Método dos elementos finitos e design construtal aplicados à flambagem elástica biaxial de placas retangulares com furo elíptico

Abstract

Thin steel plates are very important elements and are used in many areas of engineering. Thin plates can be considered a slender structural element, so when this element is subjected to a biaxial compression load, the phenomenon of elastic buckling can occur. One application of using a thin plate is when there is a perforation, which causes a redistribution of stresses in the plate, generating changes in its resistance and in the buckling characteristics. Therefore, this work proposes a study of the phenomenon of buckling by biaxial compression in steel plates with centralized elliptical perforation, simply supported. For this, numerical simulation was used, with the aid of ANSYS® software, to determine the critical buckling load. The Construtal Design method was applied, making it possible to qualitatively evaluate the effect generated by the elliptical perforation, as well as the influence of the variation of the relationship between the characteristic dimensions of the perforation on the mechanical behavior of the plates, verifying the best distribution of imperfections that leads the plate to its better performance. The plates were analyzed for predetermined volumetric fractions (Φ), this being the ratio between the volume of material removed and the volume of material on the plate without perforation. The analyzes showed that for each volumetric fraction a maximized critical load value was obtained, which leads to the optimal geometry. Comparing the critical load values obtained for the same Φ, there was an improvement of 68.32% for the optimal geometry (Φ = 0.10). Comparing between the different Φ, the best performance, for Φ =0.10; represents a 104.37% improvement in mechanical behavior when compared to the worst geometry of Φ =0.20. Keywords: Thin plates, biaxial elastic buckling, Finite Element Method, Constructal Design, volumetric fraction.