Experimental analysis of wheel noise emission as a function of the contact point location

Recent analyses show that the wheel noise emission depends on the lateral position of the contact patch area on the wheel tyre. This displacement from the nominal position is such that different wheel modes are excited, resulting in a different frequency and amplitude composition of the wheel related noise component. In this paper the results of a test programme held on the ETR500 Italian high-speed train are shown. Thanks to a special device mounted under the axle box comprising a microphone and a windshield, it has been possible to measure the wheel noise continuously up to 300 km/h in tangent track and in curves. The behaviour of wheels in different condition of line curvature is shown, together with the results from a new type of constrained layer damped wheel.