Elastic predictions of pressures in conical silo hoppers

Abstract

Theoretical techniques for predicting the pressures on the walls of conical silo hoppers have generally depended on the assumption that the mass of material within the hopper is in a plastic state of stress. The fact that this imposes considerable restrictions on the stress history and strain state has almost always been ignored. Moreover, few investigators have undertaken checks to verify the assumption. In this study, the alternative simple assumption is made that the material stored within the hopper is in an elastic state. The study is heuristic in character, as it is not claimed that an elastic state does exist within the hopper, though the assumption is not unreasonable for the initial filling condition. Nevertheless, a number of interesting discoveries are made about the stress distribution within the stored mass, and concerning the influence of various parameters on the hopper wall pressures. The analysis is conducted using a finite element analysis which includes the effects of hopper wall friction and hopper wall flexibility, and these influences are investigated.