Exact solution of stress and radial displacement of elastic tapered interference fit

Tapered interference fits, which can transfer large torques, are widely used in the connection design for propeller hubs and shafts of large vessels. In this paper, a model was developed to study the influences of torques, rotational speeds and tapers on the tapered interference fit between a propeller hub and a shaft. Using the classic elastic plane stress theory, the exact solutions of the radial stresses, tangential stresses and radial displacements of the propeller hub and shaft are derived. Then the calculation method of the magnitude of the tapered interference fit was presented. Finally taking a screw propeller system as an example, the above solutions were calculated using the numerical method. The results show that improving the stress distribution of the propeller hub is an effective approach to increase the connection strength and torque transmission capacity. If the rotation speed has to be considered, the stress and displacement would be increased significantly due to the centrifugal force. The present analytical solutions are expected to be useful in the structure design of tapered interference fits for propeller hubs and shafts.