In aerospace, nondestructive testing (NDT) is an essential activity in order to verify the structures behavior during stress or loading cycles. Also NDT is used for diagnosis and find defects which can be dangerous for the integrity of the structure during its life-cycle. Among many NDT techniques, those based on optics and laser are contactless and usually based on imaging systems. This allows faster inspection compared to traditional methods based on point measurements with lengthy scanning. In this lecture, we will give an overview of various methods and techniques developed at the Space Center of Liege since 25 years, with the aim of measuring the mechanical behavior of satellite structures under load, as well as detecting defects in aerospace composite structures. In particular, we will discuss methods like analog and digital holographic interferometry, speckle and speckle shearing interferometry, thermography, terahertz imaging.

Dr. Marc Georges works at the space center of Liege since 1990. He worked on several project on development of innovative dynamic holographic interferometer for aerospace nondestructive testing and passed his PhD thesis on that subject in 1998. After that he developed different project in coherent imaging and optical metrology. He is leader of the Laser and NDT laboratory since 2006. He developed further activities in coherent optical metrology and nondestructive testing, in relationship with aerospace industries. In particular, he led new researches in holography at long infrared wavelengths, and more recently in Terahertz waves. Besides this, he developed a more complete laboratory for NDT with various non-contact methods, such as thermography and laser ultrasonics. He has written typically 3 book chapters devoted to holographic nondestructive testing.