<p>Turbomachinery systems, particularly gas turbines, are essential to energy transformation processes and are widely used across various industries, including electricity generation and aerospace. Within these machines, the bolted-joint rotor is the critical component, its durability and stable operation significantly influencing the overall performance of the system. However, dynamic analysis of bolted-joint rotors often overlooks the nonlinear behavior at the pedestal support, which may result in an incomplete understanding of rotor dynamics. This study proposed a dynamic modeling approach for the bolted-joint rotor system that concurrently accounts for the nonlinear support stiffness at the pedestal and the piece-wise linear stiffness of the bolted joint. Utilizing finite element theory, a dynamic model of the bolted-joint rotor-support system is developed to investigate the effects of the nonlinear support stiffness and the bolt preload of the bolted joint on the rotor vibration characteristics. The numerical findings indicate that incorporating the nonlinear support stiffness of the pedestal results in diverse motion states for the bolt joint rotor system, including chaos, quasi-periodic motion, and period-two motion. Furthermore, the critical rotational speed of the system and the corresponding amplitude increase with higher bolt preload, which necessitates higher rotational speeds for the system to transition into period-two motion. The results of the present work can provide a theoretical foundation for enhancing the operational reliability of gas turbines and contribute to a deeper understanding of bolted-joint rotor dynamics.</p>