| Abstract:In order to obtain the multi-parameter loading spectrum and joint probability distribution of the low-pressure turbine shaft
of an aeroengine under service conditions, based on the aerodynamic similarity criterion of the engine, the aerodynamic load model was
established by using the multiple nonlinear regression method. Through the reasonable simplification of the rotor and support structure, the
maneuver load model was established by using the structural mechanics theory. Combined with the in-flight measurement parameters of
the engine in service, the aerodynamic torque, aerodynamic axial force, and dynamic bending moment profile of the low-pressure turbine
shaft were rapidly converted. On this basis, the peak-valley detection and Rainflow counting were carried out on the load profile to form the
peak-valley cycle matrix of the load. In order to consider the correlation between loads, the kernel density method was used to estimate the
marginal probability distribution of various load variables, and the Copula function was used to construct the joint probability distribution
function of the low pressure turbine shaft load, and the optimal distribution function was determined through the goodness of fit test. The
results show that compared with the statistical data, the joint probability distribution function established has better calculation accuracy
and can meet the needs of engineering applications. |
