Vibration based debonding damage detection of thermal protection structures
Debonding damage identification method based on the frequency response function measurement is proposed to meet the demand for rapid on-site nondestructive inspection of typical aircraft thermal protection structures.Firstly,a finite element model of the thermal protection structure with debonding damage was established using finite element method and vibration characteristic analysis was performed.In addition,the local stiffness reduction caused by debonding damage and the sensitivity of the frequency response function to debonding damage were analyzed.Then,a characteristic frequency range for debonding damage identification was given,and a debonding damage index was defined.Finally,a thermal protection structure with debonding damage was tested by using a force hammer and laser Doppler vibrometer.The experimental results show that when the debonding area reaches 60%,the debonding damage index is more than doubled compared to the healthy parts,and when the debonding area reaches 80%,the debonding damage index is more than five times that of the healthy parts,which verifies that the proposed method in this paper is able to identify the debonding damage of thermal protection structure effectively.
NETL
NSTL
万方数据
维普
