scholarly journals Vehicle-Bridge Coupling Vibration Analysis for Simply Supported Girders of High-Speed Railway Bridges Based on the Cross-Sectional Decentralized Centre of Mass and Shear

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Chen Daihai ◽  
Zhou Shuai ◽  
Xu Shizhan ◽  
Li Zheng ◽  
Fang Yilin
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Influence Factors ◽  
Centre Of Mass ◽  
Cross Sectional ◽  
High Speed Railway ◽  
Coupling Vibration ◽  
Offset Distance ◽  
Spatial Beam ◽  
The Cross

Taking the simply supported box girder bridge of high-speed railway as an example, the effect of cross-sectional decentralized centre of mass and shear on the spatial beam element stiffness matrix was theoretically derived. Based on the vehicle-bridge coupling vibration analysis method of the railway bridge, an analysis program of vehicle-bridge coupling vibration for the high-speed railway was compiled, and its reliability was verified through an example analysis. On this basis, considering the cross-sectional decentralized centre of mass and shear, the influence factors of vehicle-bridge coupling vibration response were studied, which included the offset distance of the beam section’s mass and shear centre, offset distance of track centreline, vehicle weight, and vehicle speed. The results show that the additional items of the spatial beam element stiffness matrix are generated by the torsion effect when the cross-sectional decentralized centre of mass and shear is considered, and it will affect the lateral and vertical stiffness of the element. The cross-sectional decentralized centre of mass and shear has a significant effect on the lateral dynamic response of the bridge’s mid-span, but the influence on the vertical response of the bridge and the dynamic response of the car body is small. The main influence factors of the lateral dynamic response of the bridge are the vertical offset distance of the beam section’s centre of mass and shear, the lateral offset distance of the track centreline, and the vehicle weight.

scholarly journals Observation and analysis of diving beetle movements while swimming

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Debo Qi ◽  
Chengchun Zhang ◽  
Jingwei He ◽  
Yongli Yue ◽  
Jing Wang ◽  
...  
Keyword(s):  
Swimming Speed ◽  
High Speed ◽  
Kinematic Model ◽  
Movement Pattern ◽  
Unmanned Vehicles ◽  
Power Stroke ◽  
Cross Sectional ◽  
Motion Data ◽  
The Cross ◽  
Diving Beetle

AbstractThe fast swimming speed, flexible cornering, and high propulsion efficiency of diving beetles are primarily achieved by their two powerful hind legs. Unlike other aquatic organisms, such as turtle, jellyfish, fish and frog et al., the diving beetle could complete retreating motion without turning around, and the turning radius is small for this kind of propulsion mode. However, most bionic vehicles have not contained these advantages, the study about this propulsion method is useful for the design of bionic robots. In this paper, the swimming videos of the diving beetle, including forwarding, turning and retreating, were captured by two synchronized high-speed cameras, and were analyzed via SIMI Motion. The analysis results revealed that the swimming speed initially increased quickly to a maximum at 60% of the power stroke, and then decreased. During the power stroke, the diving beetle stretched its tibias and tarsi, the bristles on both sides of which were shaped like paddles, to maximize the cross-sectional areas against the water to achieve the maximum thrust. During the recovery stroke, the diving beetle rotated its tarsi and folded the bristles to minimize the cross-sectional areas to reduce the drag force. For one turning motion (turn right about 90 degrees), it takes only one motion cycle for the diving beetle to complete it. During the retreating motion, the average acceleration was close to 9.8 m/s2 in the first 25 ms. Finally, based on the diving beetle's hind-leg movement pattern, a kinematic model was constructed, and according to this model and the motion data of the joint angles, the motion trajectories of the hind legs were obtained by using MATLAB. Since the advantages of this propulsion method, it may become a new bionic propulsion method, and the motion data and kinematic model of the hind legs will be helpful in the design of bionic underwater unmanned vehicles.

scholarly journals Effect of Bridge-Pier Differential Settlement on the Dynamic Response of a High-Speed Railway Train-Track-Bridge System

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Xiaohui Zhang ◽  
Yao Shan ◽  
Xinwen Yang
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Tensile Force ◽  
Differential Settlement ◽  
Bridge Pier ◽  
Vertical Acceleration ◽  
Train Track ◽  
Allowable Limit ◽  
High Speed Railway ◽  
Track Bridge

