New formulation of imperfect cylindrical joints to perform dynamic analysis of multibody mechanical systems

Abstract

A computational methodology for dynamic analysis of multibody mechanical systems with imperfect cylindrical joints is presented and discussed in this work. Clearance and imperfections always exist in actual joints in order to ensure the correct relative motion between the connected bodies being the gap associated to them a result of machining tolerance, wear, and local deformations. Clearance at different joints is the source for impact forces, resulting in wear and tear of the joints, and consequently the degradation of the system performance. The model for cylindrical joints, presented in this work, is based on a thorough geometric description of contact conditions and on a continuous contact force model, which represents the impact forces. The existence of a clearance in a joint removes the four kinematic constraints associated with the ideal joint, and, hence, four extra degrees of freedom are introduced. When the journal reaches the bearing wall an impact takes place and contact forces control the dynamic of the joint.