A methodology for the development of stımulı-responsıve archıtectural desıgn systems through programmable metamaterıal patterns

Abstract

Conventional design and production approaches applied in architecture and construction sectors have a significant impact in global energy consumption and carbon emissions. Most of the energy is allocated to the building envelopes, and electromechanical control systems integrated into the building envelopes to provide indoor comfort by utilizing high energy consumption, complex mechanisms and costly maintenance processes. These systems are generally considered as "static". Due to the fact that some substances in nature may have also "active" characters that can respond to environmental factors by their specific material characteristics, this condition necessitates reconsidering conventional approaches. In this context, the concept of "active materiality" in the design process is addressed through three-dimensional (3D) and four-dimensional (4D) printing, material programming and smart materials. Another determining factor in the formation of active materiality is structural geometry. The geometric structure can directly affect the energy requirement of the system by facilitating the transformation process. At this point, "metamaterials" that have been artificially developed by humans in recent years and that exhibit superior mechanical properties come to the fore. The topologies, behavioral properties, interdisciplinary and architectural design applications of these structures are comparatively examined. By examining existing studies, it is observed that metamaterial patterns are predominantly utilized in static applications. However, these structures stand out for their capacity for dynamic transformation and the material intelligence they exhibit. In this context, gaps in the literature have been identified regarding the integration of metamaterial patterns with programmable structures for "active" use, the forms of this integration within design and fabrication processes, and their potential applications in architectural design systems. In response to these findings, this thesis aims to integrate metamaterial patterns with programmable materials to develop zero-energy, passive, and sustainable responsive architectural design systems. The methodological framework of this study consists of two stages: (1) generation of the metamaterial patterns and (2) integration of programmable materials into these patterns. In the first stage, a metamaterial pattern is developed that will allow dynamic transformations. Following this, a new pattern is designed computationally with obtained parameters. In order to test dynamic behavior of the system, two prototypes are produced by using Polylactic Acid and Thermoplastic Polyurethane materials that are rigid and flexible respectively. Then, the first experimental stage is undertaken where geometrical transformation is tested by applying forces to the prototypes from different axes. Deformations are recorded and measured. In the second phase of the methodological framework, a structural system, which can respond to its environment, is developed. Nitinol, a heat-sensitive alloy as a programmable material, is selected due to its accessibility and ease of application. The material is programmed to perform as a shading device on building facade. Geometric model is designed with 3D printed metamaterial patterns. In this direction, three variations are developed by using I, C and angled I-profile sections and they are printed by using Thermoplastic Polyurethane. Following this, an experimental setup is prepared, where the thermal conversion test is performed. This includes a heat-resistant glass container, hot water, thermometer, camera and lighting device. The samples are sequentially immersed in hot water and their transformations are tested and recorded with a camera. The module that performs better in these experiments is selected further for prototyping. In order to evaluate the potential of the selected system in architectural applications and to test its self-transformation, a 1:10 scale final prototype is produced. In this context, a section of the facade consisting of four modules is created by 3D printing. Textile material is integrated into the inner part of the modules to provide shading. The modules are placed in a structural frame made of aluminum profiles. Finally, the thermal conversion test is performed again and the resulting deformations are observed and recorded with a camera. The results are evaluated based on (1) pattern variations and (2) physical experiments and (3) the outputs. According to the findings obtained from the first experiment, where transformations were tested, metamaterial patterns exhibited different levels of deformations. In the experiments, where self-transformation was tested, the best result in terms of time use and transformation capabilities was the composite system with C-profile section. It was observed that the system was effectively activated by heat. The experiments carried out in 1:10 scale architectural prototype underlined the feasibility of the proposed methodology, despite the fact that uneven distribution of the heat on the surface prevented geometrical smoothness. Finally, a general evaluation of the outputs was made based on criteria such as time and form parameters, material and how well the research objectives were achieved by this study. As a result, responsive architectural systems through programmable metamaterials can be generated. In future studies, different shape memory alloys and patterns can be incorporated to the system. Additionally, 1:1 scale architectural applications can be utilized by using robotic fabrication techniques. Also, methods based on artificial intelligence can be integrated to the process. Thus, impact of the materials in the system sustainability can be evaluated more comprehensively.