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

2007 ◽  
Author(s):  
M. Tanabe ◽  
N. Matsumoto ◽  
H. Wakui ◽  
M. Sogabe ◽  
H. Okuda ◽  
...  
Keyword(s):  
Numerical Method ◽  
High Speed ◽  
Large Scale ◽  
Interaction Analysis ◽  
Plastic Material ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Material Model ◽  
Dynamic Interaction ◽  
Contact Dynamics

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.

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

2008 ◽  
Vol 3 (4) ◽  
Author(s):  
M. Tanabe ◽  
N. Matsumoto ◽  
H. Wakui ◽  
M. Sogabe ◽  
H. Okuda ◽  
...  
Keyword(s):  
Numerical Method ◽  
High Speed ◽  
Large Scale ◽  
Interaction Analysis ◽  
Plastic Material ◽  
Equations Of Motion ◽  
Material Model ◽  
Dynamic Interaction ◽  
Contact Dynamics ◽  
High Speed Train

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.

An Efficient Numerical Method for Dynamic Interaction Analysis of High-Speed Shinkansen Vehicles, Rail, and Bridge

1994 ◽  
Author(s):  
Makoto Tanabe ◽  
Hajime Wakui ◽  
Nobuyuki Matsumoto
Keyword(s):  
Finite Element ◽  
Numerical Method ◽  
High Speed ◽  
Interaction Analysis ◽  
Equations Of Motion ◽  
Time Integration ◽  
Integration Scheme ◽  
Element Formulation ◽  
Exact Time ◽  
Time Integration Scheme

Abstract This paper describes a finite element formulation to solve for the combined dynamic behavior of Shinkansen (bullet train) vehicles, irregular rails, and bridges. A mechanical model for interactions between a wheel and an irregular rail is discussed. The bridge is modeled by use of various finite elements. An efficient numerical method, based on modal analysis and exact time integration, is described for solving the nonlinear equations of motion of the Shinkansen vehicle and bridge. The convergence of the exact time integration scheme is discussed and compared with a previous numerical time integration scheme. A finite element computer program has been developed to analyze the dynamic response of Shinkansen vehicles operating at high speed over irregular rails and a bridge. Numerical examples are presented to demonstrate the effectiveness and validity of the present approach.

scholarly journals Prevention of Mountain Disasters and Maintenance of Residential Area through Real-Time Terrain Rendering

2021 ◽  
Vol 13 (5) ◽  
pp. 2950
Author(s):  
Su-Kyung Sung ◽  
Eun-Seok Lee ◽  
Byeong-Seok Shin
Keyword(s):  
Real Time ◽  
Graphics Processing Units ◽  
High Speed ◽  
Large Scale ◽  
Civil Engineering ◽  
Three Dimensional ◽  
Sampled Data ◽  
Residential Areas ◽  
Terrain Rendering ◽  
Mountain Disasters

Climate change increases the frequency of localized heavy rains and typhoons. As a result, mountain disasters, such as landslides and earthworks, continue to occur, causing damage to roads and residential areas downstream. Moreover, large-scale civil engineering works, including dam construction, cause rapid changes in the terrain, which harm the stability of residential areas. Disasters, such as landslides and earthenware, occur extensively, and there are limitations in the field of investigation; thus, there are many studies being conducted to model terrain geometrically and to observe changes in terrain according to external factors. However, conventional topography methods are expressed in a way that can only be interpreted by people with specialized knowledge. Therefore, there is a lack of consideration for three-dimensional visualization that helps non-experts understand. We need a way to express changes in terrain in real time and to make it intuitive for non-experts to understand. In conventional height-based terrain modeling and simulation, there is a problem in which some of the sampled data are irregularly distorted and do not show the exact terrain shape. The proposed method utilizes a hierarchical vertex cohesion map to correct inaccurately modeled terrain caused by uniform height sampling, and to compensate for geometric errors using Hausdorff distances, while not considering only the elevation difference of the terrain. The mesh reconstruction, which triangulates the three-vertex placed at each location and makes it the smallest unit of 3D model data, can be done at high speed on graphics processing units (GPUs). Our experiments confirm that it is possible to express changes in terrain accurately and quickly compared with existing methods. These functions can improve the sustainability of residential spaces by predicting the damage caused by mountainous disasters or civil engineering works around the city and make it easy for non-experts to understand.

