Papers by Author: Hua Song

Abstract: Abstract：Based on the real geometry and boundary conditions of the wheels and rails, the models of 60kg/m U75V heavy rail and the wear regions of LM are built using ANSYS/LS-DYNA software. The internal stress value and variation of the heavy rails that were repeatedly crushed by the rolling wheels are analyzed using the ANSYS/LS-DYNA3D software. The relationship of the internal stress and variation of heavy rails with the repeated rolling of the wheels are obtained. It provides an important theoretical proof and reference significance to prevent the different failure behaviors of the rails.

Abstract: The hot preflex cooling and compound straightening are the last two consecutive deformation processes and determine the straightness, residual stress and cross-sectional size for fabricating hundred-meter heavy rail products. The compound straightening process needs to be adjusted by the preflex cooling status. For studying the straightness, residual stress and cross-sectional size of heavy rail products, the preflex cooling model (including the residual stress) of heavy rail after cooling should be taken as straightening model for studying the compound straightening. In this paper, the results by ANSYS implicit analysis (geometry model and stress state of the cold heavy rail) is fully imported to the compound straightening by ANSYS/LS-DYNA explicit analysis through an implicit-explicit conversion method, which resolved the connection problem of coupling and analysis models for solving complex models in multi-physical fields. It is very significant for solving the similar problems in engineering.

Abstract: Uneven distribution of temperature is one of the important factors which influences heavy rail bending changes during the cooling process. Through the research of temperature field can reasonable analysis the heavy rail bending change rule, so it is necessary to study the temperature change rule during heavy rail cooling process. This paper adopts finite element analysis software ANSYS to set up three-dimensional models of U75V heavy rail and the cooling bed, and numerical simulate the cooling process. In which, it is studied the temperature changing rules and its distribution rules, emphatically analyzed temperature changing rule during the phase transition phase, and got the temperature changing rules and distribution rules in final cooling time. Especially, it is considered that the heavy rail placed on its side, the latent heat of phase transition and thermal radiation. This research can provide the theory basis and the advisory opinion on the formulation of cooling technological parameters and preflex regulations of the rail.

Abstract: In this article, the Pro/Engineer virtual prototyping technology is used for three dimensional entity modeling, assembly, and simulation analysis of 1000KN·m large backstop in four design plans to confirm the integrity and assembling of backstop. By using the ANSYS/LS-DYNA software, it makes numerical simulation analysis of the backstop in non-return process, and through the analysis comparison to the simulation result, it obtains the optimization design plan of the 1000KN·m backstop.

Abstract: The cooling process of heavy rail is the important step to the output, that the preflexed rail is cooled on the stepping-type cold bed which has been carried by the chain transmission device. We employed the finite element method to analyze the bending deformation of the U75V rail through natural cooling process, the effected factors including the rail side-laying on the cold bed, the latent heat of phase change, and the thermal radiation are considered in the analysis. In the paper, we discussed the establishment of the heavy rail cooling model, the cooling parameters and the boundary condition, and emphatically analyzed the rail bending deformation changes and its principles through the cooling process. The study of the hundred-meter high speed heavy rail can provide the theoretical foundation and reference value to the formulation of cooling technical parameters and preflex technical schedule.

Abstract: When rolled heavy rail is on the cooling bed for natural cooling, the heat transfer coefficient has important effect on the bending and section sizes of cooled heavy rail. In the paper, the heat-stress couple module of ANSYS software is adopted to carry on numerical simulation on the cooling process of 60kg/m U75V heavy rail, and we obtain the change rule that heat transfer coefficient has effect on bending curvature and section sizes of cooled heavy rail. This study is of great reference value on cooling bed design and the formulation of cooling technological parameters for high speed heavy rail.

Abstract: This paper adopted explicit dynamics FEM software ANSYS/LS-DYNA and carried out the numerical simulation calculation of 9 roller horizontal straightening and 8 roller vertical straightening for 60 kg/m heavy rail with original curvature. The reductions of straightening rollers are taken as the main effective factor to the residual stress in the straightening regulation. It adopted orthogonal experimental method to obtain the main effective factors for straightness and residual stress. In the assurance of meeting the straightness, it obtained the regulation in which the residual stress is the smallest, so it makes the important theoretical and actual sense to formulate the rational straightening process and improve the straightening quality of rail.

Abstract: It has established the FEM model of nine horizontal roller straightening with original curvature for 60㎏/m heavy rail by using explicit dynamics software ANSYS/LS-DYNA in the paper, and it carried out the dynamic simulation process of the nine horizontal roller straightening, analyzed the stress changing rules of heavy rail in the seven deformation zones during the straightening process , even studied the value and distributive condition of residual stress after straightening, disclosed the mechanism of the residual stress in the heavy rail straightening process, and the paper is a guidance to improve heavy rail quality in straightening craft. It has the reference value to the design of heavy rail straightening machine and the formulation of the straightening regulations.

Abstract: Electric contact is an important component of high voltage circuit breaker switch lubicle, isolating switch and ground switch. It is composed of arc-extinction end and conduction end. The usual material of arc-extinction end is copper-tungsten and the usual material of conduction end is copper or chrome-copper. Currently, four process for making the integral electric contact such as common brazing, vacuum brazing, electric-beam welding; liquid-phase sintering is of the best integral technique capability. This article puts forward a process by friction welding for integral Cu-W electric contact, and studies about the weldability between copper-tungsten and copper or chrome-copper, and between copper and chrome-copper. In order to solve the worse weldability between copper-tungsten and copper or chrome-copper, the design conception of intermediate layer is tentatively suggested. From experimental results, using the production method of friction welding is practicable to integral electric contact. It has some advantages, such as high availability of material, high productivity, high ratio of finish products, and it has no any influence on environment.