Uma formulação consistente para análise não-linear de estruturas de cabos suspensos

Abstract

A general theory for the analysis of the non-linear behaviour of suspension cables structures by the finite element method is presented. The formulation takes into account the material and geometric nonlinearities. The theory is developed applying a Lagrangian formulation where the corotacional technique is used to obtain the tangent stiffness matrix of the space cable element. The formulation intends to be as general as possible, allowing for the nodes to undergo large displacements and the elements to undertake large strains. Besides, elasto-plastic material can be used. A static incremental analysis will be perfomed, applying an incremental, monotonic and increasing load, proportional or not, until partial or global failure of the cable structure occurs. The solution of the problem requires an incremental-iterative procedure, such as the Newton-Raphson Method, to insure the convergence. An easy-to-use computer program was developed which allows for analyses of suspension cables takingencompassing large displacements effects and the inelastic behaviour of the cables. The computational coding of the element was performed using the PASCAL programming language obeying the DELPHI 4.0 standards. The examples presented were compared with theoretical results and with results produced by some commercial programs, showing the correctness and accuracy of the developed program.