This paper addresses ultrasonic investigations of the pore content in CFPR laminates as part of the German research project MaTech. Project partners are Airbus, Bremen, Ingenieurbüro Dr. Hillger, Braunschweig, and TuTech, Hamburg-Harburg, with DLR, Braunschweig, as a subcontractor. As backwall echo evaluations are not possible in the skins of sandwich components, investigations in echo-technique had to be carried out with the aim of optimising the test parameters. Based on these results, a portable ultrasonic system with C-scanning for pore content evaluation has been developed (Demonstrator). This paper also presents results of quantitative pore measurements. Basic investigations on specimens with different thicknesses (1.4 to 9.1 mm) and with foil delaminations of different sizes in different depths were carried out. The results were used to derive optimal acoustical parameters and to create an improved ultrasound set-up ('demonstrator') for the pulse-echo technique: - focussed and extreme broadband transducer in a C-scanning system; - high depth independent resolution up to 10 mm thick CFRP-components; - optimised components of the demonstrator are: avalanche pulser with high power above 10 MHz, different filters, low-noise preamplifier, main amplifier with DAC, ADC with 100 Msamples/s; - Windows.-based software for ultrasound settings, scanner control, data acquisition, C-scan display, and histogram evaluation for calculating the porosity in volume-%.
Determination of porosity in aerospace structures by ultrasonic pulse echo technique
Bestimmung der Porosität in Luftfahrtstrukturen mittels Ultraschall-Impulsechotechnik
2002
7 Seiten, 5 Bilder, 3 Quellen
Conference paper
Storage medium
English