A finite element transient response analysis method of a rotor-bearing system to base shock excitations using the state-space Newmark scheme and comparisons with experiments

Turbomachinery such as turbines, pumps and compressors, which are installed in transportation systems, including aircraft, ships and space vehicles, etc., often perform their critical missions and are exposed to potential dangerous impact environments such as base-transferred shock forces. In this study a transient response analysis technique of a rotor system is proposed. The study involves applying the generalized finite element modeling method of a rotor-bearing system considering a base-transferred shock force along with the state-space Newmark method of a direct time integration scheme based on the average velocity concept. Experiments are performed to a test rig of a mock-up rotor-bearing system with a series of half-sine shock waves imposed by an electromagnetic shaker, and quantitative error analyses between analytical and experimental results are carried out. The results show that the transient responses of the rotor are sensitive to the duration times of the shocks. In particular, in cases where the frequencies, 1/(2×duration time), of the shock waves are close to the critical speed of the rotor-bearing system, resonances may occur and the transient responses of the rotor are consequently amplified. Overall, the analytical results agree quite well with the experimental data.