Dr. Motohisa Hirano, Professor, Department of Mechanical Engineering, Faculty of Science and Engineering, Hosei University, Japan

Biography: Dr. Motohisa Hirano is currently Professor at the Department of Mechanical Engineering, Faculty of Science and Engineering, Hosei University, Japan. He has studied the atomistics of friction and superlubricity: a state of vanishing friction. Following his graduation from the Graduate School of Engineering, Nagoya University, in 1982, he joined Nippon Telegraph and Telephone Public Corporation in the same year. After working for Nippon Telegraph and Telephone Corporation and serving as a professor at the Faculty of Engineering, Gifu University, he has been serving as a professor at Hosei University, since 2014. He obtained a doctoral degree in engineering in 1989, from Nagoya University, and in science in 1998, from the University of Tokyo. Professor Hirano has authored over 200 scientific publications on engineering and science on the atomistics of friction and nanotribology. Laboratory HP: http://hirano-lab.ws.hosei.ac.jp/index_j.html

Speech Title: Non-Linear Dynamical Effects in Frictional Energy Dissipation

Abstract: The non-linear dynamics in friction is studied from an atomistic point of view. The study of the Frenkel-Kontorova model with kinetic energy terms has found the two distinct different regimes appear in the parameter space specifying the model: the superlubricity and the friction regimes. Depending on the parameters such as initial velocity and the interfacial potential amplitude, we have found the novel frictional property in which the sliding velocity initially does not change for a while, but it suddenly decreases at unexpected time and later the sliding speed recovers for some period, consequently the mass center sliding velocity shows Brownian motion. This paper discusses the mechanism of the sliding speed’s sudden drop, i.e., the catastrophe of the breakdown of the superlubricity from the viewpoints of nonlinear oscillation. The problem of what triggers the catastrophe is studied by examining whether the chaotic vibration exists in the dynamic Frenkel-Kontorova model.

Keywords: Nano Tribology, Modelling in Tribology, Friction, Non-linear Dynamics, Chaos in Friction