It is desirable for the rotors used in tillers to be shaped appropriately for the specific characteristics of soils in different regions. A technology for the prediction of the dynamic behavior of soils that makes it possible to study soils with varying characteristics on a computer is therefore demanded for the efficient design of tiller rotors.However, soil cultivation is a dynamic phenomenon involving the deformation, breakage, and agitation of the soil, and it is challenging for methods that use grids, such as the finite element methods and finite volume methods generally used in conventional CAE technologies, to treat phenomena of this type. The research discussed in this paper therefore attempted to develop a simulator for three-dimensional fluid-structure analysis using the particle method, a method suited to the analysis of large-scale deformation and breaking phenomena. In conducting this development, analytical accuracy was increased by reproducing the boundaries between soil and rigid bodies using polygons. In addition, to make it possible to faithfully reproduce the break-up behavior of soil, a model of soil break-up conditions that considered the effect of soil consolidation was formulated, and measurements of soil properties were conducted in order to provide input conditions for the simulation.Comparison of the results of simulations of a single tiller tine and an entire rotor with test results demonstrated that results matched for the break-up behavior of the soil and the shape of the plough pan. The simulator developed in the research discussed here has made it possible to reproduce soil cultivation on the desktop, and it is believed that it will be effective in helping to enable the efficient development of tillers.
Article of Honda R&D Technical Review Vol.24 No.1 (143 - 149)