In previous studies, it was found that a tire’s fundamental air-cavity mode, typically near 200 Hz for current passenger car tires, splits into two features when the tire is loaded. Since the deformed tire is no longer geometrically symmetric, separate fore-aft and vertical modes appear, the former mode appearing at a slightly lower frequency than the vertical mode. These modes are key contributors to dynamic loads on the suspension system and consequently on cabin noise near 200 Hz. In this context, measurements of the dispersion relations for a set of loaded tires were performed to investigate the range of magnitudes of the modal frequency split. Also, finite element analysis of a tire was deployed to model the dispersion in the vicinity of the fundamental air cavity mode. Splits ranging from approximately 3 Hz to 12 Hz at rated load were identified, and it has also been found that the magnitude of the frequency split for a given tire shows a low order polynomial relationship to the applied load.
Tire Noise, Acoustic cavity mode, Frequency split, Loaded tire, Dispersion relations
Acoustics and Noise Control
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