Determining General and Overclosing Constraints in Mechanism Mobility Using Structural Finite Element Joint Freedoms

Abstract

Article presents the most general form of the mobility equation, and primarily describes general and three types of overclosing constraints. Then, it offers a method of determining numbers of the general and overclosing constraints in single and multiloop, planar and spatial mechanisms. It makes use of the number of external joint freedoms and the number of internal element end deformations in finite line element models of the mechanisms for force and torque analysis. The number of degrees of statical indeterminacy determines the number of constraints in the mobility equation. Redundant and passive freedoms, general, and overclosing constraints are determined for several single and multiloop mechanisms, including the Sarrutt’s, Bennett’s, and Bricard’s single loop mechanisms.