Research methods of car body design optimizing for improving vehicle vibroacoustic performances

Vibration loads have a great impact on the durability of the car and its comfort. The need to improve vibration protection systems, to conduct vibroacoustic analysis and develop new methods for optimizing vehicle vibrations as a whole is a modern and urgent task for the automotive industry.In the research work, we investigated vibration and noise problems associated with the integration of the transmission of the vehicle body, as defined methods to improve vibration isolation properties of the vehicle by optimizing vehicle body stiffness characteristics.The practical significance of the work is to identify recommendations for reducing the vibration loads transmitted to the driver, which will make it possible to make optimal technical decisions in the early stages of the development of the vehicle body.Using engineering analysis or combined methodologies, the process for optimizing the vibroacoustic characteristics of the vehicle should be based on a systematic approach and evaluate the appropriate compromise between a high level of safety, weight reduction, ensuring vehicle fuel economy and customer requirements such as controllability and vibroacoustic comfort.In the article, based on the analysis of literary sources, vibroacoustic phenomena associated with various transmission components and subsystems are identified. The frequency ranges and the nature of the displayed noise are established.It is established that the sensitivity to acoustic oscillations of the body is determined by the transfer function of vibration loads and noise from fastening elements (for example, axle bearings, transmission supports) to the body and vehicle control elements.One of the key performance indicators of a car body structure is its static and dynamic stiffness. To ensure good filtering of the vibration load, the local dynamic stiffness of the body in the installation zones must be several times higher than the corresponding rubber stiffness, and the natural frequencies of torsional vibrations of the body should not coincide with the natural frequencies of the unsprung mass and the frequency of the engine idle.