TRANSFORMABLE SPATIAL-BAR STRUCTURES: An Algorithmic Design and Evaluation Framework to Develop Free-Form Transformable Structures (FFTS).

This research aims to develop an algorithmic framework to design and evaluate free-form transformable spatial-bar structures (FFTS). Such structures can alter their forms into variable free-form geometries. To develop this framework, the research examined the history, typologies, and characteristics of transformable spatial-bar structures besides their design strategies, considerations and methodologies, and additionally reviewed the precedents relevant to FFTS. Afterwards, the framework was developed and assessed by means of digital and physical prototyping. Transformable spatial-bar structures are composed of reconfigurable linear elements (e.g. scissor pairs) assembled in three-dimensional configurations. They are commonly utilised in portable, deployable and transformable buildings. Their forms are mostly based on the modification of primitive geometries (e.g. sphere) through folding, sliding or rotation. Their movement commonly occurs within predefined series of states, for instance: from compacted to expanded (e.g. umbrellas). Since 1994, diverse precedents have been suggested to develop novel spatial-bar transformation typologies that can deliver free-form geometries (i.e. FFTS) for many architectural applications such as controlling solar gain, providing interactive kinetic forms, and control the users’ movement within architectural/urban spaces. Unfortunately, these FFTS precedents were poorly documented and were not implemented in architectural scale. Moreover, the precedents study revealed a list of technical and design issues that should be considered in the design and evaluation processes of FFTS. The available transformable design frameworks consider the evaluation of the structures in all their predictable movement states. These frameworks are not feasible in the case of FFTS, because the possible form variations of FFTS are infinite. This issue makes the evaluation process more complicated and require a unique approach that seamlessly generates and evaluates the forms of FFTS. Therefore, this research developed an algorithmic framework to integrate the design, forms generation, evaluation and operation processes of FFTS within a parametric design environment (i.e. Grasshopper). The framework incorporated parametric modelling, kinematic analysis, finite element simulations, and genetic algorithms to perform stochastic investigation and evaluation of the mechanical behaviour and robustness of randomly generated FFTS form variations. Additionally, the framework was employed to extract the design requirements of the components (i.e. bars and joints), and generate the data required for actuation after fabrication and assembly. The framework functionality was assessed by designing and evaluating an arbitrary 10x10m FFTS pavilion. Digital parametric and simulation models besides physical prototypes were utilised according to the requirements of each stage. The framework performed effectively, delivered the required outcomes and revealed some limitations and considerations that require further research work