chapter  7
48 Pages

Dynamic Force Analysis of Planar Mechanisms

WithKevin Russell, Qiong Shen, Raj S. Sodhi

This chapter begins with the formulation of a dynamic force equation system for the geared five-bar mechanism by first formulating a dynamic force equation system for a five-bar mechanism without gears. It explains criteria for dynamic force analysis and its applications, link dynamic loads in 2D space, and formulation and solution of linear simultaneous equation sets for dynamic force analysis. The chapter discusses the effects of gear train inclusion in the dynamic force analysis of five-bar mechanisms, the mass moment of inertia, its application in dynamic force analysis, and its calculation in computer-aided design (CAD) software. It formulates a system of dynamic force and moment equations of the planar four-bar, slider-crank, geared five-bar, Watt II, and Stephenson III mechanisms. Dynamic force analyses are also more general than static force analyses when mechanism motion is quasi-static. In a mechanism where the crank link rotates continuously, nonconstant force profiles in the mechanism joints will cause the mechanism to oscillate or vibrate.