Dual Mode Sensing with Low-Profile Piezoelectric Thin Wafer Sensors for Steel Bridge Crack Detection and Diagnosis

<table>0.5 mm PLB detection on 1.6-mm aluminum plate. (a) PWAS AE waveform and its frequency spectrum; (a) R15I AE waveform and its frequency spectrum.</table>

Advances in Civil Engineering

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Figure 4

Figure 4: Dual Mode Sensing with Low-Profile Piezoelectric Thin Wafer Sensors for Steel Bridge Crack Detection and Diagnosis 