Measurement of K-values in Diamondback Hoppers using pressure sensitive pads

Measurement of wall loads in hoppers has been difficult due to the expense of constructing multiple loads cell measurement units in a hopper. Recent advances in measurement techniques have allowed significant improvements in the measurement of multiple point normal stresses in hoppers. This paper presents measurements of wall stresses using pressure sensitive pads made by TekScan™. The wall stresses in a Diamondback Hopper™ were measured, indicating significant spatial stress variation. These hopper stresses were used to compute spatially varying K-values using a modified Janssen stress approach. The Janssen stress ratio approach with varying K-values that were a function of local hopper slope angle generated wall load curves that captured the general behavior of the observed wall loads.