Masamichi Sogabe

A Simple and Efficient Numerical Method for Dynamic Interaction Analysis of a High-Speed Train and Railway Structure During an Earthquake

In this paper, a simple and efficient numerical method to solve for the dynamic interaction of a high-speed train and railway structure during an earthquake is given. The motion of the train is modeled in multibody dynamics with nonlinear springs and dampers used to connect components. An efficient mechanical model for contact dynamics between the wheel and rail during an earthquake is presented. The railway structure is modeled with various finite elements. A nonlinear spring element based on a trilinear elastic-plastic material model is given for the concrete railway structure during an earthquake. A substructure model where a train runs repeatedly has been devised to obtain an approximated combined motion of the long train with many cars connected and the railway structure during an earthquake. A modal method has been developed to solve large-scale nonlinear equations of motion of the train and railway structure effectively. Based on the present method, a computer program DIASTARS for the dynamic interaction analysis of a Shinkansen train (high-speed train in Japan) and the railway structure during an earthquake has been developed. Numerical examples are demonstrated.

Computational model of a Shinkansen train running on the railway structure and the industrial applications

Abstract In this paper, an efficient numerical model for the dynamic interaction analysis of a Shinkansen train (bullet train) and railway structure is given. The motion of a Shinkansen train is modeled in multibody dynamics with nonlinear springs and dampers employed. A simple and efficient mechanical model for interaction between wheel and rail is described. The railway structure including the track is modeled with various finite elements. A nonlinear spring element based on a trilinear elastic–plastic material model is devised to express the elastic–plastic behavior of parts in the structure effectively for practical problems. Combined transient dynamic response of the train and railway structure is obtained by solving the nonlinear equations of motion using a modal method. A computer program DIASTARS has been developed for the interaction analysis of a Shinkansen train and the railway structure. The visualization program has been developed to visualize the combined dynamic behavior of the train and railway structure. Applications to industrial problems are demonstrated.

Simulation and visualization of a high-speed Shinkansen train on the railway structure

The equation of the combined motion of a Shinkansen train (bullet train), rail, and the railway structure is described, and an efficient numerical method to solve the combined response is discussed. Mechanical models for the train with as many as 16 vehicles connected and for the interaction between wheel and rail are described. A computer program for the simulation of a Shinkansen train running on the railway structure at high speed has been developed. A visualization program, VIS, for the animation of dynamic motion of the train and railway structure has been developed. Numerical examples are demonstrated.

Exact Time Integration for Dynamic Interaction of High-Speed Train and Railway Structure Including Derailment During an Earthquake

In this paper a robust and efficient computational method to solve for the dynamic interaction of a high-speed train and railway structure including derailment during an earthquake is given. The motion of the train is modeled in multibody dynamics. Mechanical models to express contact-impact behaviors between wheel and rail before derailment and between wheel and the track structure after derailment are described to solve the interaction during an earthquake. The motion of railway structure is modeled with various finite elements. Modal reduction has been developed to solve nonlinear equations of the combined motion of the train and railway structure effectively. A robust time integration using an exact time integration in the modal coordinate has been developed to avoid a round-off error appeared in the numerical time integration for a very small time increment to solve the interaction including derailment during an earthquake. Some examples are demonstrated.

A combined multibody and finite element approach for dynamic interaction analysis of high-speed train and railway structure including post-derailment behavior during an earthquake

A combined multibody and finite element approach is given to solve the dynamic interaction of a Shinkansen train (high-speed train in Japan) and the railway structure including post-derailment during an earthquake effectively. The motion of the train is expressed in multibody dynamics. Efficient mechanical models to express interactions between wheel and track structure including post-derailment are given. Rail and track elements expressed in multibody dynamics and FEM are given to solve contact problems between wheel and long railway components effectively. The motion of a railway structure is modeled with various finite elements and rail and track elements. The computer program has been developed for the dynamic interaction analysis of a Shinkansen train and railway structure including post derailment during an earthquake. Numerical examples are demonstrated.

