Análise dinâmica não linear de problemas envolvendo massas móveis aplicadas em cabos e elementos de viga

Abstract

This dissertation deals with the nonlinear dynamic analysis of moving masses applied on cables and beam elements. This mechanical system is often used in systems for transport of passenger, such as trains, and also enables the use of autonomous systems used for inspectionand maintenance of cable structures. The structural systems are modeled numerically with the aid of a formulation based on the Finite Element Method. There are recent articles that work these analyzes using various solutions methods, but all show a high level of difficulty at thetime of discretization of the governing equations and the implementation of the algorithms. Such methods, using the basic concept of the Finite Element Method of the local and global coordinate systems, are forced to work with a larger number of terms in the governing equations. Thus, it becomes necessary the development of simple methods with morenumerical accuracy, for the dynamic nonlinear formulation. Therefore, the main objective of this work is to present a numerical approach of the system mass-cable and mass-beam using the concept of positional geometrical nonlinearity. Using this methodology, the analysis willbe presented to moving masses traveling with constant or variable velocities in dimensionless or real physical problems. For these problems, sets of results will be presented for the mechanical behavior analyses, as the midspan vibration during the course of the mass alongthe structural system (forced vibrations) and after the mass finishing their entire course (free vibrations). Preliminary results point to the increase of stiffness of the system mass-cable during the course of the mass, with the increase of mass velocity. This phenomenon is notobserved in beam-mass system.