Abstract
In order to calculate high-speed transient phenomena of a rotor-system such as rotor collision with stator due to blade loss, a very small incremental time step is required in the integration. But a small time step is known to cause a numerical instability when a direct integration such as Newmark-β method is applied in terms of physical coordinate. This paper presents a method using constraint real mode synthesis in which modes are derived from neglecting gyro-moment and fixing bearing connection freedoms to be zero. This method is proved to be highly stable and also to have good accuracy and efficiency.
