  Ultrasonic guided waves offer a convenient and practical approach to
structural health monitoring and non-destructive evaluation. A key property of
guided waves is the fully-defined relationship between central frequency and
propagation characteristics (phase velocity, group velocity and wavenumber) --
which is described using dispersion curves. For many guided wave-based
strategies, accurate dispersion curve information is invaluable, such as group
velocity for localisation. From experimental observations of dispersion curves,
a system identification procedure can be used to determine the governing
material properties. As well as returning an estimated value, it is useful to
determine the distribution of these properties based on measured data. A method
of simulating samples from these distributions is to use the iterative
Markov-Chain Monte Carlo (MCMC) procedure, which allows for freedom in the
shape of the posterior. In this work, a scanning-laser doppler vibrometer is
used to record the propagation of Lamb waves in a unidirectional-glass-fibre
composite plate, and dispersion curve data for various propagation angles are
extracted. Using these measured dispersion curve data, the MCMC sampling
procedure is performed to provide a Bayesian approach to determining the
dispersion curve information for an arbitrary plate.
