YAMANAYA Shoichiro KYUSHU UNIV., DEPT. AGR. ENG., RESEARCH ASSISTANT, 農学部, 助手 (20038251)
INOUE Eiji KYUSHU UNIV., DEPT. AGR. ENG., ASSOCIATE PROFESSOR, 農学部, 助教授 (00184739)
UENO Masami UNIV. RYUKYUS, DEPT. AGR. ENG., ASSOCIATE PROFESSOR, 農学部, 助教授 (50145546)
In order to study the traveling performance of off-road vechicles, various types of apparatus measuring mechanical quantities of a traveling performance on a soft ground have been developed in the past. They have not achieved, however, a satisfactory accuracy as yet, while it is difficult to provide a driving torque to a wheel, maintaining a constant contact load between a wheel and soils. In this study, a new apparatus was developed, which is capable of measuring the basic mechanical quantities, i.e. torque, contact load, drawbar-pull, normal and tangential stresses on the wheel surface and the deformation of soil under a constant contact load with high accuracy. Most of these quantities are visualized on an on-line computer display. Further, a finite element program based on the subloading surface model of elasto-plasticity has been developed to analyze the soil deformation by the rotation of a rigid wheel. The main features of this program are to analyze suitably the elastoplastic deformation of soil, to describe realistically the boundary condition at the contact surface between the wheel and the soil, incorporating the Coulomb's friction law, and to keep the contact load constant automatically. Besides, it consists of two stages, i.e. the sinkage stage in which a wheel goes down vertically and the rolling stage in which a whee travels rolling. The comparison of the calculated results with the test data verified that the analysis by this program can describe qualitatively the general tendency of the test data but is required a modification for the quantitative prediction of traveling performance of wheel.