Hysteresis in knurled interference fits

Abstract

Shaft-hub connections are an important feature of many machines, with knurled interference fits (KIFs) being a novel connection method. While conventional shaft-hub connections use either friction or form closure, KIFs represent a combination offering the advantages of both concepts. To investigate the behavior of such a connection, a computational model of a knurled interference fit is developed. Assuming rotational symmetry, modeling a periodic unit cell of the setup is sufficient. This assumption does not only greatly alleviate the demands on computing power, but also allows to analyze the hysteretic behavior of the connection in a phenomenological way. Parameter studies indicate changes in the transmissible loads and stiffness of the connection when varying geometric dimensions such as tooth height and angle, material and contact characteristics or applied loads. Notably, the hysteresis behavior of KIFs differs significantly from conventional connections like interference fits with smooth shaft-hub interfaces, particularly due to coupling between the radial and circumferential directions due to the tooth angle. Moreover, the simulations demonstrate that a certain stick–slip behavior may also occur in frictionless settings as a result of the geometry.