Thesis Defence: Richard Mui

Complex frames are ,difficult to model because: there are so many elements, redundant load paths, and require unreasonable amounts of computing power to run simulations on. In order to explore the realm of complex frames, there needs to be a technique for approximate modelling to allow for rapid analysis with dependable accuracy. This thesis proposes the Polygon Tessellation to Approximate Frame (PTAF) method for rapid structural analysis of the Living Architecture Systems (LAS) group’s complex frames.

The PTAF method uses the LAS compositional design process polygons as inputs for a parametric script that generates a simplified frame model. This model can be used for Finite Element Analysis (FEA) because it has perfect connectivity. By simplifying the model, the analysis can be run quickly on conventional computer hardware. In this way, structural performance can be evaluated without significant time investment. Especially in the early stages of the design process, it is important to quickly receive reasonably accurate predictions of performance because the design is constantly evolving.

To simplify the model, each component of the frame were reduced to a few beam elements that closely approximate the behaviour of much more accurate models. The process of linear FEA relates the force exerted on a model to the displacement it will undergo by its stiffness. The detailed and coarse models were subjected to the same support and loading conditions so that the displacement could be measured, and a function of error between the two displacements could be made. By minimizing the error between detailed and course models, values for the equivalent stiffness of each component can be arrived at. By the theory of finite elements, it is assumed that behaviour at component scale is indicative of behaviour at the global scale. In this way, the global simplified model will approximate the behaviour of the actual structure.

This research commenced through collaboration with the LAS on the Luddy Hall installation. The goal of the collaboration was to add value to the project through the addition of structural analysis in the design process.The frame of Amatria was immensely complex, full analysis of the frame would be prohibitively expensive, and add an unreasonable amount of time to the design process. This research was able to benefit the project by analyzing key components to ensure adequate strength and stiffness to facilitate ease of construction. Lessons learned from this projected helped inform method development.

This research provided the possibility of self supporting structures, based on the system of components currently being used in LAS testbeds. A pavilion study was used as a thought experiment of how the combination of parametric modeling and approximate analysis could be used to design a free standing pavilion from typical LAS produced components. Participation in future testbeds will undoubtedly provide invaluable information to refine this method.