An Experimental Investigation on the Modal Characteristics of an Off-Road Competition Vehicle Chassis

This paper presents the results of an experimental modal analysis performed on a prototype chassis of an off-road competition vehicle. The vehicle was designed by the Mini Baja EESC-USP team for the annual competition promoted by SAE Brasil. The goal of this experimental modal analysis is to validate a finite element model of the chassis, in order to develop a flexible multibody dynamic model of the complete vehicle. A preliminary finite element modal analysis of the test article was carried out in a free-free boundary condition. A random signal was used for FRFs acquisition. A multimode identification algorithm was used to acquire the system's modal parameters. Based on this information a swept sine was employed for mode shapes identification.