PREDICTING GRAIN CONSOLIDATION CAUSED BY VERTICAL VIBRATION
A theoretical model was developed to predict vibration induced grain consolidation (vertical settlement) in 
storage bins. In the theory, grain kernels were modeled as spheres connected by elastic springs and frictional dampers. 
Governing differential equations were then developed for this spring-damper system and solved numerically. It was 
hypothesized that grain consolidation was resulted from grain kernels being “pushed” into the adjacent layers by the 
inertial force during vibration. An experiment was conducted to measure grain consolidation in a small model bin filled 
with wheat to validate the predictive model. The bin was subjected to vibration at frequencies of 23, 30, and 48 Hz and 
amplitudes up to 2.3 mm. The predicted grain consolidation compared favorably with the experimental data. It was found 
that the maximum consolidation (density) was independent of the vibration frequency. However, the higher the frequency, 
the lower the amplitude at which the maximum consolidation (density) occurred. Both the vibration amplitude and 
frequency affected the variation of grain consolidation with the grain depth.