Health Monitoring For Aircraft Structural System On The Heat-force Coupled Environment

In this paper, taking the torsion-resisted box of wing in an aircraft as an example, research work focuses on the technology of aircraft structural health monitoring under the heat-force coupled environment. It includes finite element analysis of the box model, data processing technology and experiment mainly.In the first part, after introducing the background of task, the mechanical characteristics of the box model are analyzed under both ordinary and heat-force coupled environment. The results indicate that the mechanical characteristics of the box model changed in the latter which will lead to faults easier. And then typical fault patterns of the box are simulated numerically. The box model characteristics changed under faults and normal by comparing with the normal.Secondly, the data of these above simulations are ayalyzed and processed with the help of Fourier Transform in order to study the appliance of Wavelet Transform in the field of aircraft structural health monitoring. The Wavelet Transform can overcome the limitation of Fourie Transform and has a better time and frequency characteristics. The fault data can also be described in both time and frequency domain. Next, basing introducing the Wavelet Packet Analysis theory, the "energy-fault" method is applied in aircraft structure health monitoring. And the faults can be recognized and diagnosed by analyzing the changes of energy in signals.An aircraft health monitoring experiment is introduced in the third part. The optimization design of sensors' layout in the box model is considered during the course of the experiment. By analyzing and processing the experiment data, the Wavelet Transform is proved to be feasible completely.