Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
MODAL MAPPING AND MAIN TRANSFER FUNCTION ANALYSIS OF A SAE BAJA VEHICLE
Submission Author:
Abner da Silveira Alves , PB
Co-Authors:
Abner da Silveira Alves, Márcio Diniz da Silva, Antonio Almeida Silva
Presenter: Antonio Almeida Silva
doi://10.26678/ABCM.COBEM2023.COB2023-0582
Abstract
Excessive vibration can be more than an uncomfortable and deciding purchasing factor for the vehicle user. Could also be read like a warning or indicator of the vehicle behaviors. To avoid issues relating to excessive vibrations from the main sources, road and the engine, it is crucial to know the subsystems inherent frequencies, the most energetic excitation ranges, and the path though the vehicle. To understand and control the vibration response levels and guarantee the quality of the finished product. Different simulation models are utilized during the vehicle development and validation process, starting from the single components, and passing through sub-systems, systems, and entire vehicles. To prevent resonances and the harmful excessive vibration effects (loose bolts, component premature wear and drive discomfort feeling) it is important to map the component’s natural frequencies. The frequency map is one of the management tools used in the automotive industry. The primary goal is to reduce the resonance effects avoiding, as much as possible, the excitation range of sources and managing the different modes positioning to minimize potential modal coincidences. In this study, an off-road full vehicle model map was built using a simulation model. Parts of the vehicle were simplified, and the geometry of the main components was drawn in Autodesk Inventor®. The parts meshing and finite element model assemblage was all made on Altair Hypermesh® using diverse types of elements chose to better represent the geometry. For the Roll cage a high percentage of 2D Quads on tubes and a Trias elements in the welding joints. The frequency range studied was defined based on the main excitation order of a four-stroke single cylinder engine used in the Baja SAE competition. The engine on runup excitation was performed on inertial bench and the modal analysis between 0-150 Hz and the FRF was performed with Altair Optistruct®. The frequencies of some of the main subsystems were confirmed using frequency response functions (FRF). Furthermore, the frequency map was compared to the engine excitation curve to identify potential risks, the modes of the main components, and the transfer functions from engine to the steering wheel and the accelerator pedal.
Keywords
Baja SAE Vehicle, FEM, modal analysis, Modal Map Management
