Stochastic finite element modeling and response analysis of rotor systems with random properties under random loads

Abstract

Random properties and random loads are highly important in rotor dynamic analysis because they cause system dynamic responses to behave randomly. In this paper, a stochastical finite element of rotating shaft based on Timosheko beam theory is proposed for rotor system modeling, in which material and geometric random properties are considered one-dimensional stochastic field functions. A random response analytical method is developed to determine the statistics of the dynamic responses of stochastical rotor systems under random loads. The numerically obtained whirl speed of a turbopump rotor system is compared with the test data to validate the proposed model, and good agreement is observed. Linear and nonlinear turbopump rotor systems are employed to compare the results obtained from the proposed model and the Monte Carlo simulation. The numerically predicted results, which coincide well with Monte Carlo simulation data, demonstrate the feasibility and efficiency of the proposed stochastic model and method for actual rotor system analysis and design.