Hamed Ahangardarabi - Faculty of mechanical Engineering Department, Islamic Azad University-Sari Branch, Sari

Military and commercial aircrafts during their functions are always subjected to damage and failure, which is a serious threat to their safe working. Therefore, if it is possible to correctly and timely identify the defects of a structure, such as cracking, then it is possible to carry out subsequent operations, such as repairs or replacement of defective parts in order to maintain health and increase their life span. One of the most basic concepts engineers are dealing with here is the Structural Health Monitoring (SHM). SHM is based on the status monitoring and examining a lot of involved parameters through the receipt and analysis of information. The goal of this paper is to study the Comparative Vacuum Monitoring method (CVM), known as one of the newest methods in SHM for detecting defects on the aircraft's structures. A CVM unit was designed and manufactured, which is the assembly of many parts such as silicon sensors, printed circuit board (PCM)), and also vacuum pump, hose and connections, T-fitting, valves and stop valve, stop bell and etc. This unit was utilized to detect cracks on some artificial samples with preset defects, and also on some real and industrial aircraft parts. The findings have revealed that the CVM unit is capable to detect the cracks on aircraft structures, and it is possible to carry out more detailed theoretical and practical studies on the industrial samples, which also has the ability to detect cracking in flight mode.

Mechatronics, Structural Health Monitoring (SHM), Comparative Vacuum Monitoring method (CVM), Crack Detection.