A Viscoelastic Model for Forage Wafering

Abstract

New methods are being explored for consolidating loose forages into wafers. For this purpose a study of the compression characteristics of forages in a closed-end cylindrical die at high axial stresses was undertaken. A suitable rheological model for the wafering process is developed. It is shown that the commonly used four parameter linear model is adequate for characterizing the wafering process. A more advanced model with non-linear components has been found to be satisfactory. Results reveal that the instantaneous and viscoelastic material response are highly stress-dependent. Mathematical relationships for describing these deformation components are presented. The creep compliance was found to decrease significantly with increasing axial compressive stress. Substituting applied axial stress for load retention time in excess of one second to produce a wafer of specific density will not be feasible.