This paper describes two applications of this technique: (1) the inspection of thin CFRP-Laminates and (2) those of honeycomb components with Nomex cores and CFRP-skins. For all inspections the HFUS 2000 flaw detector is used. This modular system was optimised for these different applications.
Ultrasonic attenuation in composites is relatively high, and the scatter by the fibres reduces the signal to noise ratio. For composites and other new materials an ultrasonic imaging system has been developed . The computer controlled ultrasonic flaw detector HFUS 2000 provides high resolution inspections in the frequency range from 0.1 to 120 MHz and is of modular design. Results of thin CFRP laminates in immersions technique with a 50 MHz PVDF-foil-transducer are shown.
For honeycomb-sandwich components the attenuation increases very much at high frequencies. Therefore only frequencies below 1 MHz can pass through the whole thickness of these components.