The main goal of Truss Me! is to help students build intuition on how truss structures behave, and to understand how they fail through physics-based simulations.
A truss structure is composed of slender bars connected through joints. Joints are very important for truss structures, as they carry all weights (loads) and provide the connection points to the ground (constraints).
Truss Me! utilizes state of the art simulation techniques used by aerospace, mechanical, and civil engineers to provide the most realistic behavior for your structures. If well designed, your structures will resist as they would in real life*. If your design has flaws, the structure will fail realistically*!
Truss Me! is available for purchase on the App Store.
*Truss Me! has been created for educational and recreational purposes only. It must not be used under any circumstances to design or compute real structures.
All algorithms behind Truss Me! have been designed and implemented by Dr. Julian J. Rimoli, a professor of aerospace engineering in the area of structures and materials at one of the top graduate and undergraduate aerospace engineering programs in the United States. Dr. Rimoli specializes on designing computer models and algorithms to predict how materials and structures fail under a broad range of loads and environments.
Truss Me! has been designed using state of the art algorithms with the sole purpose of providing the most realistic behavior for the game. In this way, the intuition you build through trial and error using Truss Me! should be very accurate. Truss Me! looks like a game, but it is not just that. After mastering Truss Me! you should be able to see a truss structure in real life and have a good grasp on how its structural components are loaded*.
More specifically, Truss Me! is based on finite strain theory and can handle material and geometric nonlinearities, as well as dynamic failure of its members.
Material nonlinearities: in traditional engineering approaches, bars in truss structures are assumed to deform proportionally to the load applied on them. This is called a linear elastic behavior. In real life, this proportionality is only valid up to certain point, in which we say that the material in the bar starts to yield. As it reaches the yield point, the performance of the bar starts to decrease, reducing the stress to deformation ratio. Engineers call this effect plasticity. All bars in Truss Me! have an elastic-plastic behavior.
Geometric nonlinearities: in traditional linear approaches, all internal forces and reactions of truss structures are computed assuming that deformation of bars and displacements of joints are small. In Truss Me!, the response of the structure is computed on the deformed configuration to provide the most realistic behavior.
Dynamic failure: even the most advanced commercial software used to design truss structures generally do not account for advanced failure models. In Truss Me!, failure criteria is based upon the loading mode of the bars. For example, bars under tension (those bars which are being extended due to the overall deformation of the structure) fail after a certain critical plastic stretch has been reached. That is, they fail due to an inability of their material to carry further loads. Under compression (those bars which tend to become shorter due to the overall deformation of the structure), however, they fail due to a structural instability called buckling. Truss Me! reflects the reality that slender bars can withstand higher tensile than compressive loads before failing. This is done by considering failure under critical plastic stretch for bars under tension and buckling for those under compression.
Use Truss Me! to design and optimize the structure of a spacecraft for a safe moon landing!