Features of transportation of liquid or bulk cargo by vehicles on surfaces with a transverse slope

Abstract

The issue of improving the lateral stability of specialized vehicles designed for transporting liquids, especially when the tanks are partially filled, is discussed. Unlike the transportation of solid objects which location within the vehicle body remains static (with the exception of bulk solids) and that allows for a fairly accurate stability calculation since the center of mass of the cargo remains constant, transporting liquid cargo is associated with unique risks when driving on a road surface that deviates from the horizontal plane. The main cause of instability is the deviation of the center of mass of the liquid within the tank due to the occurrence of an additional overturning moment. To maintain lateral stability, the righting moment must be equal to or greater than the overturning moment. Experiments revealed a relationship between the tank fill level and the magnitude of the displacement of the liquid's center of mass at various critical vehicle inclination angles. It was found that with an increase of the critical inclination angle to 20°, the center of mass shifts by 0.1 m if the tank is only 40% full. With an increased fill level within the studied parameters, the center of gravity shift is reduced by a quarter (25%) which positively impacts lateral stability and improves the stability and maneuverability of the tank truck. It is also found that increasing the fill volume by 35% reduces the center of gravity shift by 18% enabling safe operation of the vehicle on roads with a slope by 12% higher than the standard. The obtained data allows simulating the stability of the vehicle under partial load while driving along a curve taking into account permissible longitudinal slope angles.