Architecture is emerging into the information sector where technology and built environment are together creating a new paradigm of design. This new model of design is not only sensitive towards the changing situations with time but also has the capacity to actively identify problems and opportunities and respond to them. This practise of designing active solutions depending on technology has proven to be immensely effective but requires a lot of energy to function. Also, it has set itself apart on a new path, further away from the passive traditional solutions in architecture, thus creating an ever increasing gap between technology and passiveness.
Self-adaptive Membrane is a project developed by Nohelia Gonzalez and Shreyas More to introduce a new technique which unifies the gap between the active performance and passive strategies of architecture. The study involves scientific investigation of the shape memory alloy – Nitinol to develop a passive kinetic motor which is capable of deploying geometries in response to the presence of solar radiation.
Shape Memory Nitinol alloy (SMA) is a smart material which possesses the ability to deform at low temperatures, and transform into the programed shape at actuation temperature. A commercial Nitinol spring, with actuation temperature of 750-850 C, has the ability to pull up to forces of 16N per 20mm of length of spring which is capitalized to design a strong joint.
The Nitinol-Zinc combination, based on this principle, contracts and expands the nitinol by the external force of zinc spring in the presence and absence of high temperatures. This creates a loop displacement motion of an independent mobile mechanism. This is inspired by the project Smart Screen by Decker and Yeadon and the research is an extension to their findings to construct an amplified passive change. The transforming property is used to test the balance of strength by using different lengths of nitinol and zinc spring to achieve maximum displacement.
Self-adaptive Membrane has two vital performative components: 1. The kinetic Nitinol joints and 2. The folding tessellation geometry; working together as an integrated system. To increase the internal temperature, the joint is subjected through various colours and material tests. Black Joint, being heat absorptive, shows maximum displacement in the system while the brass infill joint, although proving faster results, fails due to increased frictional forces within the assembly. Since the standard atmospheric temperatures do not sore up to 750 – 850 C, Fresnel sheet lenses are used in the apparatus to concentrate the solar energy and passively actuate the system of joints. The resultant 2-Dimensional displacement of Nitinol joints is coupled with the 3-Dimensional tessellation to produce a deployable unit which can be customized to suit different design applications.
Passive Investigation 1.0 involves the use of multiple concentric Fresnel to focus the solar radiations on Nitinol to activate the kinetic joints. Passive Investigation 2.0 involves quick simulation of a linear Fresnel lens by moving the focal point of concentric Fresnel lens along the total length of the Nitinol spring. The results prove the performance of the kinetic Nitinol joints in a complete passive condition.
The Nitinol spring needs to be heated on every point along its length to achieve a 100% contraction. Due to the commercial unavailability of linear Fresnel lenses, multiple concentric lenses are used in this project to simulate similar behaviour. It however restricts the full contraction of the kinetic Nitinol joints. This limitation can be overcome with production of linear Fresnel lenses, with a focal length designed to suit the customised needs of the system for optimum efficiency.
The prototype consists of 16 kinetic Nitinol joints with Nitinol springs of 2cm each, forming 4 clusters of joints, collectively synchronizing to mobilize the model. The joints are embedded in a folding geometry which not only expands the volume but also its surface area. Apart from its advantage of being light weight, construction in a fabric enclosure has been intentionally chosen to transfer the loads uniformly and minimise the need of additional joineries.
The prototype is a part model of a larger concept which the team visualizes to be a stand-alone single person shell which can be transported and deployed on leisure sites, like camps or beaches. Or it can resort as day-light shelters in the deserts with extreme climate. The team envisions the project to open possibilities for adaptive architecture which is inexpensive in construction, lightweight, and transforms the interior spaces according to the relative position of sun.
As an alternative on a smaller scale, the team proposes the use of this system to function as a completely passive, responsive building skin or roof. Where, in the presence of sun, when the interior temperature is above the comfort zone, the expansion joints would release the forces to expand and exhale the accumulated hot air through the perforated side panels. This process would reverse in absence of sun or in cloud cover as the comfort temperature would be attained thus giving it breathing and exhaling quality. Solar fabric panels could be attached to the geometry to capture and store energy from sun as the surface area increases on actuation, creating a self-sustaining model for smart cities. Experimentally, this system could also be adaptable in fashion industry to produces heat responsive garments.
There is a need to make our buildings function in harmony with the environment, however, simply making technology increasingly efficient towards zero-energy state, is not the solution. We have to find ways to integrate material properties into architecture and the Self-adaptive Membrane attempts to make an initiation in this passive intelligence. The ultimate aim of the project is not only to design an architectural prototype which adapts to different environments for controlled cooling and lighting, but to propose the possibility of using this passive system of joints into variety of design applications to shape a sustainable future.