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370 IDT MICROSENSORS
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Figure 13.10 Experimental results of a strain guage SAW-IDT sensor
Original beam
Extended beam
Figure 13.11 Test setup for dynamic strain sensing
The dynamic variation of the strain in the vibrating beam was measured by the use
of a wireless passive detector. The results are presented in Figure 13.12. The surface
strain of the beam was found to vary periodically corresponding to the vibration time
period of 1.4 second and decayed because of damping effects. The initial maximum
strain was found to be —1100 microstrains, which agrees with the calculated value of
strain. The sensor wirelessly measured the strain caused by both the static and dynamic
loads.
