The development of prow and wedge type junctions in shrink-fitted torsion joints

Abstract

During an investigation into the torsional strengths of shrink-fitted joints some interesting features related to the interface friction of the joints were observed. These had a scuff-like appearance and junction growth with sliding was evident. Numerous scores which had not developed into scuffs may indicate that there are optimum load/contact area conditions for the initiation of scuffs. Scuffs and scores appear to be randomly distributed over the surfaces and not related to the stress distribution. A surface scratch on one surface can initiate scuffs on both mating surfaces. Owing to the strictly limited degree of freedom perpendicular to the surfaces, sliding conditions in a shrink fit are severe compared with those of a normal sliding pair. However, junction deformation appears to be similar to that found by Cocks & Antler in their investigations of junction shearing and development. But the junction growth is different and seems to be due to progressive shearing along spherical boundaries. There was no detectable evidence of junction welding between the shrink-fit components.