LIFE CALCULATION OF FIRST STAGE COMPRESSOR BLADE OF A TRAINER AIRCRAFT

This paper is concerned with. life estimation of a compressor rotor blade of an engine at the Air Force Institute of Technology in Warsaw used in a trainer aircraft. A bird strike is simulated by two or three blade passage blocks in the incoming flow and the pressure field is obtained from a CFD code. For the blade the Campbell diagram is prepared and the critical speeds are identified. The alternating pressures corresponding to the critical speed are obtained from an FFT. A nonlinear damping model is estimated using Lazan's hysteresis law; the equivalent viscous damping model is determined as a function of reference strain amplitude in the given mode of vibration at the rotational speed. An iterative solution is developed with the nonlinear damping model and the resonant stress and location is determined. The life at this critical speed is determined using a cumulative damage criterion.