Abstract For the detection of delaminations in thin multilayered composite plates, two different techniques based on the processing of band-limited ultrasonic pulses reflected from the sample under investigation are presented. The first technique exploits the differences between the signals reflected from the flawless and delaminated regions, which are revealed using the modified iterative L1 norm deconvolution. From filtered A-scans, two-dimensional C-type scans are produced in two different ways. The second technique is based on a spectroscopic analysis of the differential signature of a sample, which is obtained by subtracting from the reference signal, reflected by a flawless region, the pulse received at any arbitrary point and presentation of two-dimensional images at various frequencies. The experimental results indicate that both techniques enable one to determine between which layers delamination took place.
[1]
N. R. Chapman,et al.
Comparison of the l 1 and l 2 norms applied to one-at-a-time spike extraction from seismic traces
,
1984
.
[2]
Richard W. Martin,et al.
Applications of Digital Image Enhancement Techniques to the Ultrasonic NDE of Composite Materials
,
1987
.
[3]
J. Szilard,et al.
Ultrasonic testing: Non-conventional testing techniques
,
1982
.
[4]
R. E. Challis,et al.
Ultrasonic compression wave propagation in adhesive polymers described as a signal filtering process
,
1995
.
[5]
NDE in Multilayers: Theory, Computer Simulation and Experiments
,
1987
.