Abstract
Purpose. The study aims to establish the patterns of influence exerted by dynamic loads – arising from wheel-obstacle interactions – on a vehicle’s directional stability and handling performance. Methodology. To investigate the redistribution of vehicle weight over the wheels during obstacle impact, and to assess the effects of wheel – obstacle collisions at high speeds, a simulation-based approach was employed. This method is grounded in solving the Hertz contact problem. The dynamics of a low-speed vehicle encountering an obstacle were analyzed through the solution of the differential equations of motion. Additionally, a full-factorial experimental design was implemented to identify the critical factors affecting safe vehicle operation. Findings. The conducted study, which involved modeling obstacle impacts using inclined planes and cylindrical surfaces, revealed the redistribution of forces between two simultaneous contact zones – namely, between the wheel and both the road surface and the obstacle – as the low-speed vehicle progressed; it also clarified the variations in vehicle speed due to the longitudinal component of the obstacle reaction force, and assessed the impact interaction between the wheels and the obstacle and established the conditions under which wheel lift-off occurs, resulting in the loss of vehicle control. Experimental investigations were carried out using a specially developed test rig to analyze the dynamics of wheel rolling over a drive drum fitted with obstacles. Originality. The findings enable identification of the transition phase when a wheel shifts from contact with the road surface to the obstacle, during which dual-zone reaction forces act on the wheel. The study also establishes the patterns of variation in these reactions, the influence of obstacle resistance on the dynamics of low-speed vehicles, and the conditions that lead to wheel lift-off during impact with an obstacle – especially relevant for high-speed vehicles. Practical value. The results were experimentally validated using a custom-built test bench, which supports their practical application in determining optimal vehicle speed modes when traversing obstacles. These findings can also inform the design of artificial road irregularities (such as speed bumps) intended to enforce speed reduction in vehicles.