Flexible 1–3 Composite Ultrasound Transducers With Silver-Nanowire-Based Stretchable Electrodes

A Phased Array Ultrasound Roller Probe for Automated in-Process/Interpass Inspection of Multipass Welds

“…Although there are solid high temperature (HT) wedge assemblies commercially available, which could be used to perform discrete manual inspections at temperatures up to 300 °C for a very limited period of time [12], they lack the ability to perform continuous automated scans especially over curved or complex geometries. Also, fixed geometries of these HT wedges can restrict the application to the inspection of components with specific structural shapes [13].…”

Micro‐Structuration of Piezoelectric Composites Using Dielectrophoresis: Toward Application in Condition Monitoring of Bearings

“…Piezoelectric materials—because of their ability to translate a mechanical impulse into an electric response—are commonly used as sensors in vibration monitoring, impact detection, and ultrasonic receiving sensors. [ 2,6–14 ] There are different classes of piezoelectric materials, such as ferroelectric ceramics [BaTiO 3 , lead zirconate titanate (PZT)], piezoelectric polymers [polyvinylidene fluoride (PVDF), poly(vinylidene fluoride‐trifluoroethylene) (P(VDF‐TrFE))], and piezoelectric composites that are made of ferroelectric ceramic filler embedded in the polymer matrix. [ 9,14–22 ] Piezoelectric composites are undoubtedly the most suitable materials for this application: they are able to combine the piezoelectric properties of the filler with the flexibility of the matrix, which makes them preferable relative to bulk ceramic.…”

“…Indeed, the connectivity of the filler controls the distribution of the electric flow in the material. [ 11,28–30 ] Composites with 0–3 connectivity, which consist of homogeneously dispersed particles in the matrix, are the most commonly produced because of their simple fabrication. [ 22,30,31 ] Nevertheless, they exhibit low piezoelectric sensibility until they reach large volumetric contents.…”

“…In this anisotropic structure, called 1–3, the particles are closely aligned along the preferred direction, giving rise to enhanced piezoelectric properties of the whole material. [ 11,12,32,33 ]…”

“…Nowadays, piezoelectric composites are widely exploited in the health monitoring system of structural components. [ 11,12,29 ] A smart‐coated piezoelectric sensor made of PZT/PDMS composite, directly placed on the component, might represent one of the best solutions to perform direct in situ monitoring of ball bearing conditions.…”