Vibration Analysis of an Automobile Using a Rigid Axle Moving on a Road Surface With Different Random Excitations

This paper presents the development of a model and the analysis of vehicle vibrations for a truck equipped with a rigid axle suspension system while traveling on a road surface subjected to random excitations with time-varying intensity and spectral characteristics. A half-vehicle vibration model in the horizontal transverse plane was developed for a light 1.5-ton truck with a rigid axle, incorporating five degrees of freedom corresponding to three primary moving masses: the rigid axle, the vehicle body, and the driver’s seat. The road surface excitations were simulated using a random signal with time-varying power spectral density to accurately represent the non-stationary and irregular nature of real-world road inputs. Through simulation and vibration analysis, weighted root mean square acceleration values were obtained at the axle, the vehicle body, and the driver’s seat. Vibration characteristics in the horizontal transverse plane were analyzed, and ride comfort at the driver’s seat was evaluated. The results indicate that variations in the spectral characteristics of the road excitations significantly affect ride comfort. As the excitation intensity increases, vibrations at the driver’s seat also increase, and vice versa. This is a key factor influencing driver comfort and safety. The findings provide a scientific basis for improving the design and optimizing the parameters of rigid axle suspension systems to enhance ride comfort and vehicle performance on rough and complex road surfaces.