2023 ASEE Annual Conference & Exposition

A critical learning outcome of undergraduate engineering mechanics courses is the ability to understand how a structure's internal forces and bending moment will change in response to static and dynamic loads. One of the major challenges associated with both teaching and learning these concepts is the invisible nature of the internal effects. Although concentrated forces applied to the top of the beam can be easily visualized, observing the corresponding changes in the shear and bending moment diagrams is not a trivial task. Nonetheless, proficiency in this concept is vital for students to succeed in subsequent mechanics courses and, ultimately, as a professional practitioner.
One promising technology that can enable students to see the invisible internal effects is augmented reality (AR), where virtual or digital objects can be seen through a device such as a smart phone or headset. This paper describes the proof-of-concept development of a Unity®-based AR application called "AR Stairs" that allows students to visualize (in-situ) the relative magnitude of the internal bending moment in an actual structure. The app is specifically tailored to an existing 40-foot long, 16-foot high steel staircase structure located at the authors' institution. This paper details the application design, analysis assumptions, calculations, technical challenges encountered, development environment, and content development. The key features of the app are discussed, which include: (a) coordinate system identification and placement, (b) automatic mapping of a stairs model in-situ, (c) creation of a virtual 2-dimensional staircase model, (d) object detection and tracking of people moving on the stairs, (e) image recognition to approximate people's weight, (f) overlays of virtual force vectors onto moving people, and (g) use of a chromatic scale to visually convey the relative intensity of the internal bending moment at nodes spaced over the length of the structure.
It is the authors' intention to also provide the reader with an overall picture of the resources needed to develop AR applications for use in pedagogical settings, the design decision tradeoffs, and practical issues related to deployment. As AR technologies continually improve, they are expected to become an integral part of the pedagogical toolset used by engineering educators to improve the quality of education delivered to engineering students.