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Shock Response Analysis of Axially-bolted Connection
HE Hua,LI Jia,BI Cheng
   2012, 32 (6): 78-80.   DOI: 10.3969/j.issn.1006-1335.2012.06.019
Abstract2323)      PDF       Save
A finite element model of the axially-loaded bolts was established to investigate their shock response characteristics. The test clamps for suspending and horizontally mounted bolts were manufactured. Data groups of acceleration response were obtained through the shock experiment. The acceleration and stress responses of the bolt connections were surveyed through the explicit dynamic analysis. Mutual comparison of simulation results and experimental results has verified the reliability of the application of the FEM method.
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Research of Testing Equipment Buffering Technology and Platform
GUO Yun-song,ZHANG Xin-wei,LI Jia,ZHOU Xiang-rong
   2012, 32 (6): 74-77.   DOI: 10.3969/j.issn.1006-1335.2012.06.018
Abstract1390)      PDF       Save
Testing equipment buffering platform can provide a reliable working environment for testing equipment, and offer an impact protection, stable power supply and sufficient operating space in the progress of impact test. Buffering platform is an elastic platform supported by FD40-10 air springs and polyurethane damper blocks. The platform was fitted out an isolation transformer and a high-power uninterrupted power supply according to the requirement of ship’s electrical power system. Based on theoretical analysis, laboratory test and practical equipment impact test, it is demonstrated that testing equipment buffering platform is necessary for reliably acquiring testing data during the impact test.
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Ultimate Shock Load of KA Bending Rubber Vibration Isolator
ZHOU Xiang-rong,LI Jia,FENG Hai-jun,GUAN Yue-ying
   2012, 32 (6): 70-73.   DOI: 10.3969/j.issn.1006-1335.2012.06.017
Abstract1640)      PDF       Save
The ultimate shock load of KA-100 bending rubber vibration isolator was investigated experimentally. In addition, numerical simulation was carried out to simulate the anti-shock performance of the isolator. Using the Yeoh hyperelastic model, viscodamping method and ABAQUS code, the ultimate shock load of the isolator was analyzed considering geometrical non-linearity effect. Good agreement between the numerical results and experimental results proves the efficiency of the numerical method.
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Performance Analysis of Six-rod Shock-isolation Mount
DING Wei,GUO Yun-song,LI Jia
   2012, 32 (6): 66-69.   DOI: 10.3969/j.issn.1006-1335.2012.06.016
Abstract1686)      PDF       Save
A mechanical model of a six-rod shock-isolation mount with different crash-constraints was established. The dynamic characteristics of the shock-isolator were studied. A shock test was then carried out for the six-rod shock-isolation mount. The shock response and several key points for design of the six-rod shock-isolation mount were summarized through the comparison between theoretical and experimental results.
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Effects of Viscoelastic Dampers on Vibration Fatigue Behavior of Steel Trusses
SUN Tian-fu;LIN Gao;LI Jian-bo;YU Ya-xin
   2012, 32 (3): 55-58.   DOI: 10.3969/j.issn.1006-1355.2012.03.013
Abstract1529)            Save
In order to study the effects of viscoelastic dampers on fatigue behavior of steel trusses, the equivalent stiffness of viscoelastic dampers was derived. Based on random load, and according to load’s power spectral density(PSD), structure’s frequency response and the structure’s modal, the fatigue behavior of the steel trusses were calculated and compared. These working conditions included that there was no viscoelastic damper added to the structure and that there were viscoelastic dampers with different damping coefficients respectively added to the structure. The result indicates that viscoelastic dampers can extend the structure’s fatigue lifespan efficiently. It is found that with the increase of the damping coefficient, the structure’s fatigue lifespan increases at first and decreases thereafter. Therefore structure’s fatigue resistant ability can be optimized through the best choice of the damping coefficients.
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《Computation Model and Modal Verification for an Engine Mount System Based on Dynamic Stiffness Test》
SONG Xiang-rong;JIN Yong-jun;LI Jian-kang;ZHENG Li-hui
   2010, 30 (4): 36-39.   DOI: 10.3969/j.issn.1006-1355.2010.04.010
Abstract1976)      PDF(pc) (1428KB)(1880)       Save
The practicality and reliability of computation model are the key problems in model building. The dynamic model of the linear system does not adapt to the nonlinearparameter system. In this paper, the stiffness and damping parameters of an engine mount system are obtained in experiments. The corresponding mass matrix and stiffness matrix are used for establishing the dynamic computation model of the engine mount system. The model is validated by relative analysis of operational modal and calculated modal. Results indicate that the computation model including dynamic stiffness parameters is more practical than the traditional model of static stiffness.
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《Comparative Study on Speech Intensification Algorithms in Strong Noise Background》
CAO Bin-fang;LI Jian-qi;LI Ting
   2010, 30 (1): 55-58.   DOI: 10.3969/j.issn.1006-1355.2010.01.055
Abstract2035)      PDF(pc) (1046KB)(1353)       Save

The principle of speech enhancement and the method of extracting speech signals from strong noise background are introduced. Three kinds of speech intensifying algorithms based on spectrum subtraction algorithm, wiener filtering and wavelet transform, respectively, are comparatively studied. However, the two purposes of the speech enhancement algorithms, to enhance articulation and to enhance the understandability, are not related each other, and even in contradiction sometimes. Therefore, a good speech enhancement algorithm is in fact a compromise between the two purposes according to the requirement of application. In this paper, results of numerical experiment of the three algorithms are compared and studied. The results demonstrate that the speech enhancement algorithm using wavelet ransform is more efficient than the others.

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