Rolling friction torque generated by time delay during stress wave transmission

Abstract

A new type of rolling resistance was discovered in Shinkansen trains. Rolling resistance at 300 km/h is four times larger than at low speeds. This increased part of the rolling resistance is proportional to the train’s speed. The reason is currently unknown. This paper makes it clear. The stress in the contact area travels upwards and reaches the axle with some delay. The delay time affects the stress distribution at a high speed running. The 3D-distributed stress approximately satisfies recurrence equations that can be solved numerically. The result reveals that the stress distribution is shifted forward from just below the wheel center. The frictional resistance calculated by this theory agrees well with the experimental values measured on Shinkansen 700 series.