Simulação numérica das pressões exercidas pelos grãos nas paredes dos silos verticais pelo método dos elementos finitos.

Abstract

The silo, because it is a storage structure of products, involves several variables related to them and the interaction with the wall. In addition to these factors interfere in the determination of the loads acting, from the structural point of view, the stability of the silo must be studied considering the influences of the geometry and material when it is also in the state of deformation after the application of the loads, generating the effects of second order. In this context, comparing these data with the overpressure coefficients of different foreign standards for the case of discharge pressures, a very high number of possible combinations would be obtained, making an analytical or experimental study impossible if developed in a short period of time. By aiming at a broader scenario, the numerical simulation from the finite element method allows the discretization of the model in small divisions, in which the compatibility equations are obeyed by means of the boundary conditions. In order to improve the structural analysis of a silo, the research is based on the application of the finite element method through the ANSYS computational program to determine the pressures and deformations from the concentric discharge of the product stored on a slender metallic bottom silo plan. First, the computational model that simulates the discharge of products in a silo in the ANSYS was validated from experimental results obtained in previous researches, and from the comparison with the theoretical pressures obtained through the EUROCODE standard. From the model, silos were simulated, altering the variables thickness and slenderness, through the elastic and linear analysis and verified the necessity of a second order effect analysis, contemplating the effects of physical and geometric nonlinearity of the material. As the effect was not relevant, the critical buckling stresses were determined analytically by the membrane theory and the simulated shear stresses were compared. Only two of the five simulations obeyed the sizing criteria for rupture and buckling.