World Journal of Agricultural Research, 2016, Vol. 4, No. 1, 24-30 Available online at http://pubs.sciepub.com/wjar/4/1/4 © Science and Education Publishing DOI:10.12691/wjar-4-1-4 Effect of Tine Depth and Width on Soil Failure Angle, Cutting Coefficients and Power in Three-Dimensional Case: Computer Modeling Moayad, B. Zaied 1 , Ahmed M. El Naim 2,* , Omer, A. Abdalla 3 , Abuobieda, M. Sulieman 4 1 Department of Agricultural Engineering, Faculty of Natural Resources and Environmental Studies, University of Kordofan, Elobied, Sudan 2 Department of Crop Sciences, Faculty of Natural Resources and Environmental Studies, University of Kordofan, Elobied, Sudan 3 Department of Agricultural Engineering, Faculty of Agriculture, University of Khartoum, Khartoum, Sudan 4 Department of Mechanical Engineering, Faculty of Engineering and Technical Studies, University of Kordofan, Elobied, Sudan *Corresponding author: naim17amn@yahoo.com Abstract The dynamic response of soil to farm implements is a main factor in determining their performance. The interaction between tillage tools and soil is of a primary interest to the design and use of these tools for soil manipulation. A computer simulation is conducted by developing a program using C ++ programming language to study effect of tool depth and width on angle of soil failure plane, soil cutting coefficients, soil resistance force and Power requirements in three-dimensional soil cutting. The results demonstrated that at 0.2 m tine depth the highest values of angle of soil failure plane, frictional coefficient, overburden coefficient, soil cohesion coefficient and soil adhesion coefficient were 52.6°, 19.8, 49.54, 16.47 and 1.38 respectively and they were recorded by 0.04 m tine width while the lowest values in same sequence were 51.6°, 10.64, 22.05, 7.26 and 1.30 and they were recorded by 0.1 m width. The lowest values of soil resistance force and power were 1.77 kN and 1.03 kW and they were shown by 0.04 m width while the highest values were 2.07 kN and 2.26 kW and they were demonstrated by 0.1 m width of tine. At 0.3 m tine depth the highest values of angle of soil failure plane, frictional coefficient, overburden coefficient, soil cohesion coefficient and soil adhesion coefficient were 52.7°, 27.42, 72.54, 24.11 and 1.39 respectively and they were recorded by 0.04 m tine width while the lowest values in same sequence were 52.3°, 13.70, 31.23, 10.35 and 1.35 and they were recorded by 0.1 m width. The lowest values of soil resistance force and power were 4.27 kN and 4.66 kW and they were shown by 0.04 m width while the highest values were 4.86 kN and 5.29 kW and they were demonstrated by 0.1 m width of tine. At 0.4 m tine depth the highest values of angle of soil failure plane, frictional coefficient, overburden coefficient, soil cohesion coefficient and soil adhesion coefficient were 52.8°, 35.04, 95.27, 31.73 and 1.39 respectively and they were recorded by 0.04 m tine width while the lowest values in same sequence were 52.5°, 16.75, 40.39, 13.40 and 1.37 and they were recorded by 0.1 m width. The lowest values of soil resistance force and power were 8.19 kN and 8.93 kW and they were shown by 0.04 m width while the highest values were 9.13 kN and 9.95 kW and they were demonstrated by 0.1 m width of tine. It was concluded that Angle of soil failure plane and soil cutting coefficients decreased as tine working depth and width increased. Soil resistance force and power increased as angle of soil failure plane and soil cutting coefficients decreased as tine working depth and width increased. Keywords: computer modeling, soil three dimensional cutting Cite This Article: Moayad, B. Zaied, Ahmed M. El Naim, Omer, A. Abdalla, and Abuobieda, M. Sulieman, “Effect of Tine Depth and Width on Soil Failure Angle, Cutting Coefficients and Power in Three-Dimensional Case: Computer Modeling.” World Journal of Agricultural Research, vol. 4, no. 1 (2016): 24-30. doi: 10.12691/wjar-4-1-4. 1. Introduction Limit equilibrium is one of the most important approaches used to analyze soil–tool systems. Two most important factors in the approach are the shape of soil failure surface, and equilibrium equations, which are two or three dimensional cases. Several mathematical models have been developed for predicting the performance characteristics of tillage tools in soils. These include two-dimensional models for wide tools and three dimensional models for narrow tillage tools. Payne's model [1] was the first three- dimensional soil failure model By observing the top surface soil heave during tillage, a failure zone was proposed The failure zone included a triangular centre wedge, a centre crescent, and two side blocks (called wings of the crescent). Extensive tests were conducted by Payne and Tanner [2] to study the effects of the failure zone size and the rake angle on the draft force. However, no equations were developed to evaluate the draft force for narrow tillage tools. The analysis of three-dimensional failure assumes