Novel methodology for isolating rotational phenomena in tire testing

Abstract

Due to electrification, tire/road noise is one of the key contributors to the vehicle noise performance. With the advent of component-based NVH representation, capturing the realistic dynamic behavior of the substructures is of primary interest for the industry. Tire dynamics are highly-subjected to changes due to operational conditions, such as preload, inflation, and rotating speed. Due to rotation, the standing wave pattern of a non-rotating tire mode shape can evolve into two opposite travelling waves with different natural frequencies, having the same mode shape. Separating the contributions of mode splitting due to rotation from mode splitting due to geometrical asymmetry caused by preload deformation is essential for a correct model validation. This paper presents a novel methodology for characterizing the modal behavior of rotating tires without contact patch deformation, observing rotational-only dependencies. By means of an original impact testing technique, a rubber sphere excites a free-spinning tire with constant energy at different velocities. By doing so, the changes due to pure rotational phenomena can be captured by contactless measurement devices, such as laser doppler vibrometer or high-speed cameras.