A review of the finite element modelling techniques of soil tillage

Abstract

Both the analytical and the finite element method are being used to investigate soil cutting process. The finite element method is adequately contributing to the development of understanding the reality of this phenomenon. This method is used to predict soil stress distribution of different sorts, soil deformation, positions of soil failure and tool horizontal and vertical uplift forces. Two aspects are taken into consideration, namely soil mechanical behaviour and soil–tool interaction. The material behaviour and soil–metal interaction are of non-linear type. To simulate soil material behaviour under loading of tillage tools, two various theoretical bases are introduced, namely the curve-fitting technique and the elastic–perfectly plastic assumption. Soil–tool interaction is taken into account either as pure friction or friction with adhesion depending upon different influencing factors. Material and interaction properties used at the elastic–perfectly plastic assumption are usually considered constants, while at the curve-fitting technique their values are varied along with the loading path. At the curve-fitting technique large reduction in their values is made when the soil at a given nodal point fails in shear or tensile. This paper investigates the ability of applying these techniques of modelling to study soil tillage process. Brief comparison of results calculated by using both methods is introduced, as well. A review of several previous studies shows that both assumptions are adaptable to simulate soil material behaviour. However, the finite element method provides more accurate estimation of draught and uplift forces when the curve-fitting method is used. A reduction in the material and interaction properties should be made in order to improve the degree of accuracy when the elastic–perfectly plastic assumption is used.