Effect of the braking pressure variation on disc brake squeal of a railway vehicle: Test measurement and finite element analysis

In order to suppress or eliminate brake squeal of light rail trains, a field test measurement and a finite element analysis of disc brake squeal were carried out. In the field test measurement, the braking air pressure, speed of the axle, vibration accelerations of a backplate were measured. The brake squeal test was carried out in five brake conditions frequently used. Test results show that disc brake squeal generally occurred in the maximum common compound brake condition. The occurrence propensity of brake squeal depends on the variation of braking air pressure against time. A finite element model of the disc brake system was established, in which the friction coupling between the pad and disc was taken into account. A transient dynamics of the model was also studied using the measured braking air pressure data as an input of the model. The squeal frequency measured in the field test is in a good agreement with the finite element prediction result.