Study On Deformation And Mechanical Characteristics Of High-Speed Maglev Composite Guideway

With the development of maglev transportation, we may confront numerous complex terrain and geology situations during the construction of middle-long-distance maglev lines. Accordingly, these lines are certain to run across many long-distance obstacles. Presently, there doesn't exist long-span guideway home and abroad suitable for the running of maglev train, so there appears the structural style for maglev composite guideway. In this style of structure, the guideways with highly precise function surfaces are erected over the normal bridge in order to stride across the obstacles mentioned above. However, some related findings in this respect have not been reported to the public. Therefore, as an indispensable part of maglev line, this kind of structure deserves our efforts to do deep and systematical research.The author carries out a further study on maglev composite guideway in this thesis from the perspective of Statics and Dynamics. Based on the maglev codes, the author explores the following issues respectively by referring to the present findings with regard to maglev guideway and railway bridge, e.g. the research methods for maglev composite guideway, the indexes and limits for deformation-controlling, the factors influencing deformation, the influence way, the proper ranges of main structure parameters for structure-designing, the dynamic design requirements for maglev composite guideway and so on. The achievements of the present study in this thesis may provide theoretic foundation and reference for parameter choice and scheme selection of composite guideway. The main research is as follows:(1) Exploring a series of indexes and corresponding limits formula, which are used to control the deformation of maglev composite guideway. The author in this thesis conducts a comparative study of maglev composite guideway and normal guideway on structural style and deformation behavior etc. Furthermore, based on the previous achievements with regard to maglev guideway and railway bridge, the author carries out a detailed study on a series of indexes and corresponding limits formula, which are used to control the deformation of maglev composite guideway.(2) Conducting an alternative study on suitable structural style of maglev composite guideway. The author in this part surveys the composite guideway of upper track, stiffness of understructure, as well as the linked mode by analyzing and comparing the bridge criteria home and abroad on allowable values of vertical and lateral stiffness of bridge (or guideway), coupled with the structure and stress characteristics of maglev composite guideway. According to the study conducted above, the author tries to design the scheme for the three-span continuous composite guideway bridges with an 80-meter main span, and then establish the finite element analysis model.(3) Analyzing the deformation of composite guideway under the influence of such loads as ambient temperature and maglev train. Through a comparative study on the bridge norms home and abroad about temperature gradient mode, the author in the third part attempts to explore the temperature gradient modes of different parts in maglev composite guideway. Based on the study of composite guideway deformation features and the factors under the influence of ambient temperature and maglev train etc, the author gets the result of influential way exerted by roof width, span ratio, vertical stiffness, and linked mode between upper track and understructure on the deformation of composite guideway and puts forward the proper ranges of main structure parameters for maglev composite guideway and also improves the limits formula of deformation-controlling index.(4) Studying the dynamic characteristics of maglev composite guideway structure. Through the application of theories from Structure Dynamics, Vehicle Dynamics and Electromagnetic Control, as well as the techniques of modal analysis, the author sets up the model for the dynamic analysis on maglev train-composite guideway of magnetic force based on active control system, and then writes a program on train-composite guideway dynamic analysis. By means of the simulation program compiled in this dissertation, the author analyses and calculates the whole process of high-speed maglev train passing on the composite guideway and also studies the effects of different maglev train speed, marshalling, span ratio, vertical stiffness and damping on train and composite guideway responses. The relationship between primary frequency of composite guideway and its corresponding dynamic responses is also analyzed in this part. At last, the author puts forward the design requirements of maglev composite guideway. 115 figures, 47 tables, 139 references.