This study proposes a dual-sided particle damper balancing method to counteract eccentric inertial forces in rotor systems and suppress rotational vibrations. Particle–wall and inter-particle interactions play a critical role in determining the dynamic behavior of systems equipped with particle dampers. However, these interactions remain poorly understood. To the best of our knowledge, neither the Finite Element Method (FEM) nor the Discrete Element Method (DEM) alone can adequately capture the coupled interaction between particles and mechanical components. To address this limitation and accurately model these complex interactions, we propose a coupled DEM–FEM approach to analyze the dynamic behavior of an eccentric rotor system incorporating particle dampers. The effects of rotational speed and particle size on system dynamics were systematically investigated. The dynamic responses examined include radial displacement, displacement spectra, bearing stresses, and the kinetic and strain energy of the rotor system. Numerical results reveal that the unbalanced shaft exhibits significantly more unstable dynamic behavior than the balanced shaft. Moreover, bearing stresses in the unbalanced shaft are substantially higher than those in the balanced shaft. The collisions and friction between the damping particles and mechanical components effectively reduce radial displacement, vibration amplitude, bearing stresses, kinetic energy, and strain energy of the rotor system. The installation of particle dampers leads to a marked reduction in vibration levels. In particular, particle dampers with a diameter of 2.0 mm demonstrate the most effective damping performance. These findings confirm that particle dampers provide robust vibration suppression across a wide frequency range and in multiple directions [1-3]. REFERENCES [1] H.V. Panossian. Structural damping enhancement via non-obstructive particle damping technique. J. Vib. Acoust., Vol. 114, pp. 101-105, 1992. [2] Y.C. Chung, and Y.R. Wu. Dynamic modeling of a gear transmission system containing damping particles using coupled multi-body dynamics and discrete element method. Nonlinear Dynam., Vol. 98, 129-149, 2019. [3] C.C. Liao, Y.C. Chung, and C.H. Weng. A study on the energy dissipation mechanism of dynamic mechanical systems with particle dampers by using the novel energy method. Nonlinear Dynam., Vol. 111, pp. 15955-15980, 2023.