To explore the impact of wheel-rail excitation on the dynamic performance of axle box bearings,a dynamic model of the high-speed train including axle box bearings is developed.Subsequently,the dynamic response charact...To explore the impact of wheel-rail excitation on the dynamic performance of axle box bearings,a dynamic model of the high-speed train including axle box bearings is developed.Subsequently,the dynamic response characteristics of the axle box bearing are examined.The investigation focuses on the acceleration characteristics of bearing vibration under excitation of track irregularities and wheel flats.In addition,experiments on both normal and faulty bearings are conducted separately,and the correctness of the model and some conclusions are verified.According to the research,track irregularity is unfavorable for bearing fault detection based on resonance demodulation.Under the same speed conditions,the acceleration peak of bearing is inversely proportional to the length of the wheel flat and directly proportional to its depth.The paper will contribute to a deeper understanding of the dynamic performance of axle box bearings.展开更多
A new lightweight high-speed stacker is designed and developed.Its technical parameters are leading the industry level,which can meet the current requirements for high efficiency of intelligent logistics system.Starti...A new lightweight high-speed stacker is designed and developed.Its technical parameters are leading the industry level,which can meet the current requirements for high efficiency of intelligent logistics system.Starting from the key structure of stacker,through the theoretical analysis of the new mechanism and the comparison of the new and old equipment,the advantages of the new mechanism in improving the efficiency and lightweight design of stacker are explained.Through ANSYS Workbench finite element software,the structural strength of the main bearing mechanism is analyzed,and the results show that the strength meets the requirements.展开更多
In this study, the separation and drying efficiency of the excreta, separated into solid and liquid fraction by a flat conveyor belt under a partial slatted floor in a facility for fattening pigs, was determined. Two ...In this study, the separation and drying efficiency of the excreta, separated into solid and liquid fraction by a flat conveyor belt under a partial slatted floor in a facility for fattening pigs, was determined. Two transverse slope angles (4° and 6°) for the flat belts were used, in a trial with pigs from 20.61 to 117.83 kg of live weight (LW), and the sample size was 7 pigs per pen, 42 pigs per room. The flat belt was more efficient with 6° than with 4° slope angle (32.65% vs. 29.91% dry matter content of solid fraction during the whole fattening period, respectively;P ° than for the 4° (1.4137 vs. 1.3030, during the whole fattening period;P °, this efficiency was not improved in finishing period -83.40 to 117.83 kg LW (two extractions per day) with regard to the growth period -20.61 to 83.40 kg LW (one extraction per day). Meanwhile, with 4° it did improved. The ventilation system underneath slat seems to play a key role in the obtained results.展开更多
When applying fiat belts, correct tracking of the belt through the installation has to be assured. Since flat belts are commonly used for conveying and transmission purposes, tracking systems have been well developed,...When applying fiat belts, correct tracking of the belt through the installation has to be assured. Since flat belts are commonly used for conveying and transmission purposes, tracking systems have been well developed, but the ultimate tracking behaviour of the belt can be greatly enhanced by taking special care in the creation of an adequate tracking mechanism. To obtain long-life operation and full value from the equipment, the correct tracking technique plays an important role. This paper deals with two tracking techniques： The skewed and the angled pulley axis. Numerical simulation results are compared with both measurements and an analytical approach. The advantages of numerical simulation compared to experimental tests are ease, convenience and the absence of any safety risk. Compared to analytical approaches the simulation is used for systems for which simple closed form analytic solutions are not possible.展开更多
