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Inspired by an innovative sensing philosophy, a lightweight nanocomposite sensor made of a hybrid of carbon black (CB)/polyvinylidene fluoride (PVDF) was developed. The nanoscalar architecture and percolation characteristics of the hybrid were optimized, in order to fulfil in-situ acquisition of dynamic elastic disturbance from low-frequency vibration to high-frequency ultrasonic waves. Dynamic particulate motion induced by elastic disturbance modulates the infrastructure of CB conductive network in the sensor, with introduction of the tunneling effect, leading to dynamic alteration in piezoresistivity measured by the sensor.Electrical analysis, morphological characterization, and static/dynamic electro-mechanical response interrogation were implemented, to advance insight into the sensing mechanism of the sensor, and meanwhile to facilitate ascertainment of an optimal percolation threshold. At the optimal threshold (~ 6.5 wt%), the sensor exhibits high-fidelity, fast-response, and highsensitivity to ultrafast elastic disturbance (in an ultrasonic regime up to 400 kHz) yet with an ultralow magnitude (of the order of micrometer). Performance of the sensor was evaluated, against conventional piezoelectric transducer and strain gauge, showing excellent coincidence, yet a much greater gauge factor and frequency-independent piezoresistive behaviours. Coatable to a structure and deployable in a large quantity to form a dense sensor network, this nanocomposite sensor has blazed a trail for implementing in-situ sensing for vibration-or ultrasonic wave-based structural health monitoring, by striking a compromise between "sensing cost" and "sensing effectiveness".

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