Teaching Structural Behavior with a Physics Engine

The paper describes a project which uses a novel non-linear computational method to teach structural topics ranging from elementary statics to plastic analysis of beams, and frame buckling. The project centers around a computer program, called Arcade, developed using a computational method, called a physics engine, which has been widely used in computer games. This method has two special characteristics with respect to structural behavior: it can model unstable structures, and it performs all calculations with respect to deformed geometry. In addition, the method can perform calculations in real time, so the on-screen structure responds instantly to loads and other actions induced by mouse clicks and key strokes. These characteristics allow the program to show the effect of forces on free-floating bodies, which is ideal for demonstrating free-body diagrams. Combined with elastic beam and truss elements, the method can model cable structures, elastic column buckling, and kinematic mechanisms that result from unstable configurations of supports and internal releases. Used with inelastic beam elements, the program can model plastic collapse mechanisms of beams and frames. The paper describes examples and exercises which have been used with the program in architecture and engineering courses at the University of Virginia.