An analytical solution to the vibration characteristics for continuous girder bridge-track coupling system and its application

Yulin Feng,Lizhong Jiang,Wangbao Zhou,Yuntai Zhang,Xiang Liu 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.77 No.5

To study the vibration characteristics of a high-speed railway continuous girder bridge-track coupling system (HSRCBT), a coupling vibration analysis model of an m-span continuous girder bridge-subgrade-track system with n-span approach bridge was established. The model was based on the energy and its variational method, where both the interlaminar slip and shear deformation effects were considered. In addition, the free vibration equations and natural boundary conditions of the HSRCBT were derived. Further, according to the coordination principle of deformation and mechanics, an analytical method for calculating the natural vibration frequencies of the HSRCBT was obtained. Three typical bridge-subgrade-track coupling systems of high-speed railway were taken and the results of finite element analysis were compared to those of the analytical method. The errors between the simulation results and calculated values of the analytical method were less than 3%, thus verifying the analytical method proposed in this paper. Finally, the analytical method was used to investigate the influence of the number of the approach bridge spans and the interlaminar stiffness on the natural vibration characteristics of the HSRCBT based on the degree of sensitivity. The results suggest the approach bridges have a critical number of spans and in general, the precision requirements of the analysis could be met by using 6-span approach bridges. The interlaminar vertical compressive stiffness has very little influence on the low-order natural vibration frequency of HSRCBT, but does have a significant influence on higher-order natural vibration frequency. As the interlaminar vertical compressive stiffness increases, the degree of sensitivity to interlaminar stiffness of each of the HSRCBT natural vibration characteristics decrease and gradually approach zero.

Improved Analytical Method to Investigate the Dynamic Characteristics of Composite Box Beam with Corrugated Webs

Yulin Feng,Lizhong Jiang,Wangbao Zhou 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.1

This study establishes an improved analytical method (IAM) to investigate the dynamic characteristics of composite box beam with corrugated webs (CBBCW), and the IAM has comprehensively considered the eff ects of several factors, such as the shear lag, interfacial slip, shear deformation and rotational inertia of CBBCW in combination with the characteristics of CBBCW. Further, based on the Hamilton principle, the vibration diff erential equation and boundary conditions for CBBCW have been deduced. Finally, an IAM for calculating the dynamic characteristics of CBBCW was proposed. Based on the IAM developed in this study, the natural frequencies of multiple CBBCW cases with diff erent spans, shear connection degrees and boundary conditions have been calculated. The results calculated by the IAM have been compared with those calculated by the fi nite element method and by the general beam theory. The comparison verifi es the eff ectiveness of the IAM and obtains some conclusions that are meaningful to engineering design, i.e. the shear lag eff ect of CBBCW increases with increasing shear connection degree and also increases with increasing order of the vibration mode, the shear lag eff ect of the CBBCW is up to 6.2% in the fi rst fi ve orders of the vibration modes and the eff ect cannot be ignored. In the fi rst- and second-order vibration modes of the CBBCW cases, the maximum interface slip eff ect of CBBCW is 28.42% and therefore cannot be ignored. On the other hand, the shear lag eff ect of CBBCW is usually lower than those of ordinary composite box beam with the same web thickness.

An analytical solution to the mapping relationship between bridge structures vertical deformation and rail deformation of high-speed railway

Yulin Feng,Lizhong Jiang,Wangbao Zhou,Zhipeng Lai,Xilin Chai 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.33 No.2

