Measurement Technique and Result Analysis of Helicopter Rotor Blade Structural Vibration Load

The measurement of helicopter rotor blade structural load amid flight has always been the difficulty in flight test. In this paper, the principle of the existing blade structural load measurement method (electrical measurement method) was analyzed, and the problem of physical decoupling in the use of this method was expounded. As a weak signal measurement, the electrical measurement method also has electromagnetic interference problems, which will affect the flight test period of blade structural load measurement. Therefore, a numerical decoupling measurement method based on fiber Bragg grating (FBG) was proposed. Then, the new method was applied and verified in the load equation modeling test and the flight test under the real atmospheric environment was carried out. Through comparing and analyzing the measured data of the new method and the electrical measurement one, the correctness of the FBG data decoupling method was validated. The results indicate that the method proposed in this paper can effectively improve the efficiency of blade load equation modeling engineering and has good application value.