Stresses in Ultrasonically Assisted Turning

2006 ◽  
Vol 5-6 ◽  
pp. 351-358 ◽  
Author(s):  
N. Ahmed ◽  
A.V. Mitrofanov ◽  
Vladimir I. Babitsky ◽  
Vadim V. Silberschmidt
Keyword(s):  
Ultrasonic Vibration ◽  
Vibration Frequency ◽  
Cutting Forces ◽  
Plastic Material ◽  
Process Zone ◽  
Three Dimensional ◽  
Rate Sensitivity ◽  
High Strength ◽  
Material Model ◽  
Shear Stresses

Ultrasonically assisted turning (UAT) is a novel material-processing technology, where high frequency vibration (frequency f ≈ 20kHz, amplitude a ≈15μm) is superimposed on the movement of the cutting tool. Advantages of UAT have been demonstrated for a broad spectrum of applications. Compared to conventional turning (CT), this technique allows significant improvements in processing intractable materials, such as high-strength aerospace alloys, composites and ceramics. Superimposed ultrasonic vibration yields a noticeable decrease in cutting forces, as well as a superior surface finish. A vibro-impact interaction between the tool and workpiece in UAT in the process of continuous chip formation leads to a dynamically changing stress distribution in the process zone as compared to the quasistatic one in CT. The paper presents a three-dimensional, fully thermomechanically coupled computational model of UAT incorporating a non-linear elasto-plastic material model with strain-rate sensitivity and contact interaction with friction at the chip–tool interface. 3D stress distributions in the cutting region are analysed for a representative cycle of ultrasonic vibration. The dependence of various process parameters, such as shear stresses and cutting forces on vibration frequency and amplitude is also studied.

Three-dimensional instantaneous structure of a shock wave/turbulent boundary layer interaction

2009 ◽  
Vol 622 ◽  
pp. 33-62 ◽  
Author(s):  
R. A. HUMBLE ◽  
G. E. ELSINGA ◽  
F. SCARANO ◽  
B. W. van OUDHEUSDEN
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Turbulent Boundary Layer ◽  
High Speed ◽  
Large Scale ◽  
Three Dimensional ◽  
Reflected Shock Wave ◽  
Layer Interaction ◽  
Reflected Shock ◽  
Boundary Layer Interaction

An experimental study is carried out to investigate the three-dimensional instantaneous structure of an incident shock wave/turbulent boundary layer interaction at Mach 2.1 using tomographic particle image velocimetry. Large-scale coherent motions within the incoming boundary layer are observed, in the form of three-dimensional streamwise-elongated regions of relatively low- and high-speed fluid, similar to what has been reported in other supersonic boundary layers. Three-dimensional vortical structures are found to be associated with the low-speed regions, in a way that can be explained by the hairpin packet model. The instantaneous reflected shock wave pattern is observed to conform to the low- and high-speed regions as they enter the interaction, and its organization may be qualitatively decomposed into streamwise translation and spanwise rippling patterns, in agreement with what has been observed in direct numerical simulations. The results are used to construct a conceptual model of the three-dimensional unsteady flow organization of the interaction.

A Three-Dimensional Pedestrian–Structure Interaction Model for General Applications

2018 ◽  
Vol 18 (09) ◽  
pp. 1850107 ◽  
Author(s):  
Yan-An Gao ◽  
Qing-Shan Yang ◽  
Yun Dong
Keyword(s):  
Large Scale ◽  
Damping Ratio ◽  
Three Dimensional ◽  
Interaction Model ◽  
Dynamic Interaction ◽  
Structure Interaction ◽  
Numerical Studies ◽  
Structure Dynamic ◽  
Proposed Model ◽  
Reaction Forces

A three-dimensional (3D) pedestrian–structure interaction (PSI) system based on the biomechanical bipedal model is presented for general applications. The pedestrian is modeled by a bipedal mobile system with one lump mass and two compliant legs, which comprise damping and spring elements. The continuous gaits of the pedestrian are maintained by a self-driven walking kinetic energy, which is a new driven mechanism for the mobile unit. This self-driven mechanism enables the pedestrian to operate at a varying total energy level, as an important component for further modeling of the crowd-structure dynamic interaction. Numerical studies show that the pedestrian walking on the structure leads to a reduction in the natural frequency, but an increase in the damping ratio of the structure. This model can also reproduce the reaction forces between the feet and structure, similar to those measured in the field. In addition, the proposed model can well describe the 3D pedestrian–structure dynamic interaction. It is recommended for use in further study of more complicated scenarios such as the dynamic interaction between a large scale kinetic crowd and slender footbridge.

