Study On The Frictional Factor In Collision Problem

The frictional factor in collision problem is a highly nonlinear problem with variable boundary, the traditional solution method is used an accurate rigid body model based on the Newton recovery coefficient to simplify the collision process in order to reduce the solving difficulty. Nowadays, owning to the traditional analytical method is too difficult to complete the whole collision solving in dynamic response, the current mainstream methods of researching the collision problem is focusing on the numerical methods such as the finite segment method, the finite element method and the dynamic substructure method.This thesis is based on the finite element model, and an oblique collision problem of the two-dimensional beam with friction is studied. The numerical recurrent expression for the collision between an oblique beam and a simply supported beam is presented based on the theory of two-dimensional dynamic contact. An oblique collision calculation program of 2D beam is programmed using Fortran. The different angle affects to the beam-beam collision is discussed, an empirical formula of the frictional coefficient, which was presented by Bochet, is accepted to improve the friction in the tangential contact model. Comparing the results between using the Coulomb friction theory and the improved collision contact theory, it is shown that there are slight differences to the collision influence between the two methods. Furthermore,Adopting Coulomb’s friction models, the value of vertical displacement will be affected by the tangential friction. As the initial angle increases, the magnitude of the vertical displacement will also be increased. The dynamic response of the beam indicates that owning to the existence of tangential friction, the collision objects will be signally affected in plane motion, and will be leaded to a slight reverse slip and a stick-and-slip phenomenon.Combining the advantages of the visualization interface in VB language and the high efficient computing capability in Fortran language, author has participated in the development of the software named Structural Dynamic Response Analysis(simply as SDRA), and the functions of the software in pre-processing and post-processing has been added. In terms of pre-processing, the shortcoming of the traditional manual input data is overcome, a series of functions is realized such as the automatic division of the plane quadrilateral mesh, automatic numbering, and the automatic input data. In the post-processing interface, the dynamic responses of the beam oblige collision results can be shown by the software. Besides, the node’s displacements, velocity, impact force in the beam can be drawn using the software, it is suitable for fast dynamic response of the numerical analysis of the bridge structure.