This paper describes a study of the mapping relationship between the vertical deformation of bridge structures and rail deformation of high-speed railway, taking the interlayer interactions of the bridge subgrade CRTS II ballastless slab track system (HSRBST) into account. The differential equations and natural boundary conditions of the mapping relationship between the vertical deformation of bridge structures and rail deformation were deduced according to the principle of stationary potential energy. Then an analytical model for such relationship was proposed. Both the analytical method proposed in this paper and the finite element numerical method were used to calculate the rail deformations under three typical deformations of bridge structures and the evolution of rail geometry under these circumstances was analyzed. It was shown that numerical and analytical calculation results are well agreed with each other, demonstrating the effectiveness of the analytical model proposed in this paper. The mapping coefficient between bridge structure deformation and rail deformation showed a nonlinear increase with increasing amplitude of the bridge structure deformation. The rail deformation showed an obvious "following feature"; with the increase of bridge span and fastener stiffness, the curve of rail deformation became gentler, the track irregularity wavelength became longer, and the performance of the rail at following the bridge structure deformation was stronger.

Post-earthquake track irregularity spectrum of high-speed railways continuous girder bridge

Yulin Feng,Lizhong Jiang,Wangbao Zhou,Mengcheng Chen 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.40 No.3

To study the track irregularity spectrum for CRTS II ballastless track continuous girder bridge for high-speed railway (CBTCGB) after the action of earthquake, a line-bridge integration seismic calculation model was established. By considering the randomness of structural parameters and ground motion, large amounts of samples were analyzed for additional track irregularity caused by factors such as earthquake-induced damage and earthquake-induced void of key components between the layers of track-bridge system. Using improved Blackman-Turkey method and Levenberg- Marquardt algorithm, the earthquake damaged CBTCGB track irregularity spectrum, track irregularity spectrogram, and a fitting formula for track irregularity spectrum after the action of near-field earthquake were obtained, and the calculation results obtained from the fitting formula and CBTCGB numerical model were compared. The results indicate that the probability sampling distribution of ground motion and structural parameters selected according to “binning method” can effectively reflect the randomness of ground motion and structural parameters. The track irregularity spectrum line forms can be roughly divided into three ranges, namely, high-frequency, medium-frequency, and low-frequency waveband. The tracks suffer more track irregularity diseases with high-frequency after earthquake, which is necessary to conduct tracking analysis. It is rational to use a three-segment power function for the fitting of track irregularity spectrum after the action of earthquake.

An Analysis Framework for Characterization of Electrical Power Data in Machining

Yulin Wang,Yan He,Yufeng Li,Ping Yan,Libin Feng 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

Electrical power data of machining has become more and more vital due to the increasing concerns on the energy efficiency. As a kind of easily available real-time signal, electrical power data in machining involves diverse characteristics related to technical specification and operational production of machine tools and workpieces. To efficiently exploit the various characteristics involved in electrical power data, this paper proposes a framework to analyze characteristics of electrical power data in machining. Firstly, the sample experiment for turning the round stock on a lathe is carried out to investigate the characteristics implied in the real-time electrical power data. Based on it, a framework is derived to analyze characteristics from three aspects, energy-specific characteristic of machining, state-specific characteristic of machine tools and operation-specific characteristic of workpieces. The case with three scenarios is presented to demonstrate the potential applications of the framework, which is effectively utilized in analyzing energy consumption of machining, monitoring states of machine tools and automatically identifying the types of machining workpieces.

The combination of deoxynivalenol and zearalenone at permitted feed concentrations causes serious physiological effects in young pigs

Feng Chen,Yulin Ma,Chunyi Xue,Jingyun Ma,Qingmei Xie,Genhu Wang,Yingzuo Bi,Yongchang Cao 대한수의학회 2008 JOURNAL OF VETERINARY SCIENCE Vol.9 No.1

