Analysis of static pressure distributions in grain silos with eccentric outlets. Rigid walls and elasto-plastic behavior of the stored material

Abstract

At the European level, silos are considered under the European Standards (Eurocode 1, Part 4. Actions in si/os and tanks), with no proposed method of calculation in the case of an eccentric outlet. The guidelines include a brief mention that eccentricity should not exceed 25% of the silo diameter and that in the future, attempts will be made to cover large eccentricities. We have developed an analysis of static pressure distributions in grain silos with eccentric outlets. To this end, silos were modelled using ANSYS 5.5. According to the F.E.M. maximum normal pressures on the silo wall correspond to the si/o-hopper junction. on the opposite side to the displacement of the outlet for any eccentricity, increasing at this point as hopper eccentricity rises. Compared to the Eurocode, static pressures are proposed when the hopper is centered and considered to be valid up to an eccentricity limit of 0.25 times the diameter , their redistribution at the hopper wall when this is eccentric may be observed by means of the FE.M. increasing on the opposite side to the outlet and decreasing on the same side with respect to the central hopper. This leads us to conclude that a more conservative method of calculation should be used in the Eurocode for normal pressures on the hopper wall when centered, and coefficients drawn up to include the variations produced in the static state when it is off-center.