Seminar with scholars from Seoul National University

Event interval: Single day event
Campus location: Bill & Melinda Gates Center for Computer Science & Engineering (CSE2)
Campus room: 371
Accessibility Contact: aafrontdesk@uw.edu
Event Types: Lectures/Seminars

We have two great speakers, both PhD candidates in mechanical engineering from Seoul National University!

1. Youngkwon “YK” Kim
Modular Reconfigurability for Auxiliary Attitude Control

Abstract
The evolution of spaceborne structures is increasingly driven by modular design principles that enable adaptable, scalable, and multifunctional operational capabilities. From deployable arrays to robotic servicing platforms, such modularity is redefining how spacecraft adapt to evolving mission requirements. In this work, we investigate how structural metamorphism within multifunctional modular assemblies can be exploited as an auxiliary attitude-control mechanism for spacecraft. We consider a reconfigurable modular chain–spacecraft assembly in which the modular units can fold, deploy, and reorient relative to one another, thereby altering the overall configuration and tuning the spacecraft’s inertia properties through internal momentum exchange.

 To evaluate the resulting attitude-control capability, we develop a three-dimensional multibody dynamics simulation framework that models reconfigurable modular assemblies attached to a base spacecraft hub under free-floating conditions. Numerical results show that appropriately designed reconfiguration sequences of the modular units can generate desired counter-translations and rotations of the base hub. We demonstrate that the achievable attitude-control maneuvers are strongly influenced by both the sequence and the combination of modular reconfigurations. Moreover, navigating alternate morphing paths to the same final configuration yields distinct inertia-evolution trajectories, each imparting a unique influence on the spacecraft orientation. We further investigate the influence of inter-module connectivity on the attainable attitude-control range, highlighting the potential of reconfigurable modular structures to serve as an auxiliary attitude-control system and to support extended operational lifetimes for advanced space missions.

Bio :
Youngkwon “YK” Kim is a second-year Ph.D. candidate in Mechanical Engineering at Seoul National University, working with Prof. Jinkyu Yang (formerly in the Department of Aeronautics & Astronautics at the University of Washington, 8/2013–9/2022). His research focuses on shape-morphing and transformative structures for space systems and wearable devices. Parts of this work will also be presented at the AIAA (American Institute of Aeronautics and Astronautics) SciTech 2026 Forum. YK is passionate about sharing knowledge and supporting students’ growth: he has written a book on effective learning in university (“How Can We Study Effectively in the University System? – Key Factor: Proactive Questions”) and serves as the head of the department’s largest community (about 640 students) in the Department of Mechanical Engineering at Inha University. He also actively collaborates with international research groups at the University of Washington (USA), BITS Pilani (India), and KAIST (Korea).

2. Myeonggyun Joo
Expandability of Simple Linkage: Localization and Topology

Abstract: In this talk, I will introduce an asymmetric linkage system that is structurally simple yet exhibits remarkably unique behavior. Inspired by natural mechanisms, this system consists of two slanted bars connected by a rail and a torsional spring. Depending on where the torsional spring is placed—at the top hinge or the bottom hinge—the system can be modeled in two distinct ways.
Modeling 1 places the torsional spring at the top hinge and is more straightforward to analyze. Using mathematical techniques, the system matrix can be simplified, enabling eigen analysis that reveals the presence of edge modes. By tuning geometric parameters, this model demonstrates an extremely localized phenomenon known as the Singular Edge Mode, in which only the first unit cell oscillates.
Modeling 2 places the torsional spring at the bottom hinge and exhibits a more robust form of edge localization. Due to the system’s inherent asymmetry, this configuration has nontrivial topological characteristics. Regardless of where the system is excited, the edge cell consistently shows accumulated localized behavior, serving as evidence of a Topological Edge Mode.
Because of its simplicity, tunability, and the richness of its edge phenomena, this asymmetric linkage system offers strong potential for applications in various mechanical and metamaterial design contexts.

Bio :
Myeonggyun Joo is a second-year Ph.D. candidate in Mechanical Engineering at Seoul National University, working under the supervision of Prof. Jinkyu Yang (formerly in the Department of Aeronautics & Astronautics at the University of Washington, 2013–2022). His research focuses on wave dynamics, topological mechanical metamaterials, and the design and fabrication of architected structures. Portions of this work were presented at the PHONONICS 2025 conference. Publications on this topic are currently in preparation in collaboration with international research groups at IIS (India) and CNRS (France). He aims to uncover new physical mechanisms in mechanical systems that enable programmable dynamics and multifunctional responses. He is also deeply interested in cross-disciplinary collaborations that bridge metamaterials with fields such as robotics and aerospace engineering.