Composites Design and Manufacture (Plymouth University teaching support materials)
Non-Destructive Testing (NDT) of advanced composites.
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PowerPoint presentation (778 KB file)

Summerscales [1-3], Burt and Smith [4], Karbhari [5], Fahr [6], Ibrahim [7] and Wang et al [8] have reviewed the use of non-destructive evaluation/examination (NDE) or NDT for fibre-reinforced composite materials/structures.  The applications of NDE/NDT can be considered to fulfil three functions (Table 1):

Table 1:  The functions of NDT
For samples in the laboratory For structures during manufacture and service
initial inspection of test samples confirmation of structural integrity.
monitoring sample tests in progress monitoring components under service loads, especially when changing over time,
or verification of structural integrity for life extension.
analysis of reasons for failure analysis of reasons for failure.

The various techniques can be arranged under three categories and further sub-divided by operating frequency albeit that some overlap may occur (Figure 1):

NDT techniques vs frequency
Figure 1: The various NDT techniques mapped to frequency

In the list which follows, references are provided for recent books or review articles pertinent to each topic.  Working from high frequency/short wavelength, the various techniques in each of the three categories are:

The electromagnetic spectrum.
  • Spectroscopy.
  • Mechanical vibration.
  • Summerscales [1] presented a preliminary assessment of the capabilities of the various NDT techniques for the detection of a variety of composites issues in the Table below where green indicates an established technology and orange indicates a technique with limited applicability or potential for development:

    defects vs NDT technique

    Baker et al [82] have similarly summarised the advantages and disadvantages of conventional NDI techniques in Table 1 (only accessible with a journal subscrption) of their paper.

    Signal processing and Probability of Detection (POD)

    Leavey et al [83] have presented an introductory tutorial on the use of wavelet analysis for signal processing in this context.  Yella et al [84] have recently reviewed the use of artificial intelligence techniques for the automatic interpretation of data from NDT.  Addin et al [85] have reviewed the use of neural networks in the prediction and detection of failures in laminated composite materials, with specific reference to NDT by vibration mode and frequency, use of Lamb waves and electrical conductivity.  Gros [86, 87] has reviewed the use of data fusion for handling multiple data sources in NDT.

    Backman [88, 89] has considered how safety methods can be made available to the engineering community without requiring huge statistical databases for use in reliability analysis.  The book considers the probability of safe flight, and is thus perhaps essential reading for those involved in aerospace structural design, although much of the analysis is undertaken at the level of orders of magnitude rather than in fine detail.  Of particular relevance here is the consideration of probability of detection against damage size for various regions [Figure 3] and the ability of each non-destructive testing technique relative to the respective damage sizes.  Wall et al [90] have considered probability of detection (POD) data in industrial applications and suggest that could be benefits from the use of simple POD generator models validated against experimental data with a more structured and standardised approach to the use and correction of POD data (using expert judgement, modelling and signal-based methods).

    Backman probability of detection
    Figure 3: Probability of Detection (POD) against damage size (after Backman [88]).

    The various NDT techniques have an important role to play in both Condition Monitoring (CM) and Structural Health Monitoring (SHM) which are covered in a lecture delivered to both module MECH512 Design for Structural Integrity and MECH 513 Smart Materials and Intelligent Structural Systems.



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    Further reading (reverse chronological order)

    1. A Fahr, Aeronautical Applications of Non-destructive Testing, Destech Publications, lancaster PA, 2014.  ISBN 978-1-60595-120-1.
    2. VM Karbhari, Non-destructive evaluation (NDE) of polymer matrix composites: techniques and applications, Woodhead Publishing, Cambrdge, 2013.  PU CSH Library
    3. MA Drewry and GA Georgiou, A review of NDT techniques for wind turbines, Insight, March 2007, 49(3), 137-141.
    4. BW Drinkwater and PD Wilcox, Ultrasonic arrays for non-destructive evaluation: a review, NDT & E International, 2006, 39(7), 525-541.
    5. David J Smith, Reliability, Maintainability and Risk - Practical Methods for Engineers including Reliability Centred Maintenance and Safety-Related Systems - seventh edition, Elsevier, 2005.  ISBN13: 9780-7506-6694-7.  PU CSH Library.
    6. RA Pethrick and D Hayward, Real time dielectric relaxation studies of dynamic polymeric systems, Progress in Polymer Science, 2002, 27(9), 1983-2017.
    7. Koji Asami, Characterization of heterogeneous systems by dielectric spectroscopy, Progress in Polymer Science, 2002, 27(8), 1617-1659.
    8. R Chandra, SP Singh and K Gupta, Damping studies in fiber-reinforced composites: a review, Composite Structures, 1999, 46(1), 41-51.
    9. Gi Xue, Fourier transform Raman spectroscopy and its application for the analysis of polymeric materials, Progress in Polymer Science, 1997, 22(2) 313-406.
    10. J Summerscales, Non-Destructive Testing of Fibre Reinforced Plastics Composites - volume 2, Elsevier Applied Science Publishers, Barking, 1990.  ISBN 1-85166-468-8. Now distributed by Springer.  PU CSH Library.
    11. J Summerscales, Non-Destructive Testing of Fibre Reinforced Plastics Composites - volume 1, Elsevier Applied Science Publishers, Barking UK, September 1987.  ISBN 1-85166-093-3. Now distributed by Springer.  PU CSH Library.

    The British Institute of Non-Destructive Testing has published a useful series of introductory texts under the title NDT Fundamentals,
    The ultrasonics papers are made available here to University of Plymouth students with the kind permission of the British Institute of Non-Destructive Testing and of the author.

    FREE three-part whitepaper series for thermographers:

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    Updated by John Summerscales on 31-May-2024 17:28. Terms and conditions. Errors and omissions. Corrections.