Effects of rake angle of chisel plough on soil cutting factors and power requirements: a computer simulation.

摘要

A computer simulation was conducted to predict the effects of rake angle of a chisel plough and soil bulk density on angle of soil failure plane, rupture distance, width of side crescent, frictional, overburden, cohesion and adhesion soil cutting factors, draft forces and drawbar power requirements. The experimental work was carried out in two locations. Soil of the first location was sandy clay with the soil bulk densities of 1.75 and 1.70 g/cm3 for firm and loose soil conditions, respectively, with an angle of internal friction of 30 degrees and a surface friction angle of 20 degrees , cohesion of 2.5 kN/m2 and adhesion of 1.2 kN/m2. Soil of the second location was clay loam with the soil bulk densities of 1.65 and 1.50 g/cm3 for firm and loose soil conditions, respectively, with an angle of internal friction of 34 degrees and a surface friction angle of 23 degrees , cohesion of 2.4 kN/m2 and adhesion of 1.14 kN/m2. The prediction showed that the angle of failure plane found to decrease with the rake angle. The rupture distance decreased with the rake angle from 15 degrees to 55 degrees and then increased as the rake angle increased over 55 degrees . The width of the side crescent increased as the rake angle increased and the maximum value and the minimum value were recorded at 75 degrees and at 15 degrees . Values of frictional and overburden factors decreased as rake angle increased. The maximum and minimum values were recorded at 15 degrees and 75 degrees , respectively. The values of cohesion factor increased as rake angle increased. The maximum value was recorded at rake angle of 75 degrees and the minimum value was recorded at rake angle of 15 degrees . Adhesion factor was found to change inversely with the rake angle from 15 degrees to 55 degrees and then to change directly with the rake angle over 55 degrees . The draft force decreased with the rake angle and reached its minimum value at 45 degrees rake angle. Over 45 degrees , the draft force increased and reached its maximum value at 75 degrees rake angle. The draft increased with soil bulk density. The power required for moving the plough recorded the maximum value at rake angle of 15 degrees , while the minimum value was recorded at 55 degrees rake angle. The values of power increased with decrease of soil bulk density. The predicted values demonstrated some deviations from the experimental values of the draft force and the drawbar power..