The static contact statuses between granular materials and flat-bottomed steel silos

In this paper, finite element models have been developed to simulate the static contact statuses between granular materials and flat-bottomed steel silos in three forms: Near Contact, Sliding Contact and the Sticking Contact. The finite element models employ the Drucker–Prager yield criterion, which includes the volumetric dilation effects of granular materials. The static contact statuses are investigated with flat bottom steel silos containing different granular materials. The silo geometries vary at height/diameter ratios (H/D) of 0.75, 1.5 and 3.0. The granular materials are selected as coal, wheat, rounded gravel and sunflower seeds. Results show that the mechanical properties of granular materials (include bulk density, elastic modulus, Poissonʹs ratio, dilation angle, internal friction angle, cohesion) and silo designs (especially height/diameter ratio) have significant effects on the contact statuses at the interface between the granular materials and the silos. Since larger sticking/sliding contact area inevitably cause unloading difficulties or friction damage, contact statuses between the granular materials and the flat-bottomed steel silos should be optimized in the silo design in order to boost storing efficiency and economic benefit.