A three-dimensional （3-D） wheel-rail rolling contact model with a wheel fiat was built using commercial software Hypermesh, and the dynamic finite element simulation was conducted using LS-DYNA 3D/explicit code. Inf...A three-dimensional （3-D） wheel-rail rolling contact model with a wheel fiat was built using commercial software Hypermesh, and the dynamic finite element simulation was conducted using LS-DYNA 3D/explicit code. Influences of the train speed, flat length and axle load on the vertical wheel-rail impact response were discussed, respectively. The results show that the maximum vertical wheel-rail impact force induced by the wheel flat is higher than that generated by the perfect wheel, and these two dynamic impact forces are much greater than the static axle load. Besides, the maximum von Mises equivalent stress and maximum equivalent plastic strain are observed on the wheel-rail contact surface, and both of them as well as the maximum wheel-rail impact force are sensitive to train speed, fiat length and axle load.展开更多
A transportation hub is the key link in the construction of the comprehensive three-dimensional transportation corridor of the Yangtze River Economic Belt,and is the basic factor responsible for the promotion of this ...A transportation hub is the key link in the construction of the comprehensive three-dimensional transportation corridor of the Yangtze River Economic Belt,and is the basic factor responsible for the promotion of this belt.A high-speed railway hub has the“last kilometer of time-space compression”effect and is the key to building an efficient,convenient,modern,and comprehensive transportation system.This study constructed a model for measuring the connection-distribution performance of the high-speed railway hub,determined the connection-distribution performance of the urban high-speed railway hub in the Yangtze River Economic Belt,and analyzed its spatial differentiation characteristics,further revealed the influencing mechanism of the connection-distribution performance of the high-speed railway hub.The main results are as follows:(1)The connection-distribution performance of the high-speed railway hub in the Yangtze River Economic Belt presented an“olive-shaped pattern”grade structure with two small ends and a large middle section,that is,the number of high-speed railway stations with high performance and average performance was small,and the number of high-speed railway stations with good performance and medium performance was large.(2)The connection-distribution performance of the high-speed railway hub in the Yangtze River Economic Belt showed a regional differentiation pattern of“high in the east and low in the west”and“high in the north and low in the south”,and showed an urban agglomeration differentiation pattern of“high in the core areas but low in the marginal areas”;moreover,spatial differences were prominent in the distribution of nine evaluation indexes of the connection-distribution performance of the high-speed railway hub.(3)GDP,urbanization rate,city level,station passenger flow and frequency of shuttle bus were key driving factors affecting the connection-distribution performance of the high-speed railway hub.At the same time,there were significant differences in the key driving factors for the connection-distribution performance grades of high-quality,good,medium and average.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.12393780,1203201712002221)+3 种基金the Key Scientific Research Projects of China Railway Group(No.N2021J032)the College Education Scientific Research Project in Hebei Province of China(No.JZX2024006)the S&T Program in Hebei of China(No.21567622H)the Research Project of Hebei Province Science and Technology(No.QN2023071)。
文摘To explore the impact of wheel-rail excitation on the dynamic performance of axle box bearings,a dynamic model of the high-speed train including axle box bearings is developed.Subsequently,the dynamic response characteristics of the axle box bearing are examined.The investigation focuses on the acceleration characteristics of bearing vibration under excitation of track irregularities and wheel flats.In addition,experiments on both normal and faulty bearings are conducted separately,and the correctness of the model and some conclusions are verified.According to the research,track irregularity is unfavorable for bearing fault detection based on resonance demodulation.Under the same speed conditions,the acceleration peak of bearing is inversely proportional to the length of the wheel flat and directly proportional to its depth.The paper will contribute to a deeper understanding of the dynamic performance of axle box bearings.
文摘A new lightweight high-speed stacker is designed and developed.Its technical parameters are leading the industry level,which can meet the current requirements for high efficiency of intelligent logistics system.Starting from the key structure of stacker,through the theoretical analysis of the new mechanism and the comparison of the new and old equipment,the advantages of the new mechanism in improving the efficiency and lightweight design of stacker are explained.Through ANSYS Workbench finite element software,the structural strength of the main bearing mechanism is analyzed,and the results show that the strength meets the requirements.
