Loughborough University
Leicestershire, UK
LE11 3TU
+44 (0)1509 263171
Loughborough University

Loughborough University Institutional Repository

Please use this identifier to cite or link to this item: https://dspace.lboro.ac.uk/2134/17635

Title: Toward the 3D characterisation of GLARE and other fibre-metal laminate composites
Authors: Smith, Robert A.
Veres, Istvan A.
Pinfield, Valerie J.
Issue Date: 2014
Publisher: British Institute of Non-Destructive Testing
Citation: SMITH, R.A., VERES, I.A. and PINFIELD, V.J., 2014. Toward the 3D characterisation of GLARE and other fibre-metal laminate composites. Proceedings, NDT 2014 - 53rd Annual Conference of the British Institute of Non-Destructive Testing, 9th - 11th September 2014, Manchester, UK.
Abstract: Fibre-metal laminates such as GLARE (alternating glass-fibre composite and aluminium layers) are seeing increasing usage on critical aircraft structures due to their enhanced fatigue resistance compared with unreinforced metal. They can be inspected for overall quality using through-transmission ultrasound, but it is very difficult to determine the depth or nature of any defect in the structure in order to assess its importance or severity. As a result, manufacturing scrap rates are higher than desirable and designed components are heavier in order to mitigate risk due to inadequate information. Defect-depth information is buried in the ultrasonic response but is difficult to extract due to the high reflection coefficients of the interfaces and the variable glass-fibre layer thicknesses. This paper presents the potential for using model-based multi-dimensional optimisation to determine the layer thicknesses and depth locations of anomalies in the ultrasonic response due to delaminations or porosity. Numerical (FEM) and analytical methods are presented to model the ultrasonic response of fibre-metal laminates, calculated as the steady-state harmonic response of the layered medium. These frequency-domain responses can be used to determine the individual layer thicknesses and depth locations of anomalies by multi-dimensional optimisation. Investigations on the accuracy and the limitations of the method for the 3D characterisation of laminates will be presented. In addition, the evaluated frequency-domain responses show that the high reflection coefficients in combination with the periodic arrangement of the layup effectively mimic the behaviour of a one-dimensional phononic crystal. In the through-transmission ultrasound response, stop bands arise where the transmission is close to zero. None of the resonance frequencies of a laminate - even one with a finite number of layers - can lie within a stop band. However, the presence of a defect in a layer, or different material properties or thickness, can cause the defect modes, i.e. eigenmodes, to shift into the expected stop bands. This might open new possibilities in the nondestructive testing of fibre-metal laminates, which will be elaborated in the presented paper.
Description: This is a conference paper.
Version: Accepted for publication
URI: https://dspace.lboro.ac.uk/2134/17635
Publisher Link: http://www.bindt.org/
ISBN: 9781634395038
Appears in Collections:Conference Papers and Presentations (Chemical Engineering)

Files associated with this item:

File Description SizeFormat
NDT2014 Smith, Veres and Pinfield - GLARE - Final with Reference.pdfPublished version759.13 kBAdobe PDFView/Open


SFX Query

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.