A semi-empirical equation to predict filling wall pressures on oblique conical hoppers

Abstract

. Hoppers are frequently used in steel silos, especially in farm facilities and food industries. These structures occasionally have an oblique hopper with an eccentric outlet to improve the flow of material during discharge. The 2006 version of the European standard EN 1991-4 uses classical Walker theory to predict wall pressures on concentric hoppers, but oblique hoppers are not considered. The authors have developed a Finite Element Model to predict the wall pressures on oblique hoppers and several sensitivity analyses have been made to study the possible influence of different parameters including outlet eccentricity, the outlet cir cumferential position, the aspect ratio of the silo and hopper, and different stored materials. The results show that the circumferential location and eccentricity of the outlet are the main factors affect ing the pressures on oblique hoppers. A semi-empirical equation is proposed to estimate the expected pressures on oblique hoppers which is designed to match with the maximum normal pressure obtained from the simulation, and to provide a good representation for the circumferential distribution of normal pressures. The results of this research may be of interest with regard to the upcoming revised version of the European standard EN 1991-4.