Dynamics of structures

Vertical dynamic response of non-uniform motion of high-speed rails

New semi-analytical solution for a uniformly moving mass on a beam on a two-parameter visco-elastic foundation

In this paper, a two-dimensional numerical model is developed to investigate the effect of rail pad stiffness on the wheel/rail force in a slab track with harmonic irregularity. The model consists ...

Effect of rail pad stiffness on the wheel/rail force intensity in a railway slab track with short-wave irregularity:

Presented herein is a novel computational approach using the moving element method (MEM) for simulating the dynamic response of Mindlin plate resting on a viscoelastic foundation and subjected to m...

Static and Dynamic Analyses of Mindlin Plates Resting on Viscoelastic Foundation by Using Moving Element Method

In this paper, a computational study using the moving element method (MEM) was carried out to investigate the dynamic response of a high-speed train–track system. Results obtained using Hertz contact model and linearized Hertz contact model are compared and discussed. The dynamic responses of a train travelling across a uniform foundation and a transition region are also investigated. Parametric study is performed to understand the effect of various factors on the occurrence and patterns of the jumping wheel phenomenon such as the variation of foundation stiffness, travelling speed of the train and the severity of railhead roughness.

Analysis of high-speed rail accounting for jumping wheel phenomenon

The dynamic response of high-speed train subject to braking is investigated using the moving element method. Possible sliding of wheels over the rails is accounted for. The train is modelled as a 15-DOF system comprising of a car body, two bogies and four wheels interconnected by spring-damping units. The rail is modelled as a Euler–Bernoulli beam resting on a two-parameter elastic damped foundation. The interaction between the moving train and track-foundation is accounted for through the normal and tangential wheel–rail contact forces. The effects of braking torque, wheel–rail contact condition, initial train speed and severity of railhead roughness on the dynamic response of the high-speed train are investigated. For a given initial train speed and track irregularity, the study revealed that there is an optimal braking torque that would result in the smallest braking distance with no occurrence of wheel sliding, representing a good compromise between train instability and safety.

High-Speed Trains Subject to Abrupt Braking

The dynamic response of a high-speed multiple-railcar train experiencing deceleration under braking condition over a straight track is investigated using the moving element method. Possible sliding of train wheels over the rails is accounted for. The train is assumed to comprise a locomotive as the leading railcar and several passenger railcars connected to each other through train couplers. Each railcar is modeled as a 15-DOF system of interconnected car body, two bogies and four wheels. The rail is modeled as an Euler–Bernoulli beam resting on a two-parameter elastic damped foundation. The train and rails are coupled through normal and tangential wheel–rail contact forces. The effects of various parameters, such as braking torque, coupler stiffness, coupler gap, wheel load, wheel–rail contact condition, initial train speed and partial failure in braking mechanism on the dynamic response of the train subject to braking are investigated. It is found that there is significant interaction between neighboring railcars when the braking torque is applied between the optimal and critical torques. The former is the torque that would result in the smallest braking distance with no occurrence of wheel sliding and the latter is the smallest torque to cause wheel sliding in all four wheels.

Multiple-Railcar High-Speed Train Subject to Braking

The dynamic response of a high-speed rail experiencing heavy braking is investigated using the moving element method. Possible sliding of train wheels over the rails as the train decelerates is accounted for. The train is modelled as a 14-DOF system comprising a car body, bogies and wheel sets interconnected by spring-damping units. The railway track is modelled as an infinite Euler–Bernoulli beam resting on a two-parameter elastic-damped foundation. A convected coordinate system attached to the moving train is employed in the formulation of the governing equations. The effects of braking torque, coefficient of static friction between wheels and rail, initial train speed and the severity of railhead roughness (track irregularity) on the dynamic response of the high-speed rail, including the occurrence of the ‘jumping wheel’ phenomenon, are examined. The phenomenon describes the momentary loss of contact between the wheel and track. A combination of high braking torque, large static friction coefficient, h...

Minh Thi Tran

Papers

Vertical dynamic response of non-uniform motion of high-speed rails

Analysis of high-speed rail accounting for jumping wheel phenomenon

High-Speed Trains Subject to Abrupt Braking

Multiple-Railcar High-Speed Train Subject to Braking

Dynamic response of high-speed rails due to heavy braking: