Wu Yaping

Temperature Rising by a High-Speed Train Running through a Long Tunnel

A significant amount of thermal energy is given off in the tunnel when a high-speed train is running through a long tunnel, and only few of thermal energy generated from this case shall be brought out of the tunnel by the train. The thermal energy is the result of dissipation caused by aerodynamic drag, mechanical resistances, and inefficiencies in the power unit. In this paper, heating of aerodynamic drag are calculated in terms of pressure drag and friction resistance as well. Heating of auxiliary equipment, train equipment, train braking and pantograph electric arc etc. has also been comprehensively considered, and the energy loss of heat conduction induced by tunnel wall has been taken into account. As a result, the temperature rising in the long tunnel is generated and the result can provide us with a useful reference for design of the long tunnel for the high-speed train and its traction capacity.

Multifield coupling model and its applications for pile foundation in permafrost

Importing the interface element which links the frozen soil base with concrete piles and considering the couplings of stress field, temperature field and moisture field, this paper es- tablishes the nonlinear visco-elastic plastic finite element model of pile-soil. For a practical bridge structure the stress field and displacement field of single pile in freezing process are calculated. This paper emphatically studies the process of the tangential frost heave stress field, freezing stress field and displacement field varying with time, and ulteriorly studies time variation process of single pile carrying capacity in freezing process.

The Study of Temperature Filed by High-Speed Train Traveling through a Long Tunnel

Aerodynamic effect induced by high-speed train moving in very long tunnel is significantly different from short tunnel. In this paper a simulation of high-speed train traveling through a deep buried long tunnel has been made. According to train and tunnel system, Navier-Stokes equation of three-dimensional flow is solved by finite volume method. An unsteady, compressible, turbulent calculation was carried out using a RNG k¿εturbulence model employing a second-order upwind discretization scheme. Based on the same blocking ratio and head shape, various speed conditions, pressure drag between train nose and train tail, friction drag on train body and the quantity of heat produced by the energy-consuming for working of train against all resistance are evaluated. The heating of train drag, train wall friction, auxiliary equipment, train equipment, train braking and pantograph electric arc etc. has also been comprehensively considered, and the energy loss of heat conduction introduced by tunnel wall has been taken into account. The temperature rising and variation with time in the tunnel is predicted.

Nonlinear Computation of Shear Lag Effect of Box Beam

This paper presents an initial value solution of static equilibrium differential equations of thin-walled box beams considering shear lag, shear deformation and geometric nonlinear, which was used to establish the related element stiffness matrix, geometric stiffness matrix and equivalent nodal forces vector. So that the nonlinear analysis of thin-walled box beams is admitted into the program system of matrix-displacement method. The nonlinear equilibrium equation of thin-walled box beam element in the Lagrangian coordinates and its iteration expression were established, and in the computation the displacement-based convergence criterion was used to solve the problem.

Finite Element Analysis of Stability of Continuous Welded Rail with Minor Radius Curve

This paper establishes the finite element model of continuous welded rail with the minor radius curve and infers the corresponding value formula. Using this finite element model, this paper analyzes the influence of dynamic and static load on the stability of continuous welded rail with the minor radius curve, which indicates that the model can be used to simulate more accurately the actual situation of the track lateral displacement due to the ambient temperature changing and dynamic load (unbalanced centrifugal force and vertical vibration force caused by track irregularity) effect.