2024 ASEE Annual Conference & Exposition

Statics is a core course taken by undergraduate mechanical engineers in their freshmen or sophomore years. The course involves characterizing structures that remain still (static) under load. Statics concepts traditionally build in complexity from isolated particles, then to rigid bodies, and finally to structures formed by multiple rigid bodies. Structural analysis, otherwise known as “frames and machines,” is thus one of the more complex topics covered in Statics because it integrates prior knowledge of particle and rigid body equilibrium with new concepts like two-force members and internal loads. Traditionally, students become proficient in structural analysis by solving textbook problems where implicitly or explicitly, these problems classify the structure as either a “frame” or a “machine.” This classification in problem wording hints at the solution method and typically requires students to calculate the loads at a particular connector or cross section at risk of failure, thus reducing opportunities for structural analysis before computation. In actual practice, structural analysis is less straightforward; engineers must thoughtfully examine the structure to determine the best method of analysis and likely failure location(s).

Prior studies have introduced project-based learning (PBL) experiences for Statics courses that involve more realistic open-ended design, analysis, and validation. However, the prototyping component of these studies often falls short of actual practice by limiting students to scale model designs in craft grade materials, e.g., table-top sized bridges constructed from balsa wood. While economical and logistically simplistic, scale model designs do not reinforce industry-relevant design and fabrication skills, e.g., CAD/CAM and shop skills. Furthermore, scale models cannot be subjected to realistic loading conditions, which disconnects the analysis and validation portions of the project from actual engineering practice.

In this study, we introduce a novel PBL exercise – the Wooden Bike Frame Challenge – for Statics courses that focuses on structural analysis and involves fabrication of a full-scale wooden bike frame using CAD/CAM techniques. The complete set of instructional materials, including problem statements, assignments, and rubrics, are included in this study for open-source use by other engineering educators. We evaluated the efficacy of this exercise in reinforcing students’ knowledge of statics concepts and previously acquired prototyping skills using a mixed-methods approach. Study subjects were sophomore year mechanical engineering students who were teamed (n=158 students in 37 teams). The effect of the PBL exercise on content knowledge was determined by comparing pre- and post-PBL solutions to structural analysis textbook problems, as well as the more open-ended structural analysis of the bike frame designs. Post-PBL, students individually completed a survey assessing their level of engagement with the analytical and design aspects of the PBL exercise and perceived value of the project. The Wooden Bike Frame Challenge demonstrates the value of embedding full-scale design experiences into core courses like Statics, not only for strengthening newly acquired knowledge like structural analysis, but also for reinforcing industry-standard design and fabrication skills from prior coursework.