This research develops constitutive relations and carries out a parametric study of internal forces generated in bulk material storage in large silos. A three-dimensional nonlinear finite element discretization analysis will be made with proper material characterization for loading and for unloading and material failure criteria and with a realistic representation of interface interaction (slip-stick) between the stored bulk material and silo wall. Verification of the analysis algorithm will be accomplished by comparing data obtained from analyzing pressure developed during symmetric and asymmetric flow initiation in the model silo, and from tests performed by varying the hopper angle, hopper configuration, discharge opening width, wall friction, bulk material constitutive relations, and segregation effects.