Development of Silent Steel Railway Bridge Equipped with Floating Ladder Track and Floating Reinforced Concrete Deck

As a countermeasure against structure-borne noise of steel railway bridge, we developed a new type silent steel railway bridge equipped with floating ladder track and floating reinforced concrete deck. As a result of the train running test, it was apparent that the new steel railway bridge with double floating system has reduced vibration velocity level of 10.5dB(A) at the main girder webs as compared with a steel railway bridge which has directly fastened tracks.

Computational Model for a High Speed Train Running on the Railway Structure Including Derailment during an Earthquake

The computational method to solve for the dynamic interaction between a high-speed train and the railway structure including derailment during an earthquake is given. The motion of the train is expressed in multibody dynamics. Efficient mechanical models to express contact-impact behaviors between wheel and the track structure including derailment during an earthquake are given. Rail and track elements with multibody dynamics and FEM combined have been developed. A nonlinear spring element based on a trilinear elastic-plastic material model with the kinematic hardening is given for a concrete railway structure under cyclic loads during an earthquake. The motion of a railway structure is modeled with various finite elements and also with rail and track elements. A modal reduction is applied to solve the problem effectively. An exact time integration scheme has been developed that is free from the round-off error for very small time increments needed to solve the interaction between wheel and railway structure including derailment during an earthquake. Numerical examples are demonstrated.

Identification of Dynamic Properties of Open-Deck Viaducts Under Passing Train Loads

When planning the introduction of high-speed trains on existing viaducts, it is important to grasp the resonance phenomenon by measuring the vibration of actual bridges and understand this phenomenon from the engineering perspective. In this study, the author focused on the open-deck viaducts in snowy cold regions, where high-speed trains will be introduced, carried out vibration monitoring of actual bridges utilizing the passing train loads and identified their dynamic properties with ERA (Eigensystem Realization Algorithm). When identifying dynamic properties, the first bending mode and the first torsional mode were studied, and it was found that the first torsional mode is dominant after a train has passed, while the first bending mode is dominant during the passing of a train. The damping ratio of the first bending mode was 1.5-1.9%, which is slightly lower than the commonly used value 2%. In addition, with the simplified model using the identified dynamic properties, the resonance phenomenon induced by high-speed trains was investigated empirically.

Identification of High-order Local Vibration Properties of RC Viaduct

In order to sustain the development of high-speed trains, it is necessary for railway bridges to grasp the dynamic behavior of bridge members precisely, by identifying not only whole bridge vibration properties but also local ones, and low-order to high-order mode vibration properties. Actually, there are common concerns over resonance and noises caused by the vibration of bridge members due to high-speed trains. However, there have been few vibration measurement experiments for carrying out identification of high-order member vibration properties. In this circumstance, the authors conducted the passing train experiment, measuring vibration concurrently at several points on the intermediate and projecting slabs of a RC viaduct for high-speed trains. Through the vibration measurement experiment, the authors verified the possibility of detection of high-order vibration modes of members and identified the outstanding vibration mode when a high-speed train passes. This paper also includes a few discussions about the relation between vibration properties and the outstanding frequency induced by the multi-axle load of trains. By accumulating the data of actual measurements of local vibration, it would be possible to contribute to the sophistication of finite element analysis, etc.

An Efficient Numerical Method for Dynamic Interaction Analysis of Shinkansen Train and Railway Structure During an Earthquake

In this paper, a simple and efficient numerical method to solve for the dynamic interaction of a Shinkansen train (high-speed train in Japan) and railway structure during an earthquake is given. The motion of the train is modeled in multibody dynamics with nonlinear springs and dampers used to connect components. An efficient mechanical model for contact dynamics between wheel and rail during an earthquake is presented. The railway structure is modeled with various finite elements. A three-dimensional nonlinear spring element based on a trilinear elastic-plastic material model is given for the concrete railway structure during an earthquake. A loop structure model has been devised to obtain an approximated combined motion of the train and railway structure during an earthquake. A modal method has been developed to solve large-scale nonlinear equations of motion of the train and railway structure effectively. Based on the present method, a computer program DIASTARS for the dynamic interaction of a Shinkansen train and railway structure during an earthquake has been developed. Numerical examples are demonstrated.Copyright