Welcome
to
this webpage (available only in English) containing information about my
research and PhD thesis.
The PhD thesis on Defect detection in plates using guided
waves was accepted in 2001 on the recommendation of Prof. Dr. M.B. Sayir
(examiner), Prof. Dr. P. Cawley (coexaminer), and Prof. Dr. S.K. Datta
(coexaminer).
On the next few pages you can find a short summary of my PhD
thesis, the application of the developed NDT method for the detection and
monitoring of fatigue cracks in aerospace structures, and further information on
my research. The complete thesis is available from ETH library using the
following link:
P. Fromme
Defect detection in plates using guided waves
PhD thesis, Diss ETH No. 14397 (2001)
Electronic Link:
http://e-collection.ethbib.ethz.ch/cgi-bin/show.pl?type=diss&nr=14397
PhD
Thesis
Abstract
This dissertation deals with the propagation and scattering
of guided waves in plates for the nondestructive testing (NDT) of aerospace
structures.
Guided waves have the advantage of propagating over large distances, thus
allowing the fast and efficient detection of defects in large structures. The
specific problem studied is the detection of fatigue cracks at rivet and
fastener holes in aluminum sheets, as used in aircraft fuselage and wings.
Employing the first antisymmetric Lamb wave mode A0, the scattering at a hole
with a defect is investigated experimentally and theoretically. The guided
flexural wave is excited selectively by means of a piezoelectric transducer and
measured using a heterodyne laser interferometer. The scattered field around the
obstacle is calculated analytically using Mindlin's theory and numerically
implementing a finite difference algorithm. Good agreement between the
experimental data and the theoretical calculations is found, allowing a
prediction of the detectability of small defects. An on-line monitoring of
fatigue crack growth during tensile testing is implemented in collaboration with
an industrial partner and found to give repeatable results. The minimum
detectable crack length is evaluated and the practical applicability of the
method shown.
Current Research
And where I'd rather
be:
