The regional aircraft with a turbofan gas turbine engine, created in Russia, is successfully operated in the world market. Further increase of the life and reduction of the cost of the life cycle are necessary to ensure the competitive advantages of the engine. One of the units limiting the engine life is the compressor rotor. The cyclic life of the rotor depends on many factors: the stress-strain state in critical zones, the life of the material under low-cycle loading, the regime of engine operation, production deviations (within tolerances), etc. In order to verify the influence of geometry deviations, the calculations of the model with nominal dimensions and the model with the most unfavorable geometric dimensions (worst cases) have been carried out. The obtained influence coefficients for geometric and weight tolerances are then used for probabilistic modeling of stresses in the critical zone. Rotor speed and gas loads on the blades for different flight missions and engine wear are determined from the corresponding aerodynamic calculations taking into account the actual flight cycles (takeoff, reduction, reverse) and are also used for stress recalculations. The subsequent calculation of the rotor cyclic life and the resource assessment is carried out taking into account the spread of the material low-cycle fatigue by probabilistic modeling of the rotor geometry and weight loads. A preliminary assessment of the coefficients of tolerances influence on stress in the critical zone can be used to select the optimal (in terms of life) tolerances at the design stage. Taking into account the actual geometric and weight parameters can allow estimating the stress and expected life of each manufactured rotor.

During the modernization of the low-pressure compressor of the regional aircraft engine, a flow separator made of polymer composite material was developed, which has less weight, is easier and cheaper to manufacture. However, the separator must undergo a series of tests before being installed on the engine, in particular the endurance tests, necessary to assess the fatigue strength margin. A method for determining the endurance limit of a large part of an aircraft engine is developed in the presented work and consists in replacing the tests of the entire separator with tests of individual structural elements cut from the part. The shape, dimensions and fixation of the elements have been chosen in such a way that their own test frequency was close to the natural frequency of the flow separator on the engine. The natural oscillation frequencies and places of maximum dynamic stresses have been determined before testing on three-dimensional models of the flow separator and elements cut from it. As a result, the structural elements have been tested until appearance of fatigue cracks which allowed to assess the endurance limit and evaluate fatigue strength margin of the separator.

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A technology for robust multi-criteria optimization of the fan blades with real deviations of airfoil geometry is proposed which includes simultaneously solving aerodynamic and mechanical integrity problems as well as balancing and arranging the blades in the row. In accordance with this technology, automated measurements of blades airfoil geometry (more than 1200 points) are used to automatically create a blade “cold” 3D model, meshing, and static and dynamic analysis of mechanical integrity. Then the model and mesh are automatically transformed in a “hot” condition and an aerodynamic analysis is carried out to estimate the measured geometry influence on fan parameters. Finally, arrangement of blades in the row is carried out based on static moments and aerodynamics analysis. The final stages of this technology are presented in this paper more detail.