Abstract
Seizure occurs when a sudden heat generation at the real contact surface, called the flash temperature, becomes the source point, raising the surrounding temperature and progressing plastic flow. In previous experimental studies, in-situ observations of the contact surface between metals have been conducted, but the complete seizure process has still not been fully elucidated. We propose to apply the smoothed particle hydrodynamics (SPH) method to tribology, a solid friction simulation technique. This makes it possible to express mesoscale sliding surfaces that are difficult to express in terms of spatial scale using all-atom molecular dynamics and can predict frictional heat such as heat generation and heat conduction at the real contact surface, as well as mechanical properties such as large deformation and plastic flow. In this study, we used this simulation model to reproduce the mesoscale sliding surface of aluminum (Al) and titanium (Ti) by creating models with unevenness in the center. In this study, we performed a simulation of the sliding speed, frictional heat, and plastic flow for each material alone and for solid contact models of Al and Ti. As a result, heat generation from the center of the protrusions was confirmed for both metal materials, and then heat was diffused throughout the entire sliding surface. A similar trend is seen when a solid is in contact with a Ti solid, however, whereas the temperature rises overall at the sliding surface of Al, no significant heat diffusion is observed at the sliding surface of Ti, and considerable frictional heat is generated at the contact area. The results of the flash temprature and average temperature shown in this study are considered to indicate the physical properties of each material. In addition, plastic deformation was confirmed on the Al surface, suggesting that the generation of frictional heat and plastic deformation can be analyzed by sliding simulations.
