Abstract:

An improved identification method based on the mode superposition method for dynamic bending moment responses of flight vehicles is proposed in this paper. A frequency domain integration algorithm is introduced to avoid the problems caused by the tendency eliminating and signal filtering when using the time-domain integration method. Firstly, the displacement response of the flight vehicle is obtained by integrating the acceleration responses twice. Then, the generalized displacement is calculated by the mode superposition method. Finally, the dynamic bending moment response is identified by utilizing the modal moment. The validity of this approach is verified through an experiment on a cantilever beam, where the results identified by using both the time-domain integration and frequency-domain integration method are presented. It is demonstrated that the results obtained by the improved method are closer to the real moments than that obtained by the classical time-domain method, namely the improved method has a higher accuracy. Furthermore, the proposed method is applied to estimate the dynamic bending moment responses of a vehicle during the flight, and the results are given.

Key words: Mode superposition method, Response moment identification；Frequency domain integration