Influence of Mechanical Component Mass on the Dynamic Characteristics and Stability of a Four-Cable Mount System in Wind Tunnel Tests

Abstract

To investigate the impact of the mass of mechanical components on the dynamic characteristics of the system, the mass of cables, pulleys, and springs within a four-cable mount system is considered. The kinetic and potential energies of the mechanical components are further considered for the four-cable mount system, with reference to the aircraft model’s kinetic and gravitational potential energy, and the potential energy of the spring. The dynamics equation of the four-cable mount system under aerodynamic force is established based on the Lagrange equation. The system singularity and its bifurcation characteristics, and the alterations in the vertical position of the model centroid before and after considering the mass of the mechanical components, are examined under blowing conditions using the system dynamics equation. The mathematical expressions for the flight stability of the cable mount system are obtained by linearizing the system dynamics equation through a small perturbation, which identifies the factors influencing aircraft stability. By employing the small perturbation equation in conjunction with complex mode theory, the eigenvalues of the equation are computed to assess the effects of cable tension and suspension point positioning on system stability, both with and without consideration of the mass of mechanical components. The impact of the mass of each mechanical component and the change of the diameter of the cable and the material of the pulley on the rigid body modal frequency of the system was analyzed by solving the rigid body modal frequency of the system under blowing conditions.