The self-adaptive membrane project uses shape memory alloy nitinol to create a passive kinetic system of joints and a folding geometry. When solar radiation heats the nitinol above a threshold, it contracts and causes the geometry to deploy, expanding the surface area and volume. Tests showed the kinetic joints perform loop displacements in response to solar heating without external energy. The team envisions applications like portable shelters or building skins that breathe by expanding and contracting based on interior temperature. The goal is to integrate passive material properties into architecture for controlled lighting and cooling without energy inputs.

1. SELF-ADAPTIVE MEMBRANE
Digital Matter – Intelligent Constructions
Prologue
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 or
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, this
practise has set itself apart on a new path, further away from the passive traditional solutions in
architecture, thus creating an ever increasing gap.
Project introduction
‘Self-adaptive Membrane’ is a research and built project developed at the Institute for Advanced
Architecture of Catalonia, Spain by Master research students 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, made up of Nickle and Titanium, to develop a passive kinetic motor which is capable of
deploying geometries in response to the presence of solar radiation.
Project description
‘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.
Nitinol is a smart material which possesses the ability to transform back to its original shape
(Austenite state) at an actuation temperature which ranges from 750
- 85o
C. Although commercial
springs have a high actuation temperature, unachievable in standard climatic conditions, they
possess a larger amount of strength. A Nitinol commercial spring has the ability to pull up to forces
of 16N per 20mm of length of spring. This property of transforming with high strength is used to
find the balance of forces to design a kinetic Nitinol joint. 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 kinetic Nitinol joints perform a loop displacement motion in presence
and absence of solar radiation thus creating an independent mobile mechanism. Since the standard
atmospheric temperatures do not sore upto750
- 85o
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-Dimentional tessellation to
produce a deployable unit which can be customized to suit different design applications.
Design prototype (electrical stimuli due to the unavailability of linear lenses)
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.
Passive Tests
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

2. total length of the Nitinol spring. The results prove the performance of the kinetic Nitinol joints in a
complete passive condition.
Limitations
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 need of the system for optimum efficiency.
Design ideology
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 transform 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 geometry would expand to 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 of smart
cities.
Conclusion
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
building applications to shape a sustainable future.
Courtesy Institute for Advanced architecture of Catalonia, Spain.
Senior Faculty
Areti Markopoulou
Assistant Faculty
Alexandre Dubor
Computational Expert
Carlos Bausa
Team
Nohelia Gonzalez
Shreyas More