scholarly journals Analysis on the Stress State of Cast Aluminum Beam of High Speed Train Based on Rigid-flexible Coupling Dynamic Model

2020 ◽  
Vol 56 (2) ◽  
pp. 138
Author(s):  
DOU Weiyuan ◽  
ZHANG Lele ◽  
ZHANG Haifeng ◽  
LIU Changqing
Keyword(s):  
Stress State ◽  
Dynamic Model ◽  
High Speed ◽  
High Speed Train ◽  
Cast Aluminum ◽  
Flexible Coupling ◽  
Coupling Dynamic ◽  
Aluminum Beam ◽  
Coupling Dynamic Model

Effects of High-Speed Railway in Tunnel on Vibration Response of Upper Building

2013 ◽  
Vol 482 ◽  
pp. 155-162
Author(s):  
Si Hui Xu ◽  
Xiao Hui Zhang ◽  
Han Chen
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Reaction Force ◽  
Element Model ◽  
Vibration Response ◽  
Vibration Level ◽  
High Speed Railway ◽  
Proper Distance ◽  
Coupling Dynamic ◽  
Coupling Dynamic Model

In order to study the effects of high-speed railway in tunnel on vibration response of upper building, the Vehicle-Track-Tunnel-Soil-Building coupling dynamic model was established, and the reaction force of fasteners was used to transmit between Vehicle-Track coupling dynamic model and Tunnel-Soil-Building finite element model. According to modal analysis for typical section of building, sensitive frequency range and sensitive structure locations were obtained. In terms of two conditions, Tunnel-Building Integrated Structure and building are evaded from tunnel for some distance, 1/3 octave vibration level and VLZ vibration acceleration level for all measuring points were calculated to analyze the vibration response of building. The results are shown as follows: for Tunnel-Building Integrated Structure, the overall vibration level is high,which is above 65dB. 2-3dB will be reduced by decreasing speed and improving standard of track. when building is evaded from tunnel for some distance, with larger evaded distance, the vibration response is slighter. However, when evaded distance is above 30m, vibration may be amplified ,so its necessary to select proper distance. Vibration response of structure is most strong when 4 lines meet under building, so strict limitation on meeting condition of trains can effectively reduce vibration level.

A direct method-based strength evaluation of the cast aluminum beam used in a high-speed train

2019 ◽  
Vol 233 (9) ◽  
pp. 896-905
Author(s):  
Songhua Huang ◽  
Yugong Xu ◽  
Alexander Bezold ◽  
Lele Zhang ◽  
Geng Chen ◽  
...  
Keyword(s):  
High Speed ◽  
Direct Method ◽  
Weight Ratio ◽  
Rolling Stock ◽  
High Speed Train ◽  
Cast Aluminum ◽  
Aluminum Casting ◽  
Beam Structure ◽  
Aluminum Beam ◽  
A Direct Method

In this paper, the authors elaborate how numerical techniques developed from the direct method can be used to predict the load-bearing capacity of the aluminum casting beam structure which is presently used in the Chinese high-speed train CRH5A. The numerical method introduced in this paper is formulated based on the Melan's static theorem; thus, it determines the strength of the cast aluminum beam under both monotonic and cyclic loads without following the entire load profile. In addition to constructing the plastic and shakedown limits of the component, the proposed approach is also employed to study how stiffeners' thickness on the key areas influences the feasible load domains. Based on the intensive sensitivity analysis, an optimal thickness has been determined which gives the highest strength-to-weight ratio. To this end, the paper confirms that the direct method is a viable means for designing structures used in the rolling stock.

scholarly journals Rigid-flexible coupling dynamic model of a flexible planar parallel robot for modal characteristics research

2019 ◽  
Vol 11 (1) ◽  
pp. 168781401882346 ◽  
Author(s):  
Lianchao Sheng ◽  
Wei Li ◽  
Yuqiao Wang ◽  
Xuefeng Yang ◽  
Mengbao Fan
Keyword(s):  
Mathematical Model ◽  
Dynamic Model ◽  
High Speed ◽  
Control Program ◽  
Parallel Robot ◽  
Elastic Vibration ◽  
Parallel Robots ◽  
Flexible Coupling ◽  
Dynamic Mathematical Model ◽  
Coupling Dynamic

The increasing applications of flexible parallel robots in industrial production have presented the advantages of light weight and high speed, but at the same time, the elastic vibration problem has emerged. By investigating the modal features of flexible parallel robots so as to suppress the elastic vibration, with pinned-pinned as flexible intermediate links boundary conditions, this article analyzes the rigid-flexible coupling dynamic mathematical model of the 3-RRR (3-Rotate-Rotate-Rotate) flexible planar parallel robot with flexible intermediate links. The effect of the extremity concentrated rotation inertia of flexible intermediate links is considered in the mathematical model. Besides, the effect of inertia and coupling force on the dynamic model and the first three-order vibration responses of flexible intermediate links were discussed based on the established model. The corresponding spectrum characteristics were studied using fast Fourier transform. Comparing the frequency characteristics obtained by theoretical model and modal experiment, it was found that the results obtained by the dynamic mathematical model are quite close to the test results. Less dynamic parameters make it convenient to carry out the control program.

scholarly journals Fatigue Characterization on a Cast Aluminum Beam of a High-Speed Train Through Numerical Simulation and Experiments

