The objective of this project is to develop Finite Element modelling procedures for simulating the interaction of ultrasound with defects in structures. Currently the capabilities are limited by a maximum model size such that cracks and corrosion defects have to be idealised by very simple shapes. The project will develop two topics to achieve a step improvement in capability: (a) improved non-reflecting model boundaries, enabling a much smaller local region of the structure to be studied; (b) new methods for numerical representation of the defect region, enabling true shapes to be modelled accurately.

References

M J S Lowe, O Diligent, "The low frequency reflection characteristics of the fundamental symmetric Lamb wave S0 from a rectangular notch in a plate", J.Acoust. Soc. Am., vol. 111, pp. 64-74, 2002.

O Diligent, T Grahn, A Bostrom, P Cawley, M J S Lowe, "The low frequency reflection and scattering of the S0 Lamb mode from a circular through-thickness hole in a plate: Finite Element, analytical and experimental studies", J.Acoust. Soc. Am., vol 112, pp. 2589-2601, 2002.

A Demma, P Cawley, M J S Lowe, "Scattering of the fundamental SH mode from steps and notches in plates", J.Acoust. Soc. Am., vol. 113, pp. 1880-1891, 2003.

M J S Lowe, P Cawley, J-Y Kao, O Diligent, "The low frequency reflection characteristics of the fundamental anti-symmetric Lamb wave A0 from a rectangular notch in a plate", J.Acoust. Soc. Am., vol 112, pp. 2612-2622, 2002.

O Diligent, M J S Lowe, "Reflection of the S0 Lamb mode from a flat-bottomed circular hole", J.Acoust. Soc. Am., vol. 118, pp. 2869-2879, 2005.

P Rajagopal, MJS Lowe, "Short range scattering of the fundamental shear horizontal guided wave mode normally incident at a through-thickness crack in an isotropic plate", J. Acoust. Soc. Am., vol. 122, 1527-1538, 2007.

P Rajagopal, MJS Lowe, "Scattering of the fundamental shear horizontal guided wave mode by a part-thickness crack in an isotropic plate", J. Acoust. Soc. Am., vol. 124, 2895-2904, 2008.

P Rajagopal, MJS Lowe, "Angular influence on scattering when the fundamental shear horizontal guided wave mode is incident at a through-thickness crack in an isotropic plate", J. Acoust. Soc. Am., vol. 124, 2021-2030, 2008.

M Ratassepp, MJS Lowe, P Cawley, A Klauson "Scattering of the fundamental shear horizontal mode in a plate when incident at a through-crack aligned in the propagation direction of the mode", J. Acoust. Soc. Am., vol 124, 2873-2882, 2008.