A MICROSTRUCTURAL MECHANICS MODEL FOR PREDICTING HYGROSCOPIC LOADS IN GRAIN STORAGE BINS

A two-dimensional microstructural mechanics model has been developed for predicting hygroscopic (moisture induced) loads in grain storage bins. The model assumes that the grain bulk consists of elastic spherical kernels. The volumetric expansion of a grain kernel is approximated by the volume of water absorbed by the kernel. Hygroscopic microstresses are calculated from moisture induced microstrains which are determined from the volumetric expansion of the kernel. The microstructural mechanics theory is used to transfer these hygroscopic microstresses into macroscopic stresses (or hygroscopic pressures) on the bin wall. Predicted hygroscopic loads are in close agreement (within 6%) with the reported experimental data.