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Weiyuan Dou ◽  
Lele Zhang ◽  
Haifeng Chang ◽  
Haifeng Zhang ◽  
Changqing Liu
Keyword(s):  
Finite Element ◽  
Fatigue Strength ◽  
Stress Concentration ◽  
High Speed ◽  
Fatigue Property ◽  
Strength Reduction ◽  
High Speed Train ◽  
Cast Aluminum ◽  
Structural Fatigue ◽  
Aluminum Beam

AbstractThe cast aluminum beam is a key structure for carrying the body-hung traction motor of a high-speed train; its fatigue property is fundamental for predicting the residual life and service mileage of the structure. To characterize the structural fatigue property, a finite element-based method is developed to compute the stress concentration factor, which is used to obtain the structural fatigue strength reduction factors. A full-scale fatigue test on the cast aluminum beam is designed and implemented for up to ten million cycles, and the corresponding finite element model of the beam is validated using the measured data of the gauges. The results show that the maximum stress concentration occurs at the fillet of the supporting seat, where the structural fatigue strength reduction factor is 2.45 and the calculated fatigue limit is 35.4 MPa. Moreover, no surface cracks are detected using the liquid penetrant test. Both the experimental and simulation results indicate that the cast aluminum beam can satisfy the service life requirements under the designed loading conditions.

Rigid–flexible coupling dynamics analysis with joint clearance for a 5-DOF hybrid polishing robot

Robotica ◽  
2021 ◽  
pp. 1-21
Author(s):  
Feng Guo ◽  
Gang Cheng ◽  
Shilin Wang ◽  
Jun Li
Keyword(s):  
Dynamic Model ◽  
Parallel Manipulator ◽  
Dynamic Properties ◽  
Dynamic Performance ◽  
Joint Clearance ◽  
Motion Error ◽  
Flexible Coupling ◽  
Coupling Dynamic ◽  
Equivalent Load ◽  
Coupling Dynamic Model

SUMMARY Considering the polishing requirements for high-precision aspherical optical mirrors, a hybrid polishing robot composed of a serial–parallel manipulator and a dual rotor grinding system is proposed. Firstly, based on the kinematics of serial components, the equivalent load model for the parallel manipulator is established. Then, the elastodynamic model of kinematic branched-chains of the parallel manipulator is established by using the spatial beam element, and the rigid–flexible coupling dynamic model of the polishing robot is obtained with Kineto-elasto dynamics theory. Further, considering the dynamic properties of the joint clearance, the rigid–flexible coupling dynamic model with the joint clearance for the polishing robot is established. Finally, the equivalent load distribution of the parallel manipulator is analyzed, and the effect of the branched-chain elasticity and joint clearance on the motion error of the polishing robot is studied. This article provides a theoretical basis for improving the motion accuracy and dynamic performance of the hybrid polishing robot.

Vibration analysis of a flexible gearbox system considering a local fault in the outer ring of the supported ball bearing

2020 ◽  
pp. 107754632093688
Author(s):  
Jing Liu ◽  
Lei Yuan
Keyword(s):  
Dynamic Model ◽  
Transmission System ◽  
Gear Transmission ◽  
Ball Bearings ◽  
Transmission Characteristics ◽  
Flexible Coupling ◽  
Flexible Shaft ◽  
Gear Transmission System ◽  
Coupling Dynamic ◽  
Coupling Dynamic Model

Ball bearings are key components in the gear transmission system. Supported ball bearings have great influences on the vibrations of the gear transmission system, especially the presence of the local faults. Although some reported works formulated the local fault in the supported bearings of the gear transmission system, the box and shaft were considered as rigid bodies. To overcome this problem, a rigid-flexible coupling dynamic model for a flexible gearbox with the supported ball bearings is developed, which cannot be described by the previous multibody models. The local fault in the supported bearing is described by a time-varying impact force model with a half-sine profile. The bearing clearance, flexible shaft, and box are considered in the rigid-flexible coupling dynamic model. The flexible shaft and box are formulated by a finite element method. The damping and contact stiffness in the bearings and gears are obtained by the previous methods in the listed works. The frictions between the mating components are formulated by the Coulomb friction model. An experimental study is applied to validate the rigid-flexible coupling dynamic model. The effects of the faults on the vibration transmission characteristics are investigated. The results provide that the local fault in the supported bearings will greatly affect the vibrations of the gearbox system. Moreover, it depicts that the vibration collection point for the defective bearings should be located at the same side to obtain better singles. This work can provide a more reasonable method for understanding the vibration transmission characteristics of the gearbox system with the local faults in the supported bearings than the reported multibody models.

Dynamic Simulation Analysis of Shipborne Missile Launching under High-Wave-Level Environment

2012 ◽  
Vol 569 ◽  
pp. 380-385
Author(s):  
Zhou Zhong ◽  
Yi Jiang ◽  
Yong Yuan Li ◽  
Chong Zhang
Keyword(s):  
Dynamic Response ◽  
Dynamic Model ◽  
Dynamic Simulation ◽  
Simulation Analysis ◽  
Simulation Method ◽  
Flexible Coupling ◽  
High Wave ◽  
Model And Simulation ◽  
Coupling Dynamic ◽  
Coupling Dynamic Model

In order to study the dynamic response of shipborne missile vertical launching under high-wave-level environment, the rigid-flexible coupling dynamic model of launching system was built by ways of virtual prototype technology. According to simulations for different launching conditions, missile attitude parameters were acquired, and interference of various parts was analyzed. The result shows that the dynamic model and simulation method proposed in this paper are effective and practicable.

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