Numerical analysis of overturning of a three-wheeled agricultural carrier with a safety frame on a slope

This study was conducted to develop a numerical program to predict the effective height and width of a safety frame, or tip-over protective structure (TOPS), for a three-wheeled agricultural carrier. To hasten program development, the main algorithm of computation in the original program for a tractor with protective structure laterally rolling over was not modified for this study. The target carrier was assumed to be safe when the successive rollover on the slope was prevented by the adoption of TOPS with sufficient height and width. Based on catalogue data of commercially available carrier, the accuracy of the developed program was investigated. Results showed a predicted height of TOPS that is reasonable with respect to the carrier dimensions. Then, a small carrier model was constructed to verify the accuracy of analysis by comparing the experimentally obtained result of overturning and the numerical result of the model carrier. Results showed that the developed program had qualitatively sufficient accuracy for predicting the TOPS height. For more precise prediction of the necessary TOPS height for three-wheeled agricultural carrier, a computer program based on the contact physics should be developed to include rolling or sliding of vehicles.