Lamb-Waves for Air-coupled Ultrasonic Testing with one-sided Access
Abstract »Usually the air-coupled ultrasonic testing (ACU) is carried out by through-transmission technique which requires a two sided access of the test component. Using this method we already have installed with our partners Robo Technology and Ostertag three 10- axis robot equipments for aerospace components with dimensions up to 20 m in Germany and Switzerland.
Our research-project BUC sponsored by the German government is focused on ACU with a one-sided access of the test component. Highlights are the application of Lamb waves and a fast data recording. This paper presents the developed array technique with 8 elements and a fast recording of the wave field. The array technique enables the recording of the wave field of one square meter in five minutes which is 7 times faster compared with a one channel system. The excitation of Lamb waves can be carried out by glued actuators or by angular incidence of air-coupled transducers. First results of damage detection in monolithic CFRP and GFRP components and in sandwich components with CFRP skins and honeycomb cores will be presented in this paper.
Biography: Dipl.-Phys. Dr.-Ing. Wolfgang Hillger, studied physics at the University of Braunschweig and received his PhD in 1983 at the University of Braunschweig.
Since 1978 he has been in charge at DLR (German Aerospace Center) until 2013. Currently he is developing ultrasonic methods ultrasonic imaging of internal defects in materials with high specific inhomogeneity such as composites. He is the author of more than 100 publications. In 1983 he founded his own company, Ingenieurbüro Dr. Hillger, ultrasonic techniques, which develops and produces special ultrasonic imaging systems of modular design. Highlights are high-frequency ultrasonic inspections up to 200 MHz and air-coupled systems for industrial applications (Airbus Helicopters and Ruag Space). www.dr-hillger.de