The exploded view: A simple and intuitive approach to teaching the freebody diagram

One of the most fundamental concepts in all of mechanics is the free-body diagram (FBD) and teaching students how to draw the FBD correctly can be a fairly challenging prospect. In order to facilitate and unify the approach to drawing virtually any free-body diagram, the exploded-view method is presented in this paper. In short, the exploded-view approach is a four step process in which all the external forces and moments acting on the system are drawn, the particles and bodies in the system are separated from one another and any support, the knowns and unknowns are identified and the correct free-body diagram is selected for analysis. Three examples involving equilibrium of particles (2D and 3D) and equilibrium of rigid bodies (2D) are presented in the paper along with a comparison between the exploded-view approach and the methods employed by the authors of two different Statics textbooks. The dependability of this approach compared to traditional methods has been assessed based on its implementation in a section of a Statics class and the results are compared to that of a control group for a common Statics final exam and a Statics assessment in the Strength of Materials class in the following semester. Based on the results, there is a discernible improvement in the scores of students who were taught to analyze the FBD's using the exploded-view approach, even though a more comprehensive assessment is needed to study the veracity of this method in the long run.