Development of a rapid drop rest for surface quality inspection

Thang, Christopher Y. and Liew, Chin K. (2012). Development of a rapid drop rest for surface quality inspection. In: Andrei Kotousov, Raj Das and Stuart Wildy, Proceedings: the 7th Australasian Congress on Applied Mechanics (ACAM 7). 7th Australasian Congress on Applied Mechanics (ACAM 7), Adelaide, Australia, (905-914). 9-12 December 2012.

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Name Description MIMEType Size Downloads
Author Thang, Christopher Y.
Liew, Chin K.
Title of paper Development of a rapid drop rest for surface quality inspection
Conference name 7th Australasian Congress on Applied Mechanics (ACAM 7)
Conference location Adelaide, Australia
Conference dates 9-12 December 2012
Proceedings title Proceedings: the 7th Australasian Congress on Applied Mechanics (ACAM 7)
Place of Publication Barton, ACT, Australia
Publisher Engineers Australia
Publication Year 2012
Sub-type Fully published paper
ISBN 9781922107619
Editor Andrei Kotousov
Raj Das
Stuart Wildy
Start page 905
End page 914
Total pages 10
Collection year 2013
Language eng
Abstract/Summary In material bonding, the surface energy of the adherend can be an excellent predictor of adhesive bond strength. In this research, the use of the sessile drop test as a pre-bond inspection tool for bonded composite repairs was investigated. A portable goniometer suitable for a maintenance workshop in the aviation industry was designed and built. Dimethyl sulfoxide and water were used as testing fluids, dispensed in 3 μl quantities. Contact angles were measured using the spherical approximation for a range of surfaces which included samples that had been peel-plied, hand sanded, grit blasted and contaminated with silicone release agent. The surface energies of the samples were then evaluated using the Owens-Wendt and Girifalco-Good-Fowkes-Young (GGFY) methods. Although the GGFY method successfully distinguished contamination, difficulties arose when evaluating surface roughness. Peel-ply surfaces also had varying contact angles due to irregular droplet shapes. The Owens-Wendt method was also found to be inaccurate with only two test fluids although this is regarded as industry standard, It is for these reasons that traditional surface energy methods were considered impractical for a workshop environment. An alternate measurement parameter considered was the droplet diameter where the same testing fluids were imaged from the top instead. This measurement successfully differentiated contamination and also allowed the abrasion process to be determined. In addition, the degree of abrasion could be determined between grit blasted and untreated peel-ply surfaces. This test was found to be more accurate than the traditional surface energy techniques and has the potential to form part of a pre-bond surface certification process for bonded composite repairs.
Keyword Composite adhesive bonding
Pre-bond inspection
Quality assurance
Surface testing
Surface energy
Q-Index Code E1
Q-Index Status Confirmed Code
Institutional Status UQ

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Created: Wed, 27 Mar 2013, 12:48:21 EST by Mr Edmund Liew on behalf of School of Mechanical and Mining Engineering