Sound generation mechanism in flexible cylindrical structures undergoing rotation and contact

In recent years, tire noise has become a significant source of noise in automobiles. This phenomenon, in which structures generate sound through rotation and contact, is also widespread in industrial applications, including train wheels, rollers, and bearings. Therefore, a deep understanding of their vibration and noise generation mechanisms is crucial for enhancing performance, ensuring durability, and improving comfort. This study focuses on flexible cylindrical structures where rotational motion and ground contact occur simultaneously. Our primary objective is to clarify the vibration and noise mechanisms arising from the interaction of elastic deformation, contact, and friction. To investigate the vibration modes and noise frequency response for various parameters like rotational speed and force, experimental equipment was developed where a cylinder rolls on a base. The deformation near the contact patch was filmed and visualized using image analysis for each parameter, and the frequency response of the generated sound was measured. By comparing the observed deformation patterns with the sound response, it was investigated how each parameter influences vibration. Our results show that increasing load and rotational speed leads to greater vertical vibration amplitude during ground contact, accompanied by an increase in the high-frequency components of the generated sound.