Abstract
This paper investigates the correlations between transducer properties, defect size and depths, and the signal/noise ratio during ultrasonic inspection of polymeric composites. Samples of different fiber/matrix systems were produced, intentionally including artificial defects of various sizes and shapes. These specimens were inspected ultrasonically with transducers in the frequency range from 1-150 MHz. It could be seen that the 5 MHz transducer possessed the highest signal/noise ratio in most cases. High frequency transducers (f > 20 MHz) should be used for the inspection of thin walled part with high resolution. Finally, a transducer selection guide incorporating special usage terms for carbon fiber/epoxy resin composites is introduced. According to this catalogue, a 5 MHz transducer would be chosen for the inspection of a 40 mm thick resin compressor blade made of C fiber reinforced epoxy resin composite. In order to follow the contour of this three-dimensionally shaped part, a mechanical manipulator consisting of a newly developed joint configuration with altitude correction was built.