Desenvolvimento de um pré-processador para análise de estabilidade de perfis estruturais de paredes finas

Abstract

Thin-walled profiles have several applications in engineering works. Depending on their function they can be produced in different ways and composed of varied materials. Steel profiles can be used as structural elements due to their high strength. When subjected to efforts of centered compression or bending, they may present stability problems, due to the phenomenon of buckling. Buckling occurs in two predominant forms: global, when there is deformation of the bar as a whole, and local, when there is deformation of the plates that make up the profile. In order to determine the critical buckling load of any bar, it is necessary to use stability analysis programs, such as the General Beam Theory at the University of Lisbon (GBTUL) and the Constrained and Unconstrained and Finite Strip Method (CUFSM). An alternative to these methods is the Isogeometric Analysis (IGA), which uses in its formulation the same functions used in CAD systems, Non Uniform Rational B-Splines (NURBS). NURBS are used for the construction of two-dimensional and three- dimensional models, being applied in the automotive and entertainment industries. The generated models can be refined using the knot insertion and degree elevation algorithms, improving the numerical solution. In this work, it was developed a graphical interface capable of generating models ready for the program of numerical analysis, being possible to choose interactively the geometry, the material, the boundary conditions, the applied load and the type of analysis. The model is then refined according to the user's need and the input file of the analysis program is generated. Several examples of steel profiles subjected to axial and transverse loading were tested, verifying the displacements and the critical buckling load obtained.