Mechanics of Bulk Forage Deformation with Application to Wafering

Abstract

ABSTRACT THIS study deals with the stress-density behavior of bulk forages during compression in a cylindrical die, and with the cohesive strength associated with consolidated forages. A fundamental analysis of the deformation occurring during compression is included, and a theoretical model for the instantaneous density resulting from a given stress input is developed. The parameters are estimated from experiment. The ultimate density ymax did not depend on crop type or forage moisture content (ymax estimated to be 1415 kg/m3). Bulk stiffness was found to be sensitive to crop type, and to follow a nearly linear relationship with moisture content. The R2 value for all regressions studied was in excess of 0.90. A load constant parameter was introduced and found to be a useful indicator of the additional density likely to occur for increased stress input. Consolidated samples of alfalfa showed significant cohesive strength over grass samples up to 1000 kg/m3. The cohesive strength of consolidated grass varied in a quasi-parabolic manner with moisture content, and was maximum when moisture content was approximately 13.3% wb.