In conventional CAE (Computer Aided Engineering), methods using grids, such as the finite element method and the finite volume method, are commonly used. However grids are sometimes problematic in cases of dynamic free surface flows, with large deformation or breaking.
In this study, a novel three-dimensional fluid, structural analysis simulation program to reproduce the dynamic behavior of water or soil in the mechanical parts of a product equipped with a small engine was developed. This simulation program expresses water or soil as particles within boundaries having complicated configuration. These particles are then replaced with a polygon model to lower calculation load and to improve accuracy of configuration reproducibility. In the structural analysis, a breaking condition which considers the effect of soil compaction was designed to reproduce the break up of material with special characteristics such as soil.
Water splashing by an outboard engine was reproduced and the difference of two types of outboard engine configurations could be successfully expressed using the polygon model within the boundaries. Analytical results favorably corresponded to the experimental results qualitatively. Soil behavior by a tiller was reproduced and two different cases of breaking were analyzed. Break up behavior differed depending on whether the effect of breaking condition consolidation was considered. Break up behavior which considered the effect of breaking condition consolidation was closer to that obtained in the experiment
The simulation program developed for this study could successfully reproduce the dynamic behavior of water and soil and is considered to be effective in the development of a product equipped with a small engine.