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Dissertation Thesis Panels


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Panels presented at Architectural Association Dissertations Review Jury for Msc candidatures, Sep 09

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Dissertation Thesis Panels

  1. 1. Biomimetics Fibre organisation strategies in nature Biology makes use of remarkably few materials and nearly all loads are carried by fibrous composites. There are only four types of fibers: cellulose in plants, collagen in animals, chitin in insects and crustaceans and silks in spider webs. These are the basic materi- als of biology and they have much lower densities than most engineering materials. They are success- ful not so much of what they are but because the way in which they are put together. Thigmo-Morphogenesis Thigmo-morphogenesis, refers to the changes in shape, structure and material properties that are pro- duced in response to transient changes in environ- mental conditions. This property can be observed in the movement of sunflowers, bone structure and sea urchins.These are all growth movements or slow adaptations to changes in specific conditions that occur due to the nature of the material, which are essentially fibrous tissue. Morpho-Mechanical Computation One of the most interesting aspects of mul- tifunctionality and integration in biology is the way in which receptors detect and am- plify mechanical strains and displacements through mechano-receptors. They do exist in all creatures, plants and animals. These receptors function as mechanical signal am- plifiers of strain concentrations caused by changes in the environment. The energy input or stimulus from the en- vironment is picked up by the mechanore- ceptors which transduce them into electric signals. The electrical signals acts as the ba- sic information which is further processed by the nervous system in case of higher lev- el organisms while in lower level organisms, the signals are used for sequential actua- tion through altering the material organiza- tion. The responsive behaviour or adaptive growth in natural organisms emerge as a re- sultant of a complex process of sensing, in- formation processing, control and actuation. Energy Input (Stimulus) Device (Transduction) Electrical Signal Filtering Processing Response Behaviour Actuator Systems Controlled Structures Smart Structures Smart Adaptive Structures Intelligent Adaptive Structures Self- learning Reactive Structures Self- learning Smart Structures Structures Neural Network Systems Sensor Systems Fibre Organisation Strategies Morpho-Mechanical Computation Thigmo-Morphogenesis Precedents s ense a ctuate e nergy c ontrol s a ec s a e s a e c Hypo-surface Cartesian- Wax Smart Plane s a e c s a e Responsive Systems in Nature Lower-level Organisms Higher-level Organisms Biomimetics Research MSc Dissertation Maria Mingallon, Konstantinos Karatzas, Sakthivel Ramaswamy Emergent Technologies and Design Programme 2008-09
  2. 2. Base Material_Fibre Composite In its most basic form a composite material is one which is composed of at least two elements working together to produce material properties that are different to the properties of those elements on their own The greatest advantage of composite materials is strength and stiffness combined with lightness. By choosing an appropriate combination of reinforcement and matrix material, we produce properties that exactly fit the requirements of a particular structure or purpose. Another advantage of composite materials is that they provide design flexibility -They can be moulded into complex shapes. Sensing Fibre Optics An optical fibre is a glass or plastic fibre that carries light along its length. Light is kept in the core of the optical fibre by total internal reflection. Widely used in fibre-optic communications, which permits transmission over longer distances and at higher bandwidths (data rates) than other forms of communications Fibre Optic Sensors Canmeasurestrain,temperature,pressure,viscosity, water vapour content, and other by modifying a fibre so that the quantity to be measured modulates the intensity, phase, polarization, wavelength or transit time of light in the fibre. Thermocouples A thermocouple is a junction between two different metals that produces a voltage related to a temperature difference. Widely used type of temperature sensor Strain Gauges A device used to measure the strain of an object. Thegaugeisattachedtotheobjectandastheobject is deformed, the foil deforms, causing its electrical resistance to change. This resistance change is related to the strain by the quantity known as the gauge factor. Actuation A shape memory alloy (SMA) is an alloy that “remembers” its shape, and can be returned to that shape after being deformed, by applying heat. SMAs have the highest known force/weight ratio among actuators Shape Setting TheNi-Tiribbonandwiresweretrainedbyrolling them around metal pipes and maintaining them in position while they were placed in an oven. The oven was heated upto 500°C and the temperature was maintained for 5 minutes. The SMAs were subsequently removed from the oven and immediately immersed in cold water whilst maintaining the imposed bend shape throughout the cooling procedure. Actuation Experiments - Weight lifting These set of experiments were focused on extrapolating the Force to Weight ratio and Force-Time graph. It was observed that the SMA ribbon of 9 gm in a cantilevered position could lift load up to 114 gm.The load carrying capacity of the SMA ribbon improved significantly when the strip was simply supported. The ribbon of 9 gm could lift a load of 883 gm, almost 100 times it self-weight. Actuated Canopy A smart fibre composite, with embedded SMAs could allow the strip morphology of the canopy todynamicallyreorganise,openandclosebased on current environmental conditions. Actuated Openings The SMA wires were cut and bundled together forming arcs. A bundle of three fibres was woven to the felt to create openings. As they were heated the surface opens of both on the inside and outside. Actuation + Control Experiments In the second Phase of our actuation experiments, we added the factor of control in the actuation process. The temperature of the SMA ribbons was monitored, and the system actuated accordingly. Sensing Experiments Strain Gauges were used to sense the strain, on a piece of fibre-reinforced polyester resin. The strain gauges processing unit was calibrated accordingly and the sensing system was prepared to be linked with the actuation system and integrated in the final model. Sensing + Actuation + Control Thefinalmodel(below)isaGlassFibreReinforced EpoxyResinSandwichStructurewithembedded SMAs (4 Ribbons) and Thermocouples. Two Strain Gauges are attached on the surface. When the Strain Gauges sense strain, the give a signal to their processing unit. Sequentially, an output of 0-2Volts is generated and acts as an input for another controller that switches on or off the actuation circuit. 40 degrees 30 degrees 53 degrees 65 degrees Technology + Experiments MSc Dissertation Maria Mingallon, Konstantinos Karatzas, Sakthivel Ramaswamy Emergent Technologies and Design Programme 2008-09
  3. 3. Geometry In structural design, traditional methods tend to group structural elements in accordance with the type of external loads they would have to withstand during their life time. Our aim has been to develop a material system ca- pable of withstanding a wide spectrum of loading conditions by adapting its structural capacity when and where required. This adaptation occurs via both the global and local geometry. Stiffness differentation in the global geometry is achieved through the manipulation of two factors: overall form derived through digital form finding and fibre organisation based on the analysis of prin- cipal stresses. Fuzzy Logic Multi-valued logic derived from fuzzy set theory to deal with rea- soning that is approximate rather than precise. Actuation Logic Actuator positioned along su- ture curve’ enhances the system through dynamic adaptation. Space Truss from Interwoven Continuous Surface Topology Local Geometry Global Geometry Global Geometry Screen Walls by Erwin Hauer; Installation in showroom of Knoll Internacional de Mexico, Mexico City 0 1 Two Hexagonal Grids Layers Connectivity - Tripods Tripods frame Suture Curves Material Hierarchies Concept Space Truss Space Truss Openning Suture Curves Grids Distorsion Grids Spacing Variables Curvature Height a h Continuous Surface Space Truss Fibre Distribution Shape Memory Alloy Actuation Sensing Material Fibre Optic Structural Fibres a a’ s m a m s a e a a’ Geometry_01 MSc Dissertation Maria Mingallon, Konstantinos Karatzas, Sakthivel Ramaswamy Emergent Technologies and Design Programme 2008-09