Considerations in the Internal Force Analysis of Slider-Crank Machines

In the analysis of internal forces for a slider–crank machine, writing the equations of motion is just the beginning. There are many engineering analysis decisions to be made regarding the handling of the crank angular acceleration, modeling of the connecting rod mass moment of inertia, and the approach to the solution of the resulting system of equations. Over the years, each of these have been handled in various ways, not all of then entirely correct. This paper looks at the various options and makes a critical review of the various practices. The intent is to encourage all engineering analysts to review the assumptions and methods of the software that they routinely use.