FINITE-ELEMENT FORMULATION OF RIGID-BODY MOTION IN DYNAMIC ANALYSIS OF MECHANISMS

A new finite element model of obtaining equations of motion for rigid linkages is presented. The shape function for rigid mechanism motion a nd the resulting element inertia matrix are presented. The stiffness m atrix in the longitudinal direction is introduced in order to secure p roper displacements of finite element nodes. The equations of motion a re derived by using Lagrange's formulation and are integrated numerica lly. Illustrative examples of a robotic arm and a slider-crank mechani sm are presented and comparison is made with results obtained from cla ssical mechanics of rigid bodies. It appears that the finite element m odel presented is an efficient numerical method for analyzing rigid li nkages.