Nonlinear Finite Element Analysis of Farm Silos

A finite element formulation for nonlinear viscoelastic analysis has been synthesized with direct application to the problem of silage-silo interaction as a typical example of farm silo analysis. The formulation is based on basic theories in continuum mechanics and employs a single integral constitutive relation for nonlinear viscoelastic materials. This nonlinear formulation has been found, through its applications, to be a more versatile and accurate scheme when compared with the conventional piecewise-linear viscoelastic finite element formulations. Among the other features of the formulation are its capability of taking prescribed load, simulating incremental construction and its convenience in incorporating the silage-silo wall interface friction mechanism. The devised formulation was applied to predict stress histories, deformations, and resulting capacities produced during sequential loading of a 24x70-ft top unloading drained silo, using materials' constitutive functions that have been previously established through triaxial creep tests on corn silage.