Non-contact ultrasonic NDE of carbon/carbon composite

B. R. Tittmann, M. C. Bhardwaj, L. Vandervalk

Research output: Contribution to journalConference articlepeer-review

6 Scopus citations


Non-contact materials NonDestructive Evaluation techniques with ultrasound are useful for many industrial settings particularly where high temperatures or speeds are involved. This paper presents results on non-contact ultrasonic wave propagation through thick carbon/carbon material. Specifically, at an air distance of about 200 mm carbon/carbon aircraft brake sections about 25 mm thick were examined in through-transmission at 250 kHz with signal-to-noise ratios of about 30 dB. In regions of delaminations the amplitude decreased sufficiently to indicate the presence of a flaw. The non-contact, air-coupled data are compared with those obtained with the more traditional dry-contact measurements. Non-contact velocity measurements are also presented with time-of-flight data obtained with phase stability of a few nanoseconds. These results are discussed in terms of newly developed air-coupled transducers and digital signal processing electronics.

Original languageEnglish (US)
Pages (from-to)325-332
Number of pages8
JournalCeramic Engineering and Science Proceedings
Issue number3
StatePublished - 1999
EventProceedings of the 1999 23rd Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - Cocoa Beach, FL, USA
Duration: Jan 25 1999Jan 29 1999

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Materials Chemistry


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