• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2025, Vol. 61 ›› Issue (1): 162-171.doi: 10.3901/JME.2025.01.162

Previous Articles    

Comprehensive Application of Implicit Trapezoidal Rule with Numerical Jacobian in Rotor Dynamics

WU Jie1, YU Zhihao2   

  1. 1. School of Naval Architecture &Ocean Engineering, Jiangsu University of Science and Technology, Zhenjiang 212100;
    2. College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016
  • Received:2024-02-03 Revised:2024-08-18 Published:2025-02-26

Abstract: In recent years, geometrically exact beam theory is widely used in rotor structural dynamics to model composite blade undergoing large deflections. The relationship between movements and elastic deformations based on this theory shows strong nonlinearity and the generalized forces term is complex and huge. Therefore, it is difficult to derive the Jacobian matrix and determinant of the blade dynamics equation in analytical form, which brings great challenges to the implicit integration method. A trapezoidal integration utilizing numerical Jacobian matrix is proposed to solve the dynamic equations of helicopter rotor blade, in which the Jacobian matrix and stiffness matrix are numerically computed by central difference method with Romberg extrapolation scheme. Accuracy of the methods is evaluated on dynamic problems from one cantilevered beam and the other fully articulated rotor blade. Numerical stability and efficiency are also investigated by changing update policies of Jacobian matrix and mesh configurations of typical rotor blade. Numerical results show that the integration method with numerical Jacobian performs well on predicting natural frequencies and transient responses in rotor dynamics.

Key words: rotor dynamics, numerical integration, Jacobian matrix, extrapolation method, quasi-Newton method

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