Transient models for curve squeal noise

The paper deals with numerical models of railway wheel noise occurring in narrow curves. Curve squeal is presumed to issue from a lateral creepage of the wheels on the rail head. The frequency range is from around 400 to almost 8000Hz, with noise levels up to 120dB close to the wheel. Lateral friction forces are induced on the wheel–rail contact area (typically stick-slip forces). Due to nonlinearities of friction forces, a transient analysis of the lateral creepage of the wheel is performed by using an axi-harmonic model. Results give a reduced number of excited modes. It is shown that squealing modes have 3, 4 and 5 nodal diameters. These results agree with experimental investigations of squeal noise measurements. An extension of the transient model is finally discussed. It consists to study the efficiency of a noise attenuation system made of a metallic ring inserted into grooves machined into the wheel.