Elastohydrodynamic lubrication (EHL) is a type of hydrodynamic lubrication in where the effects of elastic deformation of the lubricating surface appear. EHL occurs in various mechanical components, such as rolling bearings and gears. The lubricant film in EHL is extremely thin in the contact area. Numerical methods have the advantage of being able to reproduce and observe phenomena under various conditions at relatively low cost. In particular, the moving particle semi-implicit (MPS) method [1], which is a particle methods that has the advantages of free-surface flow and multi-physics simulations, is considered suitable for fluid lubrication simulations. Yamada et al. [2] developed a numerical method for fluid lubrication using a multiresolution particle method. In [3], they developed a simulation method for soft elastohydrodynamic lubrication using a multi-resolution MPS method, and succeeded in reproducing the lubricant film thickness and fluid pressure under soft elastohydrodynamic conditions, in which the fluid was considered incompressible and the viscosity coefficient was constant. The next challenge is hard EHL simulation, in which the viscosity coefficient depends on the fluid pressure. The present study developed a numerical method for solving hard EHL problems by enhancing the method proposed by Yamada et al. [3] and considering the viscosity change due to pressure. A hard EHL problem in line contact was simulated using the developed method. The results indicated that the film thickness and pressure were close to those obtained by the semi-analytical solution of the Reynolds equation, except for the reproduction of the pressure spike. REFERENCES [1] S. Koshizuka and Y. Oka, “Moving-Particle Semi-Implicit Method for Fragmentation of Incompressible Fluid”. Nuclear Science and Engineering, 123-3, 421-434 (1996). [2] D. Yamada, T. Imatani, K. Shibata, K. Maniwa, S. Obara and Hi. Negishi, “Application of improved multiresolution technique for the MPS method to fluid lubrication”, Computational Particle Mechanics, 9, 421-441 (2022) [3] D. Yamada, et al., “Soft Elasto-Hydrodynamic Lubrication Simulation by a Multi-Resolution Particle Method”, 15th World Congress on Computational Mechanics (WCCM-XV), (2022) ACKNOWLEDGEMENT This work was supported by the Japan Society for the Promotion of Science (Grants-in-Aid for Scientific Research, Grant Nos. 21K03847 and 23K04248).