A Soil-Tool Model Based on Limit Equilibrium Analysis

A mathematical model for predicting the behavior of narrow tillage tools in soils is based on a limit equilibrium analysis. Pertinent soil, tool and interface parameters influencing the tool performance have been identified and incorporated in the model. A comparison of predicted and experimental results is also included. Mathematical models based on emperical as well as semi-emperical methods have been developed to describe the soil-tillage tool interaction (Payne, 1956; Hettiaratchi and Reece, 1967; Hettiaratchi et al., 1966; Osman, 1964; Godwin and Spoor, 1977; McKyes, 1978; Desai et al., 1981). Even though the soil-tool interaction problem is three dimensional in nature, a majority of the models available are based on two-dimensional consideration (Hettiaratchi et al., 1966; Osman, 1964; Payne, 1956). In recent years some progress has been made toward the development of three dimensional models (Hettiaratchi and Reece, 1967; Godwin and Spoor, 1977; McKyes, 1978). However, most of these models are complex, and a sound mathematical background is essential to utilize them. Thus the need exists for more general and less complex models capable of predicting tillage-tool behavior in soils. Unlike costly experimental procedures, availability of such models would permit designers as well as researchers to develop with minimum effort a clear understanding of soil-tool interaction through parametric studies. Therefore, the overall objective of this study was to develop a generalized mathematical model and to examine its validity for predicting the tillage tool performance in soils..