This study was to investigate the effects of the combination of deoxynivalenol (DON) and zearalenone (ZON) on pigs. Twenty-four weaning piglets were divided into a control group fed a diet free of mycotoxins and a toxin group fed a diet containing 1 mg/kg DON and 250 μg/kg ZON. The results showed that supplementation of DON and ZON in diets had extensive effects on pigs. More specifically, DON and ZON caused levels of total protein, albumin, and globulin in sera to decrease (p < 0.05) by 14.5%, 6.5% and 11.3%, respectively, and at the same time increased (p < 0.05) the serum enzyme activities of γ-glutamyltransferase, aspartate aminotransferase and alanine aminotransferase by 72.0%, 32.6% and 36.6%, respectively. In addition, DON and ZON decreased (p < 0.05) the level of anticlassical swine fever antibody titers by 14.8%. Real-time PCR showed that DON and ZON caused the mRNA expression levels of IFN-γ, TNF-α, IL-2, to decrease (p < 0.05) by 36.0%, 29.0% and 35.4%, respectively. Histopathological studies demonstrated that DON and ZON caused abnormalities in the liver, spleen, lymph nodes, uterus, and kidney. The concentrations of DON and ZON used in this study are in line with the published critical values permitted by BML. Our study clearly put the standard and adequacy of safety measures for these toxins into question. The authors suggest that with the increasing availability of cellular and molecular technologies, it is time to revisit the safety standards for toxins in feeds so as to make feeds safer, providing consumers with safer products. This study was to investigate the effects of the combination of deoxynivalenol (DON) and zearalenone (ZON) on pigs. Twenty-four weaning piglets were divided into a control group fed a diet free of mycotoxins and a toxin group fed a diet containing 1 mg/kg DON and 250 μg/kg ZON. The results showed that supplementation of DON and ZON in diets had extensive effects on pigs. More specifically, DON and ZON caused levels of total protein, albumin, and globulin in sera to decrease (p < 0.05) by 14.5%, 6.5% and 11.3%, respectively, and at the same time increased (p < 0.05) the serum enzyme activities of γ-glutamyltransferase, aspartate aminotransferase and alanine aminotransferase by 72.0%, 32.6% and 36.6%, respectively. In addition, DON and ZON decreased (p < 0.05) the level of anticlassical swine fever antibody titers by 14.8%. Real-time PCR showed that DON and ZON caused the mRNA expression levels of IFN-γ, TNF-α, IL-2, to decrease (p < 0.05) by 36.0%, 29.0% and 35.4%, respectively. Histopathological studies demonstrated that DON and ZON caused abnormalities in the liver, spleen, lymph nodes, uterus, and kidney. The concentrations of DON and ZON used in this study are in line with the published critical values permitted by BML. Our study clearly put the standard and adequacy of safety measures for these toxins into question. The authors suggest that with the increasing availability of cellular and molecular technologies, it is time to revisit the safety standards for toxins in feeds so as to make feeds safer, providing consumers with safer products.

Vibration characteristic analysis of high-speed railway simply supported beam bridge-track structure system

Lizhong Jiang,Yulin Feng,Wangbao Zhou,Binbin He 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.31 No.6

Based on the energy-variational principle, a coupling vibration analysis model of high-speed railway simply supported beam bridge-track structure system (HSRBTS) was established by considering the effect of shear deformation. The vibration differential equation and natural boundary conditions of HSRBTS were derived by considering the interlayer slip effect. Then, an analytic calculation method for the natural vibration frequency of this system was obtained. By taking two simply supported beam bridges of high-speed railway of 24 m and 32 m in span as examples, ANSYS and MIDAS finite-element numerical calculation methods were compared with the analytic method established in this paper. The calculation results show that two of them agree well with each other, validating the analytic method reported in this paper. The analytic method established in this study was used to evaluate the natural vibration characteristics of HSRBTS under different interlayer stiffness and length of rails at different subgrade sections. The results show that the vertical interlayer compressive stiffness had a great influence on the high-order natural vibration frequency of HSRBTS, and the effect of longitudinal interlayer slip stiffness on the natural vibration frequency of HSRBTS could be ignored. Under different vertical interlayer stiffness conditions, the subgrade section of HSRBTS has a critical rail length, and the critical length of rail at subgrade section decreases with the increase in vertical interlayer compressive stiffness.

