Bedding effects in bulk solids in silos: experiments and a polar hypoplastic approach

This paper is concerned with bedding effects in granular bulk solids in sil os. Finite element (FE)-analyses were performed for a cylindrical thin-wall ed steel model silo with imperfections containing dry sand. Numerical calcu lations were carried out for an axisymmetric case with a polar hypoplastic constitutive relation which can capture the salient properties of granular materials. In the FE-calculations, different types of wall displacements al ong the silo height were taken into account to model roughly the formation of buckles due to initial imperfections of the silo wall. The effects of th e initial void ratio and mean grain diameter of bulk solids, initial stress state, wall roughness, and size and form of buckles were studied. The nume rical results clearly show that the modelling of a bedding effect of bulk s olids in silos by means of springs is too simple and can lead to strongly u nrealistic predictions of the bedding modulus. (C) 2000 Elsevier Science Lt d. All rights reserved.