Сельскохозяйственные машины и технологии (Oct 2016)
Theoretical and technological aspects of ripper working tools operation
Abstract
Operating of quality of cutivation of a deformable soil layer is important at soil cultivating working too use. The soil as cutivated object is characterized by elastic modulus, the Poisson ratio, ultimate compression strength, angle of wall and internal friction, coefficient of specific potential energy of destruction of soil particles. All these indicators depend on values of absolute humidity of the loamy soil. By means of a finite elements method the authors predicted an intense and deformable condition of the cultivted layer of the loamy soil taking into account such suppositions as a quasi solidity, quasi elasticity, constancy of speed and depth of cultivation. For realization of this method several operations were used, such as compiling of a global stiffness matrix, a load column, solve simultaneous linear equations, definition of possible movements of nodal points in the soil body across and verticals, and also determination of specific potential energy of elementary soil fragments. The load column is formed taking into account the gravity of soil fragments, traction resistance of a side surface of a chisel and a cutting edge, and also inertia forces. In case of comparison of the received values with the experimental rate of specific potential energy of destruction of soil fragments of the loamy soil it is possible to make the forecast about geometrical parameters of a destruction zone and extent of crumbling of soil fragments. So, at absolute humidity of the loamy soil 20.73 percent, speed of the movement of 1.6 m a second, depth of processing of 0.2 m, width of working tool of 0.02 m destruction zone length in the direction of the movement makes 0.12 m, width equals 0.1 m, the critical depth of cutting is 0.08 m. The coefficient of crumbling of a zone of the disturbed state does not exceed 22 percent.
