Spelling suggestions: "subject:"morphine structures""
1 |
Mechxels: Leveraging Bistable Structures for Color Change, Character, and Image DisplayWan kyn Chan (11807537) 20 December 2021 (has links)
<p>A key aspect of color change is
altering perceived value or intensity. This dissertation presents a methodology
to achieve value change through mechanical means via the deflection of bistable
structures. We create the Mechxel, two methods of mechanical pixel-based,
reversible color change using 3D printed switchable multistability and bistable
switch panels that augment the projected area a viewer perceives which enables
the creation of image and character tessellation.</p>
<p>Switchable multistability (SMS)
arises from the combination of pre-strain and shape memory, allowing us to
access multiple elastically programmed shapes at elevated temperatures with
fast morphing and low actuation forces, while retaining high stiffness at room
temperature. We design and manufacture SMS Mechxels using fused deposition
modeling (FDM) 3D printing on the Ultimaker 3D printer in a bilayer layup of
polylactic acid (PLA) with a [90/0] print direction while iteratively
miniaturizing the physical size to enhance the resolution while also reducing
the size of the overall tessellated display. Leveraging SMS properties
programmed into each Mechxel, the projected area to a viewer will vary between
the unit’s stable states, creating a difference in perceived value of coloration
due to changes in area. To ease the tessellation process, we also introduce a
tessellation user interface that maps images to their tessellated equivalent to
reduce tessellation trial and error. This interface also calculates the number
of Mechxels required in their respective states and the final physical size of
the display. We then carry out image processing to justify this change in value
between stable states and run preliminary optical character recognition.</p>
<p>Inspired by mechanical bistable
mechanisms, the bistable switch Mechxels utilize changes in a surface’s
projected area to a viewer via changes in the angle of a bistable tile using a 5-by-5
grid for character replication and display. Comprising of three main components
– two bistable switches, a colored tile and a base, design considerations were
made to create an easy to assemble and replaceable 3D printed grid system that
could be interacted with by audiences or easily electromechanically actuated. Using
pixel-by-pixel comparisons and Sorensen-Dice coefficient, characters using the
typeface Silkscreen were documented on these tiled grids yielding high
similarity and low error when compared to their digital reference images in
various positions and orientations. We also experiment with transitional waves
as a promising means of actuation to change the Mechxel between their stable
states.</p>
<p>The Mechxels considered in this
research introduce a new means of purely mechanical color change, character,
and image display either leveraging the elastic properties of shape memory
polymers (SMPs) or bistable mechanisms. With potential applications in passive
morphing architecture, adaptive camouflage, and interactive aesthetic, Mechxels
opens the door to limitless design possibilities through a new perspective into
color change.</p>
|
2 |
Use of Piezoelectric Actuators to Effect Snap-Through Behavior of Unsymmetric Composite LaminatesSchultz, Marc Robert 23 April 2003 (has links)
As a new concept for morphing structures, the use of piezoelectric actuators to effect snap-through behavior of simple unsymmetric cross-ply composite laminates is examined. Many unsymmetric laminates have more than one stable room-temperature shape and can be snapped through from one stable shape to another. In this new concept for morphing structures, one or more piezoelectric actuators are bonded to unsymmetric laminates, and are then used to snap the laminate from one shape to another. The actuator would be used to change shape, but would not be required to maintain the shape. Using the Rayleigh-Ritz technique, several models are developed to predict the interaction between the base laminate and the actuator. In particular, the voltage (applied to the actuator) needed to snap the laminate is predicted. The NASA-LaRC Macro-Fiber Composite&174; (MFC&174;) actuator is chosen as the actuator of choice for this work. A laminate is manufactured, an actuator is bonded to the laminate, and experiments are performed. Since the agreement between the initial models and experimental results was not good, the models were revised. Good agreement between the predictions of the revised model and experiment is reached. Suggestions for future research directions are presented. / Ph. D.
