Comparative Assessment and Experimental Validation of a Prototype Phase-Optical Time-Domain Reflectometer for Distributed Structural Health Monitoring

Figure 13

The frequencies of the bridge response to different excitation conditions, revealed by the four monitoring systems (PO: Phase-OTDR). Green frequencies are expected to be revealed because they correspond to the excitation frequency. Red frequencies appear only for some, and not all, monitoring technologies. First six graphs have a frequency axis compressed in two points before and after 50 Hz to allow their inline pair fitting.

(a)

(b)

(c)

(d)

(e)

(f)

(g)