A model based on the theory of train-track-bridge coupling dynamics is built in the article to investigate how high-speed railway bridge pier differential settlement can affect various railway performance-related criteria. The performance of the model compares favorably with that of a 3D finite element model and train-track-bridge numerical model. The analysis of the study demonstrates that all the dynamic response for a span of 24 m is slightly larger than that for a span of 32 m. The wheel unloading rate increases with pier differential settlement for all of the calculation conditions considered, and its maximum value of 0.695 is well below the allowable limit. Meanwhile, the vertical acceleration increases with pier differential settlement and train speed, respectively, and the values for a pier differential settlement of 10 mm and speed of 350 km/h exceed the maximum allowable limit stipulated in the Chinese standards. On this basis, a speed limit for the exceeding pier differential settlement is determined for comfort consideration. Fasteners that had an initial tensile force due to pier differential settlement experience both compressive and tensile forces as the train passes through and are likely to have a lower service life than those which solely experience compressive forces.

Quick assessment of high-speed railway bridges based on a non-dimensional parameter representation

2017 ◽  
Vol 20 (11) ◽  
pp. 1623-1631 ◽  
Author(s):  
Patrick Salcher ◽  
Christoph Adam
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Response Assessment ◽  
Engineering Practice ◽  
Characteristic Parameters ◽  
Dimensional Parameter ◽  
High Speed Railway ◽  
Railway Bridges ◽  
Parameter Representation ◽  
Bridge Model

The objective of this study is to provide the engineering practice with a tool for simplified dynamic response assessment of high-speed railway bridges in the pre-design phase. To serve this purpose, a non-dimensional representation of the characteristic parameters of the train–bridge interaction problem is described and extended based on a beam bridge model subjected to the static axle loads of the crossing high-speed train. The non-dimensional parameter representation is used to discuss several code-related design issues. It is revealed that in an admitted parameter domain, a code-regulated static assessment of high-speed railway bridges may under-predict the actual dynamic response. Furthermore, the minimum mass of a bridge as a function of the characteristic parameters is presented to comply with the maximum bridge acceleration specified in standards.

Study on Prediction Model of Shrinkage and Creep of Prestressed Concrete Beam in Passenger Dedicated Line

2011 ◽  
Vol 255-260 ◽  
pp. 3998-4002
Author(s):  
Jun Li Luo ◽  
Zhi Sheng Xu ◽  
Jun Li ◽  
Ji Hao Yang
Keyword(s):  
Prestressed Concrete ◽  
High Speed ◽  
Concrete Beam ◽  
Influence Factors ◽  
Creep Model ◽  
High Speed Railway ◽  
Modified Model ◽  
Shrinkage And Creep ◽  
Prestressed Concrete Bridge ◽  
Passenger Dedicated Line

To improve the calculation precision of deformation in prestressed concrete bridge in passenger dedicated line and accurately predict the development of shrinkage and creep in bridge, a universal applicable modified model was put forward in this paper based on ACI 209R(1992) shrinkage and creep model. In the modified model, three influence factors-slump, strength and reinforcement - are corrected. And the modified model results were compared with the experimental results. It shows that the modified model can more accurately predict the development of shrinkage and creep of high-speed railway bridge and better accord with the law of it.

Nighttime Monitoring and Assessment Technology of Subgrade Settlement for Chengdu-Guanxian Line during Operation Period

2013 ◽  
Vol 742 ◽  
pp. 13-18
Author(s):  
Qian Su ◽  
Wei Jiang ◽  
Kai Jiang ◽  
Yu Jie Li ◽  
Ling Ling Yang
Keyword(s):  
High Speed ◽  
Influence Factors ◽  
Residual Deformation ◽  
High Speed Train ◽  
High Speed Railway ◽  
Ballastless Track ◽  
Operation Period ◽  
Assessment Technology ◽  
Railway Passenger ◽  
Maintenance Plan

The criterion for residual deformation of Substructure of ballasteless track on railway passenger dedicated line is extremely strict in order to satisfy the safety and comfort requirements of the high-speed train during operation period, urgent need to strengthen the ballastless track lines settlement deformation observation, prediction and assessment technology. Based on Chengdu-Guanxian line, this paper puts forward observation programs of subgrade settlement combined with the characteristics of Subgrade Settlement through the analysis of the influence factors of subgrade settlement deformation and key consideration about the factors of nighttime observation precision. It shows that the monitoring and assessment technology could meet the requirements through the analysis of field data, it can be guidance of railway management departments to make maintenance plan. Some advices provide reference for the monitoring and assessment of high-speed railway subgrade settlement during operation period.

Sign in / Sign up

Export Citation Format

Share Document