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- 저자 : Huaping Ding (검색결과 2 건)
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Ke Sun,Wei Zhang,Huaping Ding,Robin E. Kim,Billie F. Spencer Jr. 국제구조공학회 2017 Smart Structures and Systems, An International Jou Vol.19 No.1
The operation of subway trains induces secondary structure-borne vibrations in the nearby underground spaces. The vibration, along with the associated noise, can cause annoyance and adverse physical, physiological, and psychological effects on humans in dense urban environments. Traditional tethered instruments restrict the rapid measurement and assessment on such vibration effect. This paper presents a novel approach for Wireless Smart Sensor (WSS)-based autonomous evaluation system for the subway train-induced vibrations. The system was implemented on a MEMSIC\'s Imote2 platform, using a SHM-H high-sensitivity accelerometer board stacked on top. A new embedded application VibrationLevelCalculation, which determines the International Organization for Standardization defined weighted acceleration level, was added into the Illinois Structural Health Monitoring Project Service Toolsuite. The system was verified in a large underground space, where a nearby subway station is a good source of ground excitation caused by the running subway trains. Using an on-board processor, each sensor calculated the distribution of vibration levels within the testing zone, and sent the distribution of vibration level by radio to display it on the central server. Also, the raw time-histories and frequency spectrum were retrieved from the WSS leaf nodes. Subsequently, spectral vibration levels in the one-third octave band, characterizing the vibrating influence of different frequency components on human bodies, was also calculated from each sensor node. Experimental validation demonstrates that the proposed system is efficient for autonomously evaluating the subway train-induced ambient vibration of underground spaces, and the system holds the potential of greatly reducing the laboring of dynamic field testing.
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Zhongyang Li,Qudong Wang,Huaping Tang,Tianwen Liu,Chuan Lei,Haiyan Jiang,Wenjiang Ding 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.10
The variation of microstructure and mechanical properties along the cross section of squeeze cast Al-5Mg-3Zn-1Cu-1Sialloy is studied under both squeeze-cast and peak-aged condition (470 °C × 24 h + 125 °C × 24 h). For squeeze-cast alloy,along the depth direction, second dendrite arm space and the percentage of -Al increase significantly, while the volumefraction of T-Mg32(AlZnCu)49 and Mg2Siphase showed a dramatic decrease. The ultimate tensile strength of squeeze-castalloy slightly decreased from 357.04 MPa for the surface layer to 344.21 MPa for the central layer, yield strength droppedfrom 296.86 MPa to 241.03 MPa, but the elongation almost tripled from 1.42% to 3.78%. After peak aging, the ultimatetensile strength of surface layer and central layer reached 538.45 MPa and 504.03 MPa, yield strength reached 447.46 MPaand 442.65 MPa, and the elongation reached 5.23% and 3.97% respectively. Meanwhile the difference of ultimate tensilestrength and elongation was increased, but that of yield strength reduced after aging treatment. Precipitation strengtheningis the main strengthening mechanism while the improvement in ductility is due to the dissolution of T-Mg32(AlZnCu)49 andthe morphological change of eutectic Mg2Si.
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