Railway wheels are secured onto the axle by means of an interference fit. The wheel is press fitted onto a pre-lubricated axle, and the resulting interference fit induces a contact pressure at the interface. Occasionally railway wheels fail by fatigue, with the initiation point for the failure frequently traced to the interference fit. The aim of this work is to use ultrasonic reflection to non-destructively determine contact conditions in the interference fit. ududThe rough surface contact at the interference fit interface behaves like a spring. If the contact pressure is high the interface is conformal with few air gaps, the stiffness is then high and the transmission of an ultrasonic wave is permitted. However, when pressure is low more air gaps exist, interfacial stiffness is then reduced and more of the ultrasound is reflected. udududNormalised contact pressure was determined from this stiffness. Maps of the interface have been produced which show the contact pressure to peak at the edges of the fit, and to experience a continuous variation about a mean value elsewhere.
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机译：铁路车轮通过过盈配合固定在车轴上。轮压装到预润滑的轴上，产生的过盈配合在界面上产生接触压力。有时，铁路车轮会因疲劳而失效，而失效的起点经常追溯到过盈配合。这项工作的目的是使用超声波反射以非破坏性的方式确定过盈配合中的接触条件。 ud ud过盈配合界面处的粗糙表面接触的行为类似于弹簧。如果接触压力高，则界面是保形的，几乎没有气隙，那么刚性就很高，并且允许超声波的传输。但是，当压力较低时，会存在更多的气隙，因此界面刚度会降低，并且会反射更多的超声波。 ud ud ud归一化的接触压力由该刚度确定。已经绘制出界面图，该图显示了接触压力在配合边缘达到峰值，并经历了其他位置平均值附近的连续变化。
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