A research team from the University of Michigan – Shanghai Jiao Tong University Joint Institute (UM-SJTU JI, JI hereafter) has published an article titled “Thermal Computing with Mechanical Transistors” in Advanced Functional Materials, a top-tier materials science journal with a Nature Index Impact Factor of 19. Featured on the inside cover of the journal, the article highlighted mechanical transistors developed by the research team and demonstrated thermal computing to supplement traditional electronic computing, which faces challenges such as high-power consumption, security vulnerabilities, and susceptibility to extreme environmental conditions like intense heat and radiation.

Led by two JI professors, Jaehyung Ju and Lei Shao, the team designed a multifunctional mechanical transistor equipped with a Kirigami thermomechanical sensor and a bistable actuator. This innovation enables in-memory computing for both combinational and sequential logic. The approach utilizes modular construction, symmetry breaking, and nonlinear materials to create logic gates and memory units that respond to environmental stimuli through thermal delay.

Journal cover page featuring JI team research

The research project was initiated by master student Chao Song and Professor Ju  in 2020. After Song left JI for his further study, doctoral student Huyue Chen and Professor Shao joined the project. The team later invited other JI faculty members, including Professor Zhaoguang Wang (Thermal Engineering), Professor Yuljae Cho (Logic Gate Design), and Professor An Zou (Electronic Circuit Design), to collaborate.


JI team research diagrams on mechanical transistor

Speaking of the interdisciplinary achievement encompassing solid mechanics, thermal engineering, materials science and engineering, computer science, electrical engineering, and systems engineering, Professor Ju said: “JI offers a unique working environment that fosters collaboration among faculty with diverse technical backgrounds. We can leverage these benefits by staying humble and open to each other’s ideas to create a dynamically collaborative working environment at JI.”

Author Team Introduction

Huyue Chen is a Ph.D. candidate of the UM-SJTU Joint Institute. As a guest researcher, he joined Prof. Metin Sitti’s group in Max Planck Institute for Intelligent Systems and Koc University. His research interests cover physical intelligence, mechanical metamaterials, and biomedical micro-robotics.
Chao Song received a master’s degree from the UM-SJTU Joint Institute in 2021. He is now in a Ph.D. program in Westlake University. His research focuses on the mechanics and design of mechanical metamaterials.
Lei Shao is an associate professor at the UM-SJTU Joint Institute. He received his Ph.D. degree in mechanical engineering from University of Michigan, Ann Arbor in 2014. Then, he was a postdoc research fellow at National Institute of Standards and Technology, USA till 2018. His research interests include dynamics, vibrations and control of micro-electromechanical systems (MEMS).
Jaehyung Ju is an associate professor at UM-SJTU Joint Institute. He received his Ph.D. degree in mechanical engineering from Texas A&M University in 2005, and was a postdoc research associate at Texas A&M University and Clemson University from 2005 to 2011. In 2023, he became an ASME Fellow. His research topics are the mechanics and design of mechanical metamaterials.