Numerical simulation and constructal design applied to stiffened plates with different height/thickness ratios

Abstract

Steel thin plates with stiffeners are largely used in naval structures, civil construction and aeronautics. The main characteristic of these plates is the low thickness value in relation to their width and length. The fundamental parameter in the analysis of these structures is their deflection when subjected to a load. In this research, rectangular plates with stiffeners, subjected to a uniformly distributed transverse load, were analyzed. The analytical calculation of these structures is complex and limited to simpler specific cases, so it is necessary to use computational modeling to determine the distribution of deflections. The numerical simulations were performed using the ANSYS® software, which uses the Finite Element Method (MEF), through the 8-node SHELL281 two-dimensional element with regular mesh formed by quadrilaterals. The different geometric configurations were determined using the Constructal Design Method, which transformed part of the thickness of a reference plate (without stiffeners) into stiffeners arranged in the longitudinal and transverse directions. These different geometric configurations were simulated numerically, through an evaluation by the exhaustive search technique, allowing the analysis of the influence of the geometric parameters in the plate's deflection. The results indicate that the increase in the height of the transverse stiffeners is more relevant than the longitudinal ones, implying in an improvement in the plate deflection resistance, in reference to the maximum and central displacements. Furthermore, optimized geometry resulted in a reduction of 97.92% in the maximum deflection and 98.81% in the central deflection in relation to the reference plate.