DISCRETE ELEMENT SIMULATIONS OF VIBRATION CHARACTERISTICS OF BULK GRAIN IN STORAGE BINS

A discrete element model (DEM) (Particle Flow Code, PFC3D) was constructed to simulate vibration of bulk solids in a bin filled with soybeans. The vibration frequencies and amplitudes of individual particles were determined from simulated particle velocities and displacements at different excitation frequencies and amplitudes. The simulated results were compared with experimental data obtained from model bin tests. The model bin of 0.28 m height and 0.15 m diameter was made of Plexiglas and filled with soybeans. The bin was vibrated at frequencies from 5 to 30 Hz and amplitudes from 0.2 to 5.0 mm. A high-speed digital imaging system was used to record particle movement along the bin wall during vibration. Simulated vibration of particles was in good agreement with the experimental data. Simulations revealed that particle vibration was simple harmonic and had the same frequency and amplitude as the excitation at low excitation frequencies and amplitudes. Particles vibrated at their own frequencies and amplitudes when the excitation frequency and amplitude were high. Both the DEM model simulations and the experimental data showed that particles not only vibrated locally but also moved globally.