A Full-Field Stress Based Damage Assessment Approach for In Situ Inspection of Composite Structures

Article Preview

Abstract:

This paper describes the development of a stress / strain based in-situ damage inspection strategy focused around, but not exclusively, using thermoelastic stress analysis (TSA). The underlying philosophy is that defects and damage in a component or structure only constitute a cause for concern if these influence the stress field, i.e. the defect or damage acts as a stress raiser that reduces the service load limit. To assess this, it is necessary for the inspection method to map the distribution of stresses in the component, rather than the location and extent of an irregularity in the material. Imaging based techniques, such as TSA, digital image correlation (DIC) or digital speckle pattern interferometry (DSPI) provide non-contact maps of the surface stresses, deformations and/or strains. The full field data enables the engineer to evaluate if stress concentrations are present within the structure and, if data from a previous inspection is available, to assess if the distribution of stresses within the structure has changed from a previous 'undamaged' state. One of the key issues addressed in the current work has been the transition from a standard test setup, as typically used in laboratory work, to a more flexible (portable) setup relevant to industry requirements, e.g. site inspections. An approach that enables similar resolution (by comparison to current laboratory standard setups) stress and strain data to be captured using natural frequency excitation of a structure has been demonstrated on various full scale components.

You might also be interested in these eBooks

Info:

Periodical:

Key Engineering Materials (Volumes 569-570)

Pages:

3-10

Citation:

Online since:

July 2013

Export:

Price:

Permissions CCC:

Permissions PLS:

Сopyright:

© 2013 Trans Tech Publications Ltd. All Rights Reserved

Share:

Citation:

[1] P. Stanley, W.K. Chan, The application of thermoelastic stress analysis techniques to composite materials, Journal of Strain Analysis, 23 (1988) 137-143.

DOI: 10.1243/03093247v233137

Google Scholar

[2] J.M. Dulieu-Barton, P. Stanley, Development and applications of thermoelastic stress analysis, Journal of Strain Analysis, 33 (1998) 93-104.

DOI: 10.1243/0309324981512841

Google Scholar

[3] X. Ming, D. Kang, Corrections for frequency, amplitude and phase in a fast Fourier transform of a harmonic signal, Mechanical Systems and Signal Processing, 10 (1996) 211-221.

DOI: 10.1006/mssp.1996.0015

Google Scholar

[4] L. Zhu, Y. Xiong, B. Zhong, An approach for amplitude correction in line spectrum, Mechanical Systems and Signal Processing, 17 (2003) 551-560.

DOI: 10.1006/mssp.2001.1397

Google Scholar

[5] R.K. Fruehmann, J.M. Dulieu-Barton, S. Quinn, Thermoelastic stress and damage analysis using transient loading, Experimental Mechanics, 50 (2010) 1057-1086.

DOI: 10.1007/s11340-009-9295-9

Google Scholar

[6] D.A. Crump, J.M. Dulieu-Barton, J. Savage, Design and commission of an experimental test rig to apply a full-scale pressure load on composite sandwich panels representative of aircraft secondary structure, Measurement Science and Technology, 21 (2010).

DOI: 10.1088/0957-0233/21/1/015108

Google Scholar