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Subway Embedded Track Geometric Irregularity Safety Limits

Chinese Journal of Mechanical Engineering 2021年第5期34卷 322-331页

作者： Yuxiang Zhang Jian Han Huilai Song Yu Liu School of Economics and Management Southwest Jiaotong UniversityChengdu 610031China School of Mechanical Engineering Southwest Jiaotong UniversityChengdu 610031China School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China

A coupling dynamic model of a subway train and an embedded track is established to study the safety limits of track *** simulated vehicle system was a 74-degrees of freedom multi-rigid body model,and the rail was a Timoshenko *** slab was a three-dimensional solid finite element *** sensitive wavelength irregularity was first studied,and then the safety limit of the sensitive wavelength was *** wheel-rail lateral force exhibited a substantial effect on the track alignment and gauge irregularity safety *** wheel-rail vertical force and the rate of wheel load reduction significantly affected the height and cross-level irregularity safety *** results demonstrate that the safety limits of the alignment,gauge,height,and cross-level embedded track geometric irregularity are 5.3 mm,[−10.5,8]mm,5.6 mm,and 6 mm,respectively.

关键词： Embedded track Irregularity sensitive wavelength Safety limit

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Wheel/rail dynamic interaction due to excitation of rail corrugation in high-speed railway

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Science China(Technological Sciences) 2015年第2期58卷 226-235页

作者： WANG Kai Yun LIU Peng Fei ZHAI Wan Ming HUANG Chao CHEN Zai Gang GAO JianMin State Key Laboratory of Traction Power Southwest Jiaotong University

Characteristics of wheel-rail dynamic interaction due to the rail corrugation in a high-speed railway are analyzed based on the theory of vehicle-track coupled dynamics in this *** of the corrugation wavelength and depth on the wheel-rail dynamic performance are *** results show that,under the excitation of a measured rail corrugation,the wheel-rail dynamic interaction of high-speed railway is enhanced obviously,and the high-frequency dynamic force between wheel and rail is generated,which has an obvious impact on the vibrations of the wheelset and rail,and little effect on the vibration of the frame and *** the corrugation wavelength is shorter than the sensitive wavelength,the wheel-rail vertical force will increase with the growth of the corrugation wavelength,otherwise,it will ***,the wheel-rail vertical force keeps increasing with the growth of corrugation ***,if the corrugation wavelength is shorter than the sensitive wavelength,the wheel-rail vertical force will increase with the decrease of the running speed,otherwise,it will *** is also found that the critical wavelength of corrugation increases with the growth of the corrugation depth and the running speed,and the critical depth of corrugation is nonlinearly related to the sensitive wavelength.

关键词： dynamic interaction rail corrugation high-speed railway critical wavelength critical depth sensitive wavelength

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Spectroscopy-Based Soil Organic Matter Estimation in Brown Forest Soil Areas of the Shandong Peninsula, China

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Pedosphere 2019年第6期29卷 810-818页

作者： GAO Lulu ZHU Xicun HAN Zhaoying WANG Ling ZHAO Gengxing JIANG Yuanmao College of Resource and Environment Shandong Agricultural UniversityTai’an 271018(China National Engineering Laboratory for Efficient Utilization of Soil Resources Tai’an 271018(China College of Horticulture Science and Engineering Shandong Agricultural UniversityTai’an 271018(China

Soil organic matter (SOM) is important for plant growth and production. Conventional analyses of SOM are expensive and time consuming. Hyperspectral remote sensing is an alternative approach for SOM estimation. In this study, the diffuse reflectance spectra of soil samples from Qixia City, the Shandong Peninsula, China, were measured with an ASD FieldSpec 3 portable object spectrometer (Analytical Spectral Devices Inc., Boulder, USA). Raw spectral reflectance data were transformed using four methods: nine points weighted moving average (NWMA), NWMA with first derivative (NWMA + FD), NWMA with standard normal variate (NWMA + SNV), and NWMA with min-max standardization (NWMA + MS). These data were analyzed and correlated with SOM content. The evaluation model was established using support vector machine regression (SVM) with sensitive wavelengths. The results showed that NWMA + FD was the best of the four pretreatment methods. The sensitive wavelengths based on NWMA + FD were 917, 991, 1 007, 1 996, and 2 267 nm. The SVM model established with the above-mentioned five sensitive wavelengths was significant ( R 2 = 0.875, root mean square error (RMSE) = 0.107 g kg −1 for calibration set;R 2 = 0.853, RMSE = 0.097 g kg −1 for validation set). The results indicate that hyperspectral remote sensing can quickly and accurately predict SOM content in the brown forest soil areas of the Shandong Peninsula. This is a novel approach for rapid monitoring and accurate diagnosis of brown forest soil nutrients.

关键词： Brown forest soil Hyperspectral remote sensing Nine points weighted moving average Standard normal variate sensitive wavelength Spectral reflectance Support vector machine regression

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