Stability Analysis of Multibody Systems With Long Flexible Bodies Using the Moving Modes Method and Its Application to Railroad Dynamics

Ensuring the safety of the railway vehicles over bridges shaken by earthquakes is a practical issue in the seismic design of railway bridges. To improve the vehicle’s running safety on railway bridges during earthquakes, the stopper (or bump-stop) between the bogie and the car-body of the vehicle was modified as a fuse-type element, i.e., it was designed to break under large impact due to earthquake occurrence. The efficacy of the fuse stopper was illustrated by a full-scale vehicle-track shake table test. The fuse stopper element was introduced to the vehicle-bridge interaction model, whose accuracy was also demonstrated by comparison with the test results. The fuse stopper was designed to remain intact under service level earthquakes (SLE) to avoid frequent replacement or repair, while it should fuse to improve vehicle safety on a group of bridges under design basis earthquakes (DBE). The bridge group includes 24 simply-supported bridges with pier heights ranging from 6m to 60m, covering the most simply-supported bridges in the China railway network. A total of 10 ground motion records were used in the analysis to account for the uncertainty of ground motions. Through vehicle-bridge incremental dynamic analysis (IDA) simulation, the optimal fusion strength of 188 kN and the extended gap of 0.04 m were proposed for the fuse stopper at DBE intensity, in which the bridge group can achieve derailment-free. The design procedure of the fuse stopper may provide a cost-effective way to improve the vehicle’s running safety on a group of bridges during earthquakes.

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“…The mass, stiffness and damping of this oscillator can be obtained by the Rayleigh-Ritz method. 17 The EOM of the rail can be written as…”

Section: Vehicle-track Modelmentioning

confidence: 99%

Improving running safety of railway bridges during earthquakes by equipping vehicle with lateral fuse stopper

Jin

Chen

2023

Proceedings of the Institution of Mechanical Engineers, Part F:

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“…Fragility analysis for vehicle derailment on railway bridges under earthquakes 1 3 similar to the moving section simplification in Refs. [25,26]. This method uses the steady deflection of the rail induced by a concentrated force P as the shape function of the rail (see Fig.…”

Section: Fig 1 Vehicle-bridge Interaction Modelmentioning

confidence: 99%

“…The oscillator has two DOFs: lateral and vertical. The modal mass M rv , modal damping C rv and modal stiffness K rv in the vertical direction are calculated by the Rayleigh-Ritz method [25], and the modal mass M rh , modal damping C rh and modal stiffness K rh in the lateral direction can be derived in a parallel way. Then, the mass M r , damping C r , and stiffness K r of this oscillator are obtained:…”

Section: Fig 1 Vehicle-bridge Interaction Modelmentioning

confidence: 99%

Fragility analysis for vehicle derailment on railway bridges under earthquakes

Jin

Liu

2022

Rail. Eng. Science

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With the rapid development of high-speed railways around the globe, the safety of vehicles running on bridges during earthquakes has been paid more attention to. In the design of railway bridges, in addition to ensuring the safety of the bridge structure in earthquake, the vehicle safety should also be ensured. Previous studies have focused on the detailed analysis of vehicle derailment on bridges, proposing complex numerical algorithms for wheel–rail contact analysis as well as for parametric analysis, but they are inconvenient for designers. Intensity measure (IM) used in performance-based earthquake engineering is introduced in this study. A method to evaluate the vehicle safety on bridges under earthquakes is proposed with respect to the optimal IM. Then, the vehicle derailment case of the Kumamoto earthquake in Japan verifies the decoupling method of vehicle–bridge interaction model. In the assessment of vehicle derailments, eight IMs are systematically compared: the IMs of bridge deck motion are generally better than those of ground motion; the variation coefficient of spectral intensity of the bridge deck is the smallest at different frequencies. Finally, the derailment fragility cloud map is presented to evaluate the vehicle safety on bridges during earthquakes.

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“…This study idealizes the track structure beneath each wheel as a single-DOF oscillator similar to the moving section model (Chamorro et al, 2014). This model is obtained by the Rayleigh–Ritz method by expressing the rail deflection u R ( x , t ) as the product of the generalized coordinate Y R ( t ) and the trial function (or shape function) ϕ R ( x ) …”

Section: Simplification Of Vehicle–track Modelsmentioning

confidence: 99%

Efficient evaluation of bridge deformation for running safety of railway vehicles using simplified models

Jin

Yuan

Pei

2019

Advances in Structural Engineering

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The running safety of high-speed trains over bridges is a great concern in bridge design. Typically, the running safety of vehicles is evaluated by vehicle–track simulations that are computationally expensive and unfamiliar to bridge designers. This study investigates simplified vehicle–track models for assessing the running safety of vehicles on deformed bridges. Four types of simplified vehicle models along with four types of simplified wheel–track models are investigated. The predicted wheel–rail forces are compared with those simulated by the detailed vehicle–track program. In these simulations, typical bridge deformations are taken as excitations to the dynamic system. It is found that omitting the rail vibration leads to large wheel–rail response errors. The wheel–rail constraint model gives similar wheel–rail responses to those obtained by the Hertz contact model. A vehicle–track model with five degrees-of-freedom is adequate for assessing wheel–rail forces. Furthermore, an analytical solution to the wheel–rail forces running over an angular rotation was obtained. These simplified vehicle–track models provide an efficient way to assess the running safety of vehicles on deformed bridges when using probabilistic or optimal analyses that require a large number of simulations.

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Stability Analysis of Multibody Systems With Long Flexible Bodies Using the Moving Modes Method and Its Application to Railroad Dynamics

Cited by 10 publications

References 19 publications

Improving running safety of railway bridges during earthquakes by equipping vehicle with lateral fuse stopper

Improving running safety of railway bridges during earthquakes by equipping vehicle with lateral fuse stopper

Fragility analysis for vehicle derailment on railway bridges under earthquakes

Efficient evaluation of bridge deformation for running safety of railway vehicles using simplified models

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