R Jafari - Department of Biosystems Engineering, College of Agriculture, Jahrom University, Jahrom, I. R. Iran
T. TavakoliHashjin - Department of Mechanics of Agricultural Machinery, College of Agriculture, TarbiatModares University,Tehran, I. R. Iran

ABSTRACT-This paper aims to develop a new design of a bentleg (BL) plow and to determine its performance as compared to the conventional one using finite element approach. The difference between the modified and conventional BL plows is the direction of angle between the projection of cutting blade on horizontal plane normal to plow shank and the line perpendicular to the plow shank in the same plane. The conventional (B۱), and modified (B۲) designs of BL plow were modeled at three rake angles R۱= ۷.۵°, R۲= ۱۵° and R۳= ۲۲.۵°. A three dimensional nonlinear finite element model was applied using ANSYS ۸.۱, ۲۰۰۴. The variation of calculated draft force by model indicated that minimum and maximum draft forces were obtained for B۲R۲ and B۱R۳ treatments, respectively. The minimum vertical force was measured for B۱R۱ treatment. Calculated draft and vertical forces were in good agreement with measured ones. An increasing positive x-y shear stress zone in the modified BL plow causes the soil lifting increase as compared to the conventional one. Similarities of the Von Mises stress contours to stress characteristic curves emphasize the validity of the analysis. The small size of the plastic Von Mises strain contours (plastic bubble) in the modified plow emphasizes the fact that the force requirement of the modified BL plow is less than that of the conventional one. Similarity of the stress distribution contours in soil block and the stress characteristic curves show the validity of the modeling.

Keywords:, Bentlegplow, Draft forces, Vertical force, Soil displacement