宇宙科学広報・普及主幹付

Hiromi Yasuda

  (安田 博実)

Profile Information

Affiliation
Assistant Professor, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency
Degree
Ph.D.(Mar, 2018, University of Washington)

Researcher number
10910903
ORCID ID
 https://orcid.org/0000-0002-7296-0305
J-GLOBAL ID
202301015829516999
researchmap Member ID
R000057573

Papers

 32
  • Hiromi Yasuda, Takahiro Kunimine
    MRS Communications, Jan 31, 2024  
  • Koshiro Yamaguchi, Yasuhiro Miyazawa, Hiromi Yasuda, Yuyang Song, Shinnosuke Shimokawa, Umesh Gandhi, Jinkyu Yang
    Materials and Design, 233, Sep, 2023  
    We investigate the reconfigurability and tunability of the tessellation of Tachi-Miura Polyhedron (TMP), an origami-based cellular structure composed of bellows-like unit cells. Lattice-based three-dimensional mechanical metamaterials have recently received significant scientific interest due to their superior and unique mechanical performance compared to conventional materials. However, it is often challenging to achieve tunability and reconfigurability from these metamaterials, since their geometry and functionality tend to be pre-determined in the design and fabrication stage. Here, we utilize TMP's highly versatile phase-transforming and tessellating capabilities to design reconfigurable metamaterial architecture with tunable mechanical properties. The theoretical analyses and experiments with heat processing discover the wide range of the in-situ tunability of the metamaterial – specifically orders of magnitude change in effective density, Young's modulus, and Poisson's ratio – after its fabrication within the elastic deformation regime. We also witness a rather unique behavior of the inverse correlation between effective density and stiffness. This mechanical platform paves the way to design the metamaterial that can actively adapt to various external environments.
  • H. Yasuda, H. Shu, W. Jiao, V. Tournat, J. R. Raney
    Applied Physics Letters, Jul 31, 2023  
  • Yasuhiro Miyazawa, Hiromi Yasuda, Jinkyu Yang
    Acta Mechanica Sinica/Lixue Xuebao, 39(7), Jul, 2023  
    As an art of paper folding, origami has been widely explored by artists for centuries. Only in recent decades has it gained attention from mathematicians and engineers for its complex geometry and rich mechanical properties. The surge of origami-inspired metamaterials has opened a new window for designing materials and structures. Typically, to build origami structures, a sheet of material is folded according to the creaselines that are marked with compliant mechanisms. However, despite their importance in origami fabrication, such compliant mechanisms have been relatively unexplored in the setting of origami metamaterials. In this study, we explore the relationship between the design parameters of compliant mechanisms and origami mechanical properties. In particular, we employ single hinge crease and Kresling origami, representative examples of rigid and non-rigid origami units, fabricated using a double-stitch perforation compliant mechanism design. We conduct axial compression tests using different crease parameters and fit the result into the bar-hinge origami model consisting of axial and torsional springs. We extract the relationship between the spring coefficients and crease parameters using Gaussian process regression. Our result shows that the change in the crease parameter contributes significantly to each spring element in a very different manner, which suggests the fine tunability of the compliant mechanisms depending on the mode of deformation. In particular, the spring stiffness varies with the crease parameter differently for rigid and non-rigid origami, even when the same crease parameter is tuned. Furthermore, we report that the qualitative static response of the Kresling origami can be tuned between monostable and bistable, or linear and nonlinear, by only changing the crease parameter while keeping the same fold pattern geometry. We believe that our compiled result proffers a library and guidelines for choosing compliant mechanisms for the creases of origami mechanical metamaterials.[Figure not available: see fulltext.]
  • Hiromi Yasuda, Jinkyu Yang
    Lecture Notes in Civil Engineering, 254 LNCE 409-416, 2023  
    It is crucial to monitor the wingtip deflection of aircraft in real-time to ensure its aerodynamic functionality and structural safety. Also, the prediction of the wing tip deflection can be highly useful to provide aircraft with improved maneuverability and agile response to sudden events, such as gust and flutter. In this study, we propose a wingtip deflection monitoring/prediction method based on machine learning techniques. Specifically, we employ an aerodynamic solver to simulate an aeroelastic flutter behavior of a fixed-wing, and demonstrate the feasibility of our approach to predict oscillatory wingtip motion due to the flutter. To track and predict the wingtip deflection, we build network architectures composed of convolutional neural networks (CNNs) to analyze optically measured data and recurrent neural networks (RNNs) to process time-series information. As a result, we find the proposed technique is capable of monitoring and predicting wingtip deflection in an accurate and efficient manner. We expect this vision and machine-learning-based technique can complement existing sensor technologies to enhance the safety and maneuverability of aircraft.

Misc.

 1
  • Hiromi Yasuda, Philip R. Buskohl, Andrew Gillman, Todd D. Murphey, Susan Stepney, Richard A. Vaia, Jordan R. Raney
    Nature, 598(7879) 39-48, Oct 7, 2021  
    Mechanical mechanisms have been used to process information for millennia, with famous examples ranging from the Antikythera mechanism of the Ancient Greeks to the analytical machines of Charles Babbage. More recently, electronic forms of computation and information processing have overtaken these mechanical forms, owing to better potential for miniaturization and integration. However, several unconventional computing approaches have recently been introduced, which blend ideas of information processing, materials science and robotics. This has raised the possibility of new mechanical computing systems that augment traditional electronic computing by interacting with and adapting to their environment. Here we discuss the use of mechanical mechanisms, and associated nonlinearities, as a means of processing information, with a view towards a framework in which adaptable materials and structures act as a distributed information processing network, even enabling information processing to be viewed as a material property, alongside traditional material properties such as strength and stiffness. We focus on approaches to abstract digital logic in mechanical systems, discuss how these systems differ from traditional electronic computing, and highlight the challenges and opportunities that they present.

Research Projects

 5