The Exploded View: A Simple and Intuitive Approach to Teaching the Free-body Diagram

Abstract

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.

Good Strategies to Avoid Bad FBDs

“…Another strategy (a short description of the exploded view approach) [22] Finally, we will discuss one additional proposed strategy for drawing FBDs called the "exploded view approach." This approach is not a completely new concept; it is merely an extension of the general methodology used to evaluate trusses, frames and machines to virtually every mechanical system.…”

“…Figure 5. Example of the exploded view approach to drawing FBDs [22] Survey results A survey was developed to get feedback on elements of free-body diagrams (FBDs) and mnemonics for drawing FBDs (see Appendix B). Respondents were asked about the importance of including the five elements identified from Statics books earlier in this paper.…”

WIP: Toward a Free-Body Diagram Mobile Application

“…A large body of research has developed around FBD instruction and assessment [9]. Recent innovations include hand-drawn FBD instruction, such as the exploded-view technique [10], and the use of hands-on exercises that allow students to feel forces and moments as they construct FBDs [11][12][13]. These improvements to FBD instruction have undoubtedly improved the undergraduate learning experience, but students still struggle.…”

Some thoughts for teaching engineering statics

“…Engineering statics is a very important course for any mechanical engineering program. Lots of literature proposed and implemented different approaches to facilitate students to be successful in engineering statics, such as mechanical breadboard [1], different teaching styling [5], hands-on design project [6], sketch tool in SolidWorks [7], applying numerical modeling techniques [8], animated GIF files [9], task-analysis-guided deliberate practice [10], the explored view [11] and the inquiry-based approach [12], etc.…”