NON-LINEAR VISCOELASTIC BEHAVIOR DURING FORAGE WAFERING.

This paper describes the time dependent deformation characteristics which occur during the wafering of alfalfa and grass in a closed end cylindrical die. The efficient packaging of forage material into dense, stable and self-contained units requires an understanding of the effect of load and retention time on the bulk creep deformation. For this purpose, this study was conducted with a view to developing a suitable viscoelastic model for describing the rheological behavior of the material during wafering. Results show the viscoelastic behavior of the forages to be nonlinear. The creep compliance for grass and alfalfa was found to decrease significantly with increasing axial compressive stress and increasing moisture content. However, reducing applied load during wafering in favor of increased hold time was not found to be feasible.