Vibratory analysis of tillage operation
A forced oscillatory soil cutting model was proposed with consideration for the energy requirement of the oscillator system and the soil cutting resistance related to the drawbar power of the tractor. A comparison between energy consumption in the cutting process for oscillatory and non-oscillatory cases was presented. Two sources of energy provide the required energy to the oscillatory soil cutting process: the oscillator driver and the tractor drawbar power. An optimum frequency was suggested for a given condition to realize a more effective soil cutting process. A tillage tool operating on agricultural soil was considered as a cantilever beam subjected to the fluctuating soil cutting resistance. A finite element model was developed to simulate the response of the deflection, velocity and acceleration of the shank and tillage tool when the soil resistance was applied at the end of the shank. It was found that the responses of the displacement, velocity and acceleration of the blade were associated with the natural frequency of the system and the applied frequency of the soil cutting resistance. It is known that the soil cutting resistance will cause movement of the tool. In turn, the position of the tillage tool will affect the soil cutting resistance. A transient soil cutting model was developed to obtain the relationship between the soil cutting resistance and the movement of the tillage tool. The values of the acceleration of the tillage tool calculated through the finite element method were compared with the results of soil bin measurements. There was a good correlation between the measurement data and the model estimation values. The verification of the model was in good agreement in terms of acceleration for the first few points of comparison. A higher sampling rate provided a better agreement between the test data and the model estimations.