Reduction of tire road noise is an important issue when developing luxury cars and electric vehicles. In this context, the air cavity mode is an important source of spindle forces transmitted to the suspension that then increase interior noise levels. When a tire rotates, the cavity mode near 200 Hz splits into two adjacent modes due to a Doppler effect and tire deformation. That split can lead to increased levels of both longitudinal and vertical spindle forces at the spindle since the two acoustic modes each contribute to both forces when the tire rotates. Thus, it is important to develop tools to identify the contributions of the split air cavity modes to the spindle force. A FE simulation of the spindle force for a steady state rolling tire has been verified by a comparison with laboratory test results obtained by using a wheel force transducer mounted on Purdue’s Tire Pavement Test Apparatus. It was observed that the frequency split expands as the rotation speed increases and that the vertical spindle force increases when aligned with an odd numbered circumferential structural mode.
Tire Noise, Acoustic cavity mode, Frequency split, Loaded tire, Dispersion relations, Finite element modeling
Acoustics and Noise Control
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