Dynamic Interaction Analysis of Maglev-Guideway System Based on a 3D Full Vehicle Model

2017 ◽  
Vol 17 (01) ◽  
pp. 1750006 ◽  
Author(s):  
Dong-Ju Min ◽  
Myung-Rag Jung ◽  
Moon-Young Kim ◽  
Jong-Won Kwark
Keyword(s):  
Dynamic Equilibrium ◽  
Interaction Analysis ◽  
Equations Of Motion ◽  
Dynamic Interaction ◽  
Surface Irregularity ◽  
Superposition Method ◽  
Vehicle Model ◽  
Equilibrium Equations ◽  
Coupled Equations ◽  
Maglev Vehicle

The purpose of this paper is to develop a detailed 3D maglev vehicle and guideway model and investigate the dynamic response characteristics of the coupled system. For this, the maglev vehicle is modeled as one cabin and four bogies having eight electromagnetics, four sensors, and four secondary suspensions based on the Urban Transit Maglev (UTM) system in Korea. The 3D dynamic equilibrium equations of the cabin and bogies are derived by considering the actively controlled electromagnetic forces. Also, the equations of motion for the guideway are derived using the modal superposition method for vertical, lateral, and torsional modes. The resulting coupled equations of motion are then solved using a predictor–corrector iterative algorithm. Finally, through the numerical simulation of the developed system, the responses using the 3D maglev vehicle model are compared with those obtained by the corresponding 2D model. The effects of surface irregularity on the dynamic interaction behaviors are then evaluated for increasing vehicle speeds. Particularly, the 3D resonance conditions of the guideway girder and the maglev vehicle are presented considering the resonance conditions due to equidistant moving loads. In addition, some resonance phenomena are rigorously explored, including the lateral resonance by a series of vehicles running on a girder.

scholarly journals A platform for brain-wide imaging and reconstruction of individual neurons

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Michael N Economo ◽  
Nathan G Clack ◽  
Luke D Lavis ◽  
Charles R Gerfen ◽  
Karel Svoboda ◽  
...  
Keyword(s):  
Long Range ◽  
High Speed ◽  
Large Scale ◽  
Three Dimensional ◽  
Image Data ◽  
Mammalian Brain ◽  
Projection Neurons ◽  
Computational Tools ◽  
Two Photon ◽  
Axonal Arbors

The structure of axonal arbors controls how signals from individual neurons are routed within the mammalian brain. However, the arbors of very few long-range projection neurons have been reconstructed in their entirety, as axons with diameters as small as 100 nm arborize in target regions dispersed over many millimeters of tissue. We introduce a platform for high-resolution, three-dimensional fluorescence imaging of complete tissue volumes that enables the visualization and reconstruction of long-range axonal arbors. This platform relies on a high-speed two-photon microscope integrated with a tissue vibratome and a suite of computational tools for large-scale image data. We demonstrate the power of this approach by reconstructing the axonal arbors of multiple neurons in the motor cortex across a single mouse brain.

scholarly journals Visualization of Large-scale Atomic Interactions During the Melting and Crystallization Process

VLSI Design ◽  
2001 ◽  
Vol 13 (1-4) ◽  
pp. 269-271
Author(s):  
Roman Durikovic
Keyword(s):  
Large Scale ◽  
Defect Formation ◽  
Equations Of Motion ◽  
Material Model ◽  
Atomic Scale ◽  
Three Dimensions ◽  
Langevin Equations ◽  
Short Range Repulsion ◽  
Solid Liquid Interface ◽  
Behaviour Simulation

Atomic-scale material model capable of melting, crystallization and amorphization has been developed to examine the defect formation and crystal growth processes from melted silicon (Si) based on the ordinary Langevin equations of motion. The developed computer system consists of simulation and visualization part. Simulation supports the large-scale molecular-dynamics (MD) clusters with solid/liquid interface responding interactively to the control parameters such as the temperature gradient and pulling speed. Material behaviour simulation is limited to 104 particle objects representing different atoms. A particle in proposed dynamic system interacts through attractive covalent forces and short-range repulsion forces in all three dimensions. This research was conducted to understand the processes that can control the quality of single-crystal Si grown from the melt by Czochralski crystal puller.

Modal Analysis of Ballooning Strings With Small Sag

1999 ◽  
Author(s):  
Rongjun Fan ◽  
Sushil K. Singh ◽  
Christopher D. Rahn
Keyword(s):  
Steady State ◽  
High Speed ◽  
Natural Frequencies ◽  
Rotation Speed ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Mode Shapes ◽  
Theoretical Predictions ◽  
Nonlinear Equations Of Motion

Abstract During the manufacture and transport of textile products, yarns are rotated at high speed and form balloons. The dynamic response of the balloon to varying rotation speed, boundary excitation, and disturbance forces governs the quality of the associated process. Resonance, in particular, can cause large tension variations that reduce product quality and may cause yarn breakage. In this paper, the natural frequencies and mode shapes of a single loop balloon are calculated to predict resonance. The three dimensional nonlinear equations of motion are simplified via small steady state displacement (sag) and vibration assumptions. Axial vibration is assumed to propagate instantaneously or in a quasistatic manner. Galerkin’s method is used to calculate the mode shapes and natural frequencies of the linearized equations. Experimental measurements of the steady state balloon shape and the first two natural frequencies and mode shapes are compared with theoretical predictions.

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