This is a joint project with Prof Tony Kinloch of The Materials Section in the Mechanical Engineering Department at Imperial College. Degradation of the interlayer between the adhesive and the adherend caused by environmental attack is one of the most common causes of failure in joints and is particularly difficult to detect since the interlayer is often only about 1µm thick. This project is investigating the use of ultrasonic reflection methods at both normal and oblique incidence to detect the onset of attack, and also aims to clarify the mechanism(s) by which the attack progresses.
References
Pialucha, T.P. and Cawley, P. 'An investigation of the accuracy of oblique incidence ultrasonic reflection coefficient measurements', J Acoust Soc Am, Vol 96, pp1651-1660, 1994.
Pialucha, T.P. and Cawley, P. 'The detection of thin embedded layers using normal incidence ultrasound', Ultrasonics, Vol 32, pp431-440, 1994.
Cawley, P., Pialucha, T.P. and Zeller, B.D. 'The characterisation of oxide layers in adhesive joints using ultrasonic reflection measurements', Proc Royal Soc Lond, Series A, Vol 452, pp1903-1926, 1996.
Vine, K., Cawley, P. and Kinloch, A.J. 'The correlation of non-destructive measurements and toughness changes in adhesive joints during environmental attack', J Adhesion, Vol 77, pp125-161, 2001.
Vine, K., Cawley, P. and Kinloch, A.J. 'Comparison of normal and oblique incidence ultrasonic measurements for the detection of environmental degradation of adhesive joints', NDT&E International, Vol 35, pp241-253, 2002.
M J S Lowe, R E Challis, C W Chan, "The Transmission of Lamb Waves Across Adhesively Bonded Lap Joints", J. Acoust. Soc. Am., vol. 107, pp.1333-1345, 2000.
T Vogt, M J S Lowe, P Cawley, "Cure monitoring using ultrasonic guided waves in wires", J.Acoust. Soc. Am., vol 114, pp.1303-1313, 2003.