Results are presented of an investigation of the one-pass performance of self-propelled vehicles in natural, weak, fine-grained soils for the following purposes: (1) to develop a reliable strength index for fine-grained soils with which predictions may be made of the performance of a vehicle on its first pass on a straight, level course, and a nominal vehicle load index to be used with the soil strength index to establish whether or not a vehicle will go; and (2) to provide means to predict one-pass drawbar pull and slope performance in soils having strengths in excess of the minimum required for one vehicle pass on level terrain, the increment of soil strength index necessary to permit a vehicle to maneuver freely, and the probable maximum speed of a vehicle operating in a terrain situation where the soil strength index exceeds the net vehicle load index. First-order answers are proposed to the five basic questions utilizing minor adaptations of techniques and concepts developed in the 50-pass trafficability work, and defining modified 'vehicle cone indices' (VCI1) and soil 'rating cone index' (RCI1) procedures appropriate to the one-pass problem. The ratio (VCI1/RCI1) is used as the basic soil loading numeric in simple approximate calculations of drawbar pull grade performance, soil strength increments necessary to permit free maneuvering, and probable maximum speeds, all as influenced by soil strengths.

THEORY OF GROUND VEHICLES A leading and authoritative text for advancing ground vehicle mobility Theory of Ground Vehicles, Fifth Edition presents updated and expanded coverage of the critical factors affecting the performance, handling, and ride essential to the development and design of road and off-road vehicles. Replacing internal combustion engines with zero-emission powerplants in ground vehicles to eliminate greenhouse gas emissions for curbing climate change has received worldwide attention by both the vehicle industry and governmental agencies. To enhance safety, traffic flow, and operating efficiency of road transport, automated driving systems have been under active development. With growing interest in the exploration of the Moon, Mars, and beyond, research in terramechanics for guiding the development of extraterrestrial rovers has been intensified. In this new edition, these and other topics of interest in the field of ground vehicle technology are explored, and technical data are updated. New features of this edition include: Expanded coverage of the fundamentals of electric drives, hybrid electric drives, and fuel cell technology Introduction to the classification and operating principles of the automated driving system and cooperative driving automation Applications of terramechanics to guiding the development of extraterrestrial rovers Elaboration on the approach to achieving the optimal operating efficiency of all-wheel drive off-road vehicles Introduction to updated ISO Standards for evaluating vehicle ride An updated and comprehensive text and reference for both the educational and professional communities, Theory of Ground Vehicles, Fifth Edition will prove invaluable to aspiring and practicing engineers seeking to solve real-world road and off-road vehicle mobility problems.