Vibration Probability Analysis of Aero-Engine Blades Based on Double Response Surface Method

In order to study the more accurate reliability of aero-engine blades when through out the region of resonance speed and occurred a short time resonance, considering the failure caused by common cause (the failure of stress and deformation caused by one factor of blade vibration), the double response surface method was proposed. The blade maximum deformation and stress were obtained through the modal analysis and harmonic response analysis. Selected the density, speed and aerodynamic force as input variables and deformation and stress as output response, the response surface mathematical model of the blade maximum deformation and stress was established. The blade reliability was obtained based on considering the speed, the aerodynamic force and material density. The results show that the reliability is 99.14% when the mean of blade allowable deformation is 2.45mm and variance of blade allowable deformation is 0.0368mm, the mean of blade allowable stress is 540MPa and variance of blade allowable stress is 8.1 MPa. Compared with the Monte-Carlo method, the feasibility and effectiveness of the double response surface method are validated when the blade occurs a short time resonance.