文摘In this study, the separation and drying efficiency of the excreta, separated into solid and liquid fraction by a flat conveyor belt under a partial slatted floor in a facility for fattening pigs, was determined. Two transverse slope angles (4° and 6°) for the flat belts were used, in a trial with pigs from 20.61 to 117.83 kg of live weight (LW), and the sample size was 7 pigs per pen, 42 pigs per room. The flat belt was more efficient with 6° than with 4° slope angle (32.65% vs. 29.91% dry matter content of solid fraction during the whole fattening period, respectively;P ° than for the 4° (1.4137 vs. 1.3030, during the whole fattening period;P °, this efficiency was not improved in finishing period -83.40 to 117.83 kg LW (two extractions per day) with regard to the growth period -20.61 to 83.40 kg LW (one extraction per day). Meanwhile, with 4° it did improved. The ventilation system underneath slat seems to play a key role in the obtained results.
文摘When applying fiat belts, correct tracking of the belt through the installation has to be assured. Since flat belts are commonly used for conveying and transmission purposes, tracking systems have been well developed, but the ultimate tracking behaviour of the belt can be greatly enhanced by taking special care in the creation of an adequate tracking mechanism. To obtain long-life operation and full value from the equipment, the correct tracking technique plays an important role. This paper deals with two tracking techniques： The skewed and the angled pulley axis. Numerical simulation results are compared with both measurements and an analytical approach. The advantages of numerical simulation compared to experimental tests are ease, convenience and the absence of any safety risk. Compared to analytical approaches the simulation is used for systems for which simple closed form analytic solutions are not possible.
基金supported by the National Natural Science Foundation of China (Grant No. 51475392)the Fundamental Research Funds for the Central Universities (Grant No. 2682015RC09)the Research Fund of State Key Laboratory of Traction Power (Grant No. 2015TPL_T02)
文摘A three-dimensional （3-D） wheel-rail rolling contact model with a wheel fiat was built using commercial software Hypermesh, and the dynamic finite element simulation was conducted using LS-DYNA 3D/explicit code. Influences of the train speed, flat length and axle load on the vertical wheel-rail impact response were discussed, respectively. The results show that the maximum vertical wheel-rail impact force induced by the wheel flat is higher than that generated by the perfect wheel, and these two dynamic impact forces are much greater than the static axle load. Besides, the maximum von Mises equivalent stress and maximum equivalent plastic strain are observed on the wheel-rail contact surface, and both of them as well as the maximum wheel-rail impact force are sensitive to train speed, fiat length and axle load.
基金The Key Project of National Natural Science Foundation of China,No.41930644。
文摘A transportation hub is the key link in the construction of the comprehensive three-dimensional transportation corridor of the Yangtze River Economic Belt,and is the basic factor responsible for the promotion of this belt.A high-speed railway hub has the“last kilometer of time-space compression”effect and is the key to building an efficient,convenient,modern,and comprehensive transportation system.This study constructed a model for measuring the connection-distribution performance of the high-speed railway hub,determined the connection-distribution performance of the urban high-speed railway hub in the Yangtze River Economic Belt,and analyzed its spatial differentiation characteristics,further revealed the influencing mechanism of the connection-distribution performance of the high-speed railway hub.The main results are as follows:(1)The connection-distribution performance of the high-speed railway hub in the Yangtze River Economic Belt presented an“olive-shaped pattern”grade structure with two small ends and a large middle section,that is,the number of high-speed railway stations with high performance and average performance was small,and the number of high-speed railway stations with good performance and medium performance was large.(2)The connection-distribution performance of the high-speed railway hub in the Yangtze River Economic Belt showed a regional differentiation pattern of“high in the east and low in the west”and“high in the north and low in the south”,and showed an urban agglomeration differentiation pattern of“high in the core areas but low in the marginal areas”;moreover,spatial differences were prominent in the distribution of nine evaluation indexes of the connection-distribution performance of the high-speed railway hub.(3)GDP,urbanization rate,city level,station passenger flow and frequency of shuttle bus were key driving factors affecting the connection-distribution performance of the high-speed railway hub.At the same time,there were significant differences in the key driving factors for the connection-distribution performance grades of high-quality,good,medium and average.