|
3 |
Genetic optimization and experimental validation of a camber morphing winglet / Estudo da aplicação de uma winglet de camber variável em um jato executivoEguea, João Paulo 18 March 2019 (has links)
International aviation regulations on emissions are becoming more strict. Improvements goals on fuel efficiency demand development of technologies capable of reducing fuel consumption and gas emissions. Morphing structures capability to adapt their aerodynamic shape for optimal condition in flight brings potential for reduction of aircraft drag and operating fuel consumption, minimizing gas emissions and fuel expenses. This study presents an investigation on the impact of a camber morphing winglet on midsize business jet using numerical simulation and wind tunnel experiments. A genetic algorithm was used to optimize the winglet sections camber for different flight conditions. Optimized geometries achieved total drag reduction of up to 0.58% compared to original winglet for single condition optimization, reaching up to 7 % reduction on consumed fuel on a typical mission. This efficiency improvement allows aircraft to carry 900 kg additional load, comprising the morphing system and extra payload. There is an indication of even better results for applications on a bigger commercial jet. Presented methodology is also suitable for new winglet fixed geometry design or incorporating morphing technology. Aerodynamic balance force measurements showed that optimized winglets increased the wing effective aspect ratio (AReff), reducing the lift-induced drag, and maximum lift coefficient (CLmax). However, maximum lift to drag ratio (L/Dmax) was reduced on CL optimization region due to flow differences between optimization and wind tunnel conditions. Aerodynamic efficiency improvement was found for greater lift coefficients (CL). Reductions on wing tip vortex size and intensity due to winglet installation are seen on measured vorticity map, showing liftinduced drag reduction according to Maskells equation. Parabolic drag polar and Maskells equation methods were used for lift-induced drag calculation, using balance force and flowing mapping data for calculations. The presented concept showed considerable aircraft performance improvement, using a feasible device with greater certification ease than other morphing structures concepts, once the failure of this system would not compromise flight safety. Further investigation using computational fluid dynamics (CFD) and wind tunnel experiments is necessary to develop and test a functional camber morphing winglet device. / Regulamentações internacionais sobre emissões estão se tornando mais rigorosas. Metas de melhoria da eficiência de consumo de combustível demandam o desenvolvimento de tecnologias capazes de reduzir o consumo e emissões de gases. Estruturas capazes de adaptar sua forma aerodinâmica para condição ótima em voo trazem potencial de redução do arrasto e consumo de combustível da aeronave, minimizando as emissões de gases e gastos com combustível. Este estudo apresenta uma investigação sobre o impacto de uma winglet de camber variável em um jato executivo da categoria mid size utilizando simulação numérica e experimentos em túnel de vento. Um algoritmo genético foi usado para otimizar o camber das seções para diferentes fases de voo. As geometrias otimizadas reduziram o arrasto total em até 0.58% comparadas a winglet original na otimização de condição única, alcançando até 7% de redução no combustível consumido em missão típica. Essa melhoria de eficiência permite a aeronave carregar 900 kg de carga adicional, composta pelo sistema de adaptação e carga paga extra. Há uma indicação de resultados ainda melhores para aplicação em um jato comercial maior. A metodologia apresentada é apropriada para projeto de uma nova winglet de geometria fixa ou que incorpore a tecnologia de adaptação. Medidas de força com balança aerodinâmica mostraram que as winglets otimizadas aumentaram o alongamento efetivo da asa (AReff), reduzindo o arrasto induzido, e o coeficiente de sustentação máximo (CLmax). No entanto, a máxima razão entre sustentação e arrasto (L/Dmax) foi reduzida dentro do intervalo de CL da otimização devido as diferenças entre as condições do escoamento na otimização e no túnel de vento. Melhoria na eficiência aerodinâmica foi obtida para coeficientes de sustentação (CL) maiores. Reduções no tamanho e intensidade do vórtice de ponta de asa são vistas nos mapas de vorticidade medidos, mostrando redução do arrasto induzido segundo a equação de Maskell. Os métodos da polar de arrasto parabólica e da equação de Maskell foram usados para o cálculo do arrasto induzido, utilizando nos cálculos os dados de força da balança e o mapeamento do escoamento. O conceito apresentado mostrou melhoria considerável no desempenho da aeronave, utilizando um sistema factível e com maior facilidade para certificação que outros conceitos de estruturas adaptáveis, uma vez que a falha desse sistema não comprometeria a segurança do voo. Mais estudos são necessários para desenvolver e testar uma winglet de camber varável funcional.
|
4 |
Modeling of Microvascular Shape Memory CompositesTerzak, John Charles January 2013 (has links)
No description available.
|
Page generated in 0.0797 seconds