Experiments on corn pressure in silo cells – translation and comment of Janssen's paper from 1895

Abstract

The German engineer H.A. Janssen gave one of the first accounts of the often peculiar behavior of granular material in a paper published in German in 1895. From simple experiments with corn he inferred the saturation of pressure with height in a granular system. Subsequently, Janssen derived the equivalent of the barometric formula for granular material from the main assumption that the walls carry part of the weight. The following is a translation of this article. The wording is chosen as close as possible to the original. While drawings are copied from the original, figures displaying data are redone for better readability. The translation is complemented by some bibliographical notes and an assessment of earlier work, wherein Hagen predicted the saturation of pressure with depth in 1852, and HuberBurnand demonstrated that saturation qualitatively as early as in 1829. We conclude with a brief discussion of more recent developments resting on Janssen's work.

Cohesive, frictional powders: contact models for tension

“…(If the walls would be frictional, the pressure from a certain wall would not be transferred completely to the respective opposite wall, since frictional forces carry part of the load-an effect that is known since the early work of Janssen [23,77,86].) Pressure-sintering is stopped when the kinetic energy of the sample is many orders of magnitude smaller than the potential energy-typically ten orders of magnitude.…”

Silo outflow of soft frictionless spheres

“…For comparison, we included the same measurement for peas (mean diameter 7.1 mm, density 1.35 g/cm 3 , friction coefficient 0.35 determined from the angle of repose and airsoft balls (diameter 5.88 mm, density 1.05 g/cm 3 ). There, the pressure saturates at fill heights of about 10 cm as a consequence of the Janssen effect [29,30]. The pressure at the bottom of the container filled with hydrogel spheres increases with fill height by p(h) ≈ h · 7000 N/m 3 .…”

Pressure and motion of dry sand: translation of Hagen’s paper from 1852

“…[6] -and offered a first model that provided a qualitative understanding of the effect. Hagen proposes a quadratic law (with some cutoff) for the pressure instead of the exponential form put forward by Janssen more than 40 years later [4,7].…”