<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>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/17140397 |
| Date | 20 December 2021 |
| Creators | Wan kyn Chan (11807537) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/Mechxels_Leveraging_Bistable_Structures_for_Color_Change_Character_and_Image_Display/17140397 |
Page generated in 0.0023 seconds