.01.042 Abstract ( )   PDF (1635KB) ( )   Related Articles | Metrics

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Monitoring of Particle Mass Flow Rate in Pneumatic Conveying Based on Acoustic Emission 2018, 38(1): 222-224.  DOI: 10.3969/j.issn.1006-1355.2018.01.043 Abstract ( )   PDF (1559KB) ( )   Related Articles | Metrics

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Analysis and Solution of Vibration Failures Diagnosis for theMultistage Centrifugal Pumps 2018, 38(1): 225-228.  DOI: 10.3969/j.issn.1006-1355.2018.01.044 Abstract ( )   PDF (1430KB) ( )   The safety and reliability is the key to guarantee normal running for centrifugal pumps, while the vibration is a greatly negative factor. In order to solve the vibration problem, the HG8908C, a vibration data collection system of BEIJING JINGHANG company, was used to monitor the vibration signal on the centrifugal pump. By the vibration failures diagnosis methods, the vibration signal characteristic of amplitude domain, frequency domain and time domain were analyzed in detail and the fault patters generated were figured out. Based on the analytic outcome, controlling the install center for rotor, amplifying the radial-clearance and others solutions, were carried out. The tests results showed that the ways have a positive effect on it, and the pump could work longer hours in a good state. Besides, the vibration failures diagnosis methods were noticeable for solving the vibration problems on centrifugal pumps, and which is valuable for other similar situations. Related Articles | Metrics