Propriedades físicas e de fluxo de milho com diferentes teores de umidade para o cálculo de pressões em silos metálicos.

Abstract

Brazil is the third-largest producer of maize in the world, and one of the main stages after harvest is storage, influenced among many factors by the moisture content of the grains. This work aims to determine the physical and flow properties of maize as well as the analytical determination of the pressures exerted on the walls of slender vertical metallic silos. The studied properties were obtained through tests carried out with the direct shear apparatus “Jenike Shear Cell”. The calculations of horizontal, vertical, and wall friction pressures for loading and unloading were performed using the American standard ANSI/ASAE EP433. The average flow function decreased its value with the increase of humidity, increasing the cohesion between the particles. The internal friction angles and effective internal friction angles showed little variation with the change in humidity. The wall friction angles and hopper tilt angles increased in direct proportion to the increase in humidity, while the flow factor decreased smoothly. As for the pressures, the increase in the moisture content changed the consolidated specific weight of the stored grains, proportionally interfering in the value of the pressures exerted inside the silo, which could compromise its structural safety.