Analysis on natural vibration characteristics of steel-concrete composite truss beam

Lizhong Jiang,Yulin Feng,Wangbao Zhou,Binbin He 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.26 No.1

In order to study the natural vibration characteristics of steel-concrete composite truss beam (SCCTB), the influence of multiple factors such as interface slip, shear deformation and moment of inertia are considered. Afterwards, based on the Hamilton principle the vibration control differential equation and natural boundary conditions of SCCTB are deduced. By solving SCCTB differential equations of vibration control, an analytical calculation method is proposed for analyzing the natural vibration characteristics of SCCTB. The natural frequencies of SCCTBs with different degrees of shear connection and effective lengths are calculated by using the analytical method, and the results are compared against those obtained from ANSYS finite element numerical calculation method. The results show that the analytical method considering the influence factors such as interface slip, shear deformation and moment of inertia are in good agreement with those obtained from ANSYS finite element numerical calculation method. This evidences the correctness of the analytical method and show that the method proposed exhibits improvement over the previously developed theories for the natural vibration characteristics of SCCTB. Finally, based on the analytical method, the influence factors of SCCTB natural vibration characteristics are analyzed. The results indicate that the influence of interface slip stiffness on SCCTB's natural frequency is more than 10% and therefore cannot be neglected. Moreover, shear deformation has an effect of more than 35% on SCCTB’s natural frequency and the effect cannot be ignored either in this case too.

Digitally Current Controlled DC-DC Switching Converters Using an Adjacent Cycle Sampling Strategy

Tingcun Wei,Yulin Wang,Feng Li,Nan Chen,Jia Wang 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.1

A novel digital current control strategy for digitally controlled DC-DC switching converters, referred to as Adjacent Cycle Sampling (ACS), is proposed in this paper. For the ACS current control strategy, the available time interval from sampling the current to updating the duty ratio, is approximately one switching cycle. In addition, it is independent of the duty ratio. As a result, the contradiction between the processing speed of the hardware and the transient response speed can be effectively relaxed by using the ACS current control strategy. For digitally controlled buck DC-DC switching converters with trailing-edge modulation, digital current control algorithms with the ACS control strategy are derived for three different control objectives. These objectives are the valley, average, and peak inductor currents. In addition, the sub-harmonic oscillations of the above current control algorithms are analyzed and eliminated by using the digital slope compensation (DSC) method. Experimental results based on a FPGA are given, which verify the theoretical analysis results very well. It can be concluded that the ACS control has a faster transient response speed than the time delay control, and that its requirements for hardware processing speed can be reduced when compared with the deadbeat control. Therefore, it promises to be one of the key technologies for high-frequency DC-DC switching converters.

Digitally Current Controlled DC-DC Switching Converters Using an Adjacent Cycle Sampling Strategy

Wei, Tingcun,Wang, Yulin,Li, Feng,Chen, Nan,Wang, Jia The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.1

A novel digital current control strategy for digitally controlled DC-DC switching converters, referred to as Adjacent Cycle Sampling (ACS), is proposed in this paper. For the ACS current control strategy, the available time interval from sampling the current to updating the duty ratio, is approximately one switching cycle. In addition, it is independent of the duty ratio. As a result, the contradiction between the processing speed of the hardware and the transient response speed can be effectively relaxed by using the ACS current control strategy. For digitally controlled buck DC-DC switching converters with trailing-edge modulation, digital current control algorithms with the ACS control strategy are derived for three different control objectives. These objectives are the valley, average, and peak inductor currents. In addition, the sub-harmonic oscillations of the above current control algorithms are analyzed and eliminated by using the digital slope compensation (DSC) method. Experimental results based on a FPGA are given, which verify the theoretical analysis results very well. It can be concluded that the ACS control has a faster transient response speed than the time delay control, and that its requirements for hardware processing speed can be reduced when compared with the deadbeat control. Therefore, it promises to be one of the key technologies for high-frequency DC-DC switching converters.