The engineering world has exploded with recent interest in the craft of origami. This traditional art form most often associated with Japan has become fertile ground for inspiration of devices with applications ranging from medicine to aerospace. What is it about origami that makes it attractive, and why is the origami revolution occurring now? This talk will present an overview of the prominent figures and applications that are currently driving innovation in the field. Engineers and artists alike have come together to develop new techniques that take the practice from paper curiosities to practical engineered devices and systems. Foldable tools are now entering the human body during minimally invasive surgery, and foldable optical structures are being designed for the next generation of space-based telescopes. Mathematicians, material scientists, roboticists, architects, and mechanical designers are all investigating classical origami patterns and inventing new ones, benefiting from the insights and craftsmanship of partnering artist. The resulting software tools are accessible by engineers, tinkerers, and artists alike, some of who then leverage laminated manufacturing techniques to fabricate fully operational systems with embedded electrical components and smart material actuation. While engineering is often influenced by external disciplines, such as biology or aesthetics, the melding of engineering and origami has been uniquely synergistic. The interaction of scientists and artists has mutually benefited both sides: beyond the novel advancements in engineering, the artists themselves are taking back the numerical tools and material innovations, using them to produce revolutionary pieces of balanced complexity and elegance.
An external occulter for starlight suppression – a starshade – flying in formation with the Habitable Exoplanet Imaging Mission Concept (HabEx) space telescope could enable the direct imaging and spectrographic characterization of Earthlike exoplanets in the habitable zone. This starshade is flown between the telescope and the star, and suppresses stellar light sufficiently to allow the imaging of the faint reflected light of the planet. This paper presents a mechanical architecture for this occulter, which must stow in a 5 m-diameter launch fairing and then deploy to about a 80 m-diameter structure. The optical performance of the starshade requires that the edge profile is accurate and stable. The stowage and deployment of the starshade to meet these requirements present unique challenges that are addressed in this proposed architecture. The mechanical architecture consists of a number of petals attached to a deployable perimeter truss, which is connected to central hub using tensioned spokes. The petals are furled around the stowed perimeter truss for launch. Herein is described a mechanical design solution that supports an 80 m-class starshade for flight as part of HabEx.
HanaFlex is a new method for deployment from a compact folded form to a large array derived from the origami flasher folding pattern. One of the unique features of this model is that the height constraints of the stowed array do not limit the deployed diameter. Additional rings can be added to increase the deployed diameter while only minimally increasing the stowed diameter. Larger solar arrays may enable longer missions in space, manned missions to distant destinations, or clean energy sources for Earth. The novel folding design of the HanaFlex array introduces many new possibilities for space exploration. This paper demonstrates the performance of the HanaFlex array in four areas: deployed stiffness, deployed strength, stowed volume specific power, and mass specific power.
The flow fields and boundary erosion that are associated with scour at bridge piers are very complex. Direct
measurement of the boundary shear stress and boundary pressure fluctuations in experimental scour research has always
been a challenge and high spatial resolution and fidelity have been almost impossible. Most researchers have applied an
indirect process to determine shear stress using precise measured velocity profiles. Laser Doppler Anemometry and
Particle Image Velocimetry are common techniques used to accurately measure velocity profiles. These methods are
based on theoretical assumptions to estimate boundary shear stress. In addition, available turbulence models cannot very
well account for the effect of bed roughness which is fundamentally important for any CFD simulation. The authors have
taken on the challenge to advance the magnitude level to which direct measurements of the shear stress in water flow can
be performed. This paper covered the challenges and the efforts to develop a higher accuracy and small spatial resolution
sensor. Also, preliminary sensor designs and test results are presented.
We present a framework for the design of a compliant <i>system</i>; i.e. the concurrent design of a compliant mechanism with
embedded actuators and embedded sensors. Our methods <i>simultaneously</i> synthesize optimal structural topology and
placement of actuators and sensors for maximum energy efficiency and adaptive performance, while satisfying various
weight and performance constraints. The goal of this research is to lay an algorithmic framework for distributed
actuation and sensing within a compliant active structure.
Key features of the methodology include (1) the simultaneous optimization of the location, orientation, and size of
actuators <i>concurrent</i> with the compliant transmission topology and (2) the concepts of controllability and observability
that arise from the consideration of control, and their implementation in compliant systems design. The methods used
include genetic algorithms, graph searches for connectivity, and multiple load cases implemented with linear finite
element analysis. Actuators, modeled as both force generators and structural compliant elements, are included as
topology variables in the optimization. Results are provided for several studies, including: (1) concurrent actuator
placement and topology design for a compliant amplifier and (2) a shape-morphing aircraft wing demonstration with
three controlled output nodes. Central to this method is the concept of structural orthogonality, which refers to the
unique system response for each actuator it contains. Finally, the results from the <i>controllability</i> problem are used to
motivate and describe the analogous extension to <i>observability</i> for sensing.