NUMARICAL ANALYSIS OF SIDEWAYS OVERTURNING OF AGRICULTURAL CARRIER WITH SAFETY FRAME ON A SLOPE

摘要

The purpose of this study is to develop a numerical tool to predict an effective height of a safety frame, or tip-over protective structure (TOPS), for agricultural carrier working on slope lands. The tool is based on a computer program for a tractor with protective structure [1]. For the purpose of application of the original program to agricultural carriers, we assumed two types of vehicles, one is four-wheel type and the other is three-wheel type. Moreover, to shorten the time of development, the main algorithm of computation in the original computer program was not modified in the currently developed tool for agricultural carriers. The vehicle was assumed to be safe when the succesive overturning was prevented by the sufficient height of TOPS. Based on data from a catalogue of four-wheeled agricultural carrier, the accuracy of developed tool was monitored, and the predicted height of TOPS was found to be understandable with respect to the dimension of the four-wheeled carrier. Moreover, the tool is then modifed to predict the optimum height of TOPS for three-wheeled carrier. We defined some characteristic points of contact in sideways overturning on a slope, and the axes of body rolling of the carrier were assumed. As a result, the height of TOPS for three-wheeled agricultural carrier also showed similar value to that for four-wheeled carrier.