Recent projects

Ultrasonic Non-destructive Evaluation and Guided Waves

We have developed methodology in several areas of wave modelling, oriented around ultrasonic inspection including novel absorbing layer techniques [3] and hybrid methods (with Rolls-Royce and the French Atomic Energy Commission amongst others) for Finite Element (FE) software [4], and efficient techniques for finding the properties of waves in curved plates, bars and pipes [2,5]. We have systematically attacked the bottlenecks in wave simulation for ultrasonics by developing hybrid methods (to speed up simulations when defect and receiver are separated by large distance) and absorbing boundaries (to prevent unwanted reflections from computational boundaries). Pieces of the modelling work outlined above formed an impact case for REF 2014.

Characterizing cracks within elastic media forms an important aspect of ultrasonic non-destructive evaluation where techniques such as time-of-flight diffraction and pulse-echo are often used with the presumption of scattering from smooth, straight cracks. However, cracks are rarely straight, or smooth, and recently we have turned our attention to focus upon rough surface scattering. We have provided comprehensive studies of scattering by incident shear and compressional waves using modelling, simulation and supporting experiments, see for instance [1].

This work is performed with colleagues from the NDE group from Mechanical Engineering at Imperial College, Mike Lowe and Peter Huthwaite, and is joint work with many PhD students and postdoctoral researchers some of whom are in the references below.

Selected references
  1. F. Shi, M. J. S. Lowe, X. Xi and R. V. Craster, ``Diffuse scattered field of elastic waves from randomly rough surfaces using an analytical Kirchhoff theory'' J. Mech. Phys. Solids., 92, 260--277, 2016. Available here
  2. F. Hernando Quintanilla, M. J. S. Lowe and R. V. Craster ``Full 3D Dispersion Curve Solutions for Guided Waves in Generally Anisotropic Media'' J. Sound Vib., 363, 545--559, 2015 Available here
  3. P. Rajagopal, M. Drozdz, E. Skelton, M.J.S. Lowe and R.V. Craster, “On the use of absorbing layers to simulate the propagation of elastic waves in unbounded media using commercially available Finite Element packages”, NDT and E International, 51, 30-40 (2012) Available here
  4. W. Choi, E. A. Skelton, J. Pettit, M. J. S. Lowe and R. V. Craster, ``A generic hybrid model: Three-dimensional bulk elastodynamics in non-destructive evaluation'' IEEE Trans. Ultrasonics, Ferroelectrics and Frequency Control 63, 726--736, 2016 Available here
  5. A.T.I. Adamou and R.V. Craster, “Spectral methods for modelling guided waves in elastic media'', J. Acoust. Soc. Am. 116, 1524-1535 (2004) Available here