A FEM Formulation For Vehicle-Bridge DynamicInteraction Problems

• Main Authors: Yang,Chia-Ying, 楊佳螢
• Other Authors: Lee,Yang-Jye
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/22273236142977552469

碩士 === 國立宜蘭大學 === 土木工程學系碩士班 === 99 === In this article, we are aiming at a study on a typical vehicle-bridge dynamic interaction problem in which uneven road surface profile can be considered. The objective is a time-domain FEM analysis procedure for the numerical calculations of the dynamic responses of a vehicle-bridge system while the vehicle is moving along the surface of this bridge. The FEM formulation can be divided into 5 stages: (1) By using standard FEM procedure, the matrix equations of motions are constructed for both of the vehicle and bridge systems, in which the dynamic interaction forces are temporary unknown quantities. (2) By using the modal shapes of the bridge system, a modal-reduction procedure is performed on the equations of motions of the bridge system. (3) By using the compatibility equations of the displacements at contact points between the vehicle and the bridge, the unknown interaction forces are eliminated to obtain coupled equations of motions for the vehicle-bridge system. (4) By using the modal shapes for the whole vehicle system, further modal-reduction procedure is performed on coupled equations of motions of the whole system. (5) Runge-Kutta numerical scheme is used for the time-stepping solution of the coupled equations of motions which are constructed in the stage (4). In order to validate the numerical procedure proposed, several simplified cases, analytical solutions of which can be obtained, are studied. The numerical results obtained seem to be quite satisfactory as being compared with analytical solutions. Further more, two cases which are studied by previous research are analyzed by using the numerical procedure proposed, numerical results obtained are quite satisfactory as being compared with results obtained by previous research. In order to be a testing of the performance of proposed method in realistic situations, dynamic responses of a 3-span railway bridge induced by a MRT train-set are investigated.