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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2015, Vol. 36 ›› Issue (6): 1848-1857.doi: 10.7527/S1000-6893.2014.0183

• Solid Mechanics and Vehicle Conceptual Design • Previous Articles     Next Articles

Physical mechanism investigation of coaxial helicopter ground resonance

HU Guocai, LIU Xiangyi, LIU Shuyan, WANG Yunliang   

  1. Department of Airborne Vehicle Engineering, Naval Aeronautical and Astronautical University, Yantai 264001, China
  • Received:2014-06-09 Revised:2014-07-14 Online:2015-06-15 Published:2014-09-05
  • Supported by:

    Aeronautical Science Foundation of China (20145784010)

Abstract:

In order to understand the coupling interaction between upper/lower rotor and fuselage of coaxial helicopter, a time-frequency analytical method is presented to analyze physical mechanism of coaxial helicopter ground resonance. An analytical model for coaxial articulated rotor helicopter ground resonance with structural damping is established, considering periodic lag motion DOFs (upper rotor and lower rotor), body pitch rotation DOF and body roll rotation DOF. Eigenvalue calculation and numerical integration of disturbance equations of motions are used to obtain modal characteristics and time-domain response characteristics of coaxial helicopter ground resonance, and the interaction between rotors and body is revealed according to the response of various DOFs. The analytical results show that regressive lag mode with upper rotor characteristics is the most instability mode. In dynamic instability region, coaxial helicopter ground resonance is mainly due to energy transferred between periodic lag motion of upper rotor and body roll rotation. For this instability mode, energy transferred between periodic lag motion of lower rotor and body roll rotation also exists and it can enhance ground resonance instability of coaxial helicopter.

Key words: coaxial helicopter, ground resonance, physical mechanism analysis, eigenvalue, dynamic response

CLC Number: