랜덤 필드를 고려한 회전 블레이드 고유진동수의 불확실성 정량화 방법

Abstract

The natural frequencies of a rotating blade are determined by the parameters such as material properties of the blade, area and area moment of inertia of a blade cross section and a rotating speed. The parameters always have uncertainties caused by manufacturing tolerances, material irregularities and uncertain operating conditions. Since the parameter uncertainties lead to the uncertainties of natural frequencies, reliability based design should be conducted through the uncertainty quantification of the system. For the uncertainties of the area and area moment of inertia, random fields should be considered since the uncertainties of the area and area moment of inertia are the function of spatial variables. Therefore, an uncertainty quantification method of natural frequencies considering the random fields needs to be developed. In this paper, an uncertainty quantification method of natural frequencies of a rotating blade considering random fields was proposed employing a stochastic spectral method using polynomial chaos expansion (PCE). Compared to the Monte-Carlo simulation results, the accuracy and effectiveness of the proposed method was validated.