Fine analysis and size optimisation of spherical hinge in swivel construction

Abstract

Contact stress and friction torque are the two primary mechanical responses of a spherical hinge. In general engineering practice, the calculation methods for contact stress and friction in spherical hinges often involve simplifying the spherical hinge into a planar hinge. To accurately analyse the stress state of the spherical hinge, it is essential to establish a detailed model. In this study, 17 groups of spherical hinge models were developed. The support radius, curvature radius and thickness of the spherical hinge were considered influencing factors, while the maximum contact stress, friction torque and amount of steel used were treated as responses. A three-factor, three-level and three-response design was implemented. Using the response surface method, design optimisation was conducted, resulting in the proposal of two optimisation schemes (I and II). In schemes I and II, the maximum contact stress was reduced by 40.10% and 10.91%, respectively, while the friction torque was decreased by 0.82% and 26.50%, respectively. The maximum error between the predicted and calculated values was found to be 7.04%. This indicates that the model presented in this study possesses sufficient predictive accuracy and can effectively guide the selection of spherical hinge dimensions.