Measurement of friction phenomena on silo walls made of corrugated steel

This work investigates the friction generated by different materials (maize kernels, pinewood pellets and plastic pellets) on corrugated steel silo walls and examines the validity of the wall contact factor defined in Eurocode EN 1991–4 for estimating the frictional force on the vertical wall. A model silo was constructed with corrugated steel lateral walls, methacrylate front and back walls, and with a configurable base to set different discharge conditions. Normal and tangential forces at different heights on the silo walls were recorded, along with the mass flow index, to determine whether the flow of the material during discharge was greater with decreasing material particle size. An increase in normal and tangential forces was recorded for all materials tested during discharge, especially in the upper part of the silo. Pinewood pellets showed a greater mobilisation of internal friction as compared to plastic pellets and maize kernels.