Abstract:

There are some problems with the traditional modal test method by pasting vibration sensors, such as influences of additional sensor mass, low mode shape resolution, etc. In order to solve these problems, 3-D scanning measuring technique based on laser Doppler vibrometry and robot platform are studied. Taking the case of liquid rocket engine (LRE) combustion chamber and oxidant entrance pipe, modal tests based on 3-D scanning measuring technique are carried out and high spatial resolution mode shapes are obtained. The effect of the additional mass of the sensors on the pipe modal test results is analyzed quantitatively. The results show that 3-D scanning measuring method has the advantage of high precision, fast test speed, and unlimited number of measuring points, etc.

Key words: 3 D scanning, Laser Doppler vibrometry, Liquid rocket engine, Robot