Mechanics of a Model Chisel Furrower

Abstract.

Design features of a model chisel furrower were subjected to standard soil mechanics equations to compare its performances in terms of draught or soil resistance force and soil coefficients with those obtained in a laboratory soil bin. Design features of the chisel furrower showed that it has the characteristics of a narrow tillage tool and therefore three-dimensional method of analysis was used. The calculations of draught and soil coefficients were carried out at three model tool widths (0.026, 0.51, 0.78 m) and nine levels of tool rake angles (10, 20, 30, 40, 50, 60, 70, 80, 90°). Results showed that soil failure angles decreased with increases in rake angles. Soil failure angles increased with increases in tool widths. The soil mechanics equations over predicted the soil resistance values slightly. The differences are however, not statistically significant. In order to get minimum draught, the model chisel furrower could be operated at rakes angles ranging from 40° to 50° and tool width of 0.051 m. The results obtained showed that the soil mechanics equations could be used to predict draught and soil coefficients on the model chisel furrower satisfactorily.