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AIXC-MAT-CS-001

Bulk material pressure on the wall and hopper of a silo

Fig. 1. DEM demonstration of discharge through a generic conical hopper: particle velocities on gate opening, wall pressure and discharge flow rate. Material calibrated against the cone test of Li et al. (2021) [1]. (1/3)Fig. 1. DEM demonstration of discharge through a generic conical hopper: particle velocities on gate opening, wall pressure and discharge flow rate. Material calibrated against the cone test of Li et al. (2021) [1]. (2/3)Fig. 1. DEM demonstration of discharge through a generic conical hopper: particle velocities on gate opening, wall pressure and discharge flow rate. Material calibrated against the cone test of Li et al. (2021) [1]. (3/3)
Fig. 1. DEM demonstration of discharge through a generic conical hopper: particle velocities on gate opening, wall pressure and discharge flow rate. Material calibrated against the cone test of Li et al. (2021) [1].
Question
What pressure does the bulk material put on the wall and the hopper during filling and discharge?
Method
EN 1991-4 as the basis of the calculation; DEM with implementación de referencia DEM and a material calibrated against the published slump test [1] for what the standard simplifies; finite elements for stiffeners and joints to EN 1993-1-9 and IIW.
Verify
+7 % / −2 % against the slump test of Li et al. (2021): slump 216 mm / 201 mm, spread 439 mm / 449 mm.
Result
DEM demonstration of discharge through a generic conical hopper: particle speed when the gate opens, wall pressure and discharge flow.
Limitations
DEM does not replace the standard. The wheat silo demonstration against EN 1991-4 is still being calculated. For each stored material, the DEM is calibrated with its own test.

Standards we work with

  • EN 1991-4We calculate to: actions on silos and tanks (stored material pressure)
  • EN 1993-1-9 · IIWWe calculate to: fatigue of welded joints (FAT curves, hot-spot method)
  • EN 1090-1 / EN 1090-2We support your certification: CE marking of structural steel components
  • What is the difference between tables and DEM?

    EN 1991-4 is the basis: it gives filling and discharge pressures, with patch loads and a procedure for eccentric discharge. DEM with a calibrated material is used to study what the standard simplifies, such as a specific hopper or outlet geometry, and to compare variants; it does not replace the standard. Our wheat silo demonstration against EN 1991-4 is being calculated. For each ensiloed material, DEM is calibrated with its own test.

  • Can I use my own finite-element software and have you calculate only the load?

    Yes. We can calculate only the load with DEM and deliver the force and pressure results for you to use in your own model. Or you can ask us for the complete analysis.

  • What data do you need for an existing silo?

    Drawings in DXF or STEP, steel grade and thicknesses, the stored material (particle size, bulk density, angle of repose) and the usual fill and discharge cycle.

  • Does the report count for the CE marking technical file?

    We calculate to EN 1991-4 and IIW. The report provides the calculation your technical file needs. Certification is issued by your certification body; we support your certification.

Propose a case

Describe your materials question in an email: the load of a bulk material, the fatigue of a weld, the wear of a plate or a clay blend. We will tell you whether it can become a case study and with which data.

Write to info@aixcresearch.com