Experimental investigations on the wheel polygonalization
High speed not only shortens travel time but also brings out severe loads on every structure of vehicle system. As a rotating part the wheelsets are subjected to the most severe loads. As a result of that, wear of wheel would develop far more quickly than normal situation, and invariably become an out-of-round wheel representing a series of harmonic wear waves superposing along the wheel circumference. This special phenomenon of wear is also regarded as the wheel polygonalization. Knowing how wheel polygonalization develops in time history benefits a lot on manufacturing and operation. In order to obtain the development and growth of wheel polygonalization, long-term dynamics tracking tests were carried out. A train suffered from the wheel polygonalization running at speed of 300 km/h is taken as the representative. The major job is to measure the axle box acceleration via the accelerometers mounted on it and the circumferential wheel profile is measured by the special test equipment for wheel. By analyzing the data of both wheel profile and axle box acceleration, the polygonalization’s development in time history is identified and how wheel polygonalization influences the vibration of axle box is preliminarily known. It indicates that wheel polygonalization develops far more quickly in a short period rather than normal situation and polygonalization-induced considerable loads could contribute considerably to the vibration of axle box.