For the structural characteristics of a certain type of missile turbofan engine

a rotor-support-casing whole model established. The rotor and casing were modeled by means of the finite element beam model; the support was modeled by lumped-mass model; support looseness fault model was also introduced. The coupled system response was obtained by the numerical integral method. Impact characteristics of symmetrical stiffness and asymmetric stiffness models were analyzed based on casing acceleration signal. It is found that looseness fault could lead to acceleration time-domain waveform of casing with up-down asymmetrical impact characteristics and multiple frequency characteristics in frequency spectrum. Time-domain waveform and frequency spectrum characteristics of the simulation results and the actual missile turbofan engine test data are very consistent. Asymmetric stiffness looseness model is verified more suitable for missile turbofan engine looseness fault modeling.