Investigation of the dynamics of the vibrating system of a moving vehicle

Abstract

Abstract. The paper presents a study of the dynamics of oscillations of the GAZ A31R32 vehicle under the influence of road irregularities. The dynamics of vehicle oscillations caused by road irregularities is a relevant issue, as it has a significant impact on its ride comfort, handling, and stability. Therefore, in order to solve the problem of the dynamics of the oscillatory system of a moving vehicle, a mathematical model of its dynamics was developed; this model makes it possible to study the elastic‑damping properties of the suspension with constant, variable, and adjustable parameters. At the same time, it is a four‑axis five‑mass dynamic model adapted for studying the oscillations of roll, pitch, and the vertical displacement of the center of gravity of the reference vehicle during braking and acceleration. Moreover, the car is considered as an oscillatory system consisting of several masses connected to each other by elastic‑damping links. For the dynamic model, the car body is considered as one large sprung mass that experiences vertical displacement. At the same time, the presented model also takes into account the influence of unsprung masses and the elastic characteristics of the tire, where all four wheels are modeled as a separate unsprung mass with its own vertical movements. The results obtained through modeling the oscillatory system of the test vehicle show that, overall, the suspension’s elastic‑damping properties provide an acceptable level of ride smoothness within just a few oscillation periods. However, at the initial stage, fairly significant amplitudes are observed, which negatively affects the ride smoothness. This situation arises due to the impact of road irregularities on the vehicle’s suspension system and confirms the need to improve its suspension system.