NDT.net - June 1999, Vol. 4 No. 6

Table of Contents ECNDT '98

Session: Aerospace

D-Sight technique for rapid impact damage detection on composite aircraft structures

J.H. Heida - NLR, Structures and Materials Division,
A.J.A. Bruinsma - TNO Inst. of Applied Physics, The Netherlands.
Corresponding Author Contact:
Email: heida@nlr.nl
Homepage: http://www.nlr.nl




D-Sight technique

D-Sight systems



Conclusions and recommendations

  1. A set of equations has been derived to establish the relation of various parameters of a D-Sight set-up. A D-Sight index has been introduced to quantify the inspection results.
  2. The sensitivity of the D-Sight technique corresponds to indent depths in the range of 0.01 to 0.05 mm. The D-Sight technique can reliably detect indents with indent depth in the range of 0.1 mm on smooth and glossy surfaces, and also on mat surfaces if a highlighter is applied.
  3. The D-Sight technique is capable of detecting significant impact damage, with a damage area equal to or larger than 5 cm2 , within a field of view of about 0.25 m2 .
  4. Inspections on a full-scale composite structure show that the D-Sight technique compares favourably with other inspection techniques, for the detection of impact damage and other defects with surface deformation.
  5. It is recommended to further develop image processing procedures for the automatic detection and analysis of defects (e.g. type and size) and for the comparison of inspection results with previously recorded results (e.g. during manufacturing).
  6. It is recommended to further develop software for the incorporation of the structure configuration and for the archiving of the inspection locations and inspection results.


  1. Erdl, M.; Woithe, K., "Specification of requirements", EUCLID RTP 3.1 reports EUC-DOC-2110/ 2120/2130-01-IABG, Ottobrunn, 1993.
  2. Reynolds, R.L.; Karpala, F.; Clarke, D.A. and Hageniers, O.L., "Theory and applications of a surface inspection technique using double-pass retroreflection", Optical Engineering, Vol. 32, No. 9, pp. 2122-2129, 1993.
  3. Komorowski, J.P.; Gould, R.W. and Marincak, A., "Location of impact damage sites in composite aircraft structures", NRC/IAR report LTR-ST-1904, Ottawa, 1992.
  4. Diffracto Limited, "DAIS - D SIGHT Aircraft Inspection System", User's manual, Windsor, Canada, 1995.
  5. Heida, J.H.; Bruinsma, A.J.A., "D-Sight method", EUCLID RTP 3.1 reports EUC-DOC-2610/ 2620/2630/2640/2650-01-NLR, Amsterdam, 1994.

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