Structural damage detection and
localization by non-linear acoustic spectroscopy
Dr. Gerard Vanderborck,
Thales Underwater Systems
Dr. Bernard Rousselet,
Abstract:
The strong linkage between damage and nonlinear elasticity of materials
leads to many researches in the field of nonlinear response of mechanical
structures .
Due to severe mechanical environment conditions ( Vibration,
Shock…), damage may appear in structures. In a previous S&V symposium we
have presented some interesting experiments who have shown that non linear
acoustic spectroscopy is be a very powerful technique in order to detect damage
in structures
The proposed method consists of the observation of
nonlinear responses obtained from an array of sensors when the structure
is excited by dual frequency sources : the low frequency source yields the
power while the second acts as a probe . The nonlinear response is obtained by
spectral analysis of signals coming from sensors , the
response amplitude is proportional to the local nonlinearity (failure nonlinear
elastic response) .
Now we have developed the theoretical and mathematical approach of the problem
and we show a good correlation between the modeling and the experiment.
We explain also the ideas that are behind the concept of localization of
damage.
We also show that this technique based on non linear acoustic is a good concept
in order to detect buried objects.
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