Pressure Fluctuation in a Coal Hopper

Abstract

Wall pressures were measured during coal discharge from a hopper with a volume of 80m³. Power spectra of pressure fluctuations showed higher amplitudes distributed among frequencies below 10^-2Hz. The equation of motion was used to determine a stress-strain relationship of materials in a hopper that explains the cause of pressure fluctuations and their low frequencies.
A stress-strain relationship was found by analyzing stick-slip motion during the failure of materials, and this was illustrated by a hysteresis loop consisting of two different paths for compression and elongation.