bender elements

1
Bender elements, wave propagation in soil samples
and results interpretation

• Objectives of the Presentation
• Compare time domain results interpretation with
  frequency domain signal processing.

IS Lyon 03 - workshop on current practises of the
use of bender element technique
João Filipe Rio - University College London
2
Bender elements, wave propagation in soil samples
and results interpretation
Frequency Domain
Phase-frequency variation Discrete or continuous
Transfer Function approach. Indirect
determination of travel time. But takes all of
the input and output signals into
consideration. The results show further signs of
dispersion, casting more doubts about the time
analysis.
figure 1 pulse signals transfer function,
discrete pi point and correspondent best fit
lines.
IS Lyon 03 - workshop on current practises of the
use of bender element technique
João Filipe Rio - University College London
3
Bender elements, wave propagation in soil samples
and results interpretation
Frequency Domain
Different signals types. The three received
signals are apparently different. But they
produce the same TF arrival time. This results
are coherent with the discrete frequency analysis
(pi points).
figure 2 3 different types of input signal and
correspondent
IS Lyon 03 - workshop on current practises of the
use of bender element technique
João Filipe Rio - University College London
4
(No Transcript)
5
(No Transcript)
6
(No Transcript)
7
(No Transcript)