Ultrasound tomography for health monitoring of carbon fibre–reinforced polymers using implanted nanocomposite sensor networks and enhanced reconstruction algorithm for the probabilistic inspection of damage imaging

Abstract

Irrespective of the popularity and demonstrated effectiveness of ultrasound tomography (UT) for damage evaluation, reconstruction of a precise tomographic image can only be guaranteed when a dense transducer network is used. However, a network using transducers such as piezoelectric wafers integrated with the structure under inspection unavoidably lowers local material strength and consequently degrades structural integrity. With this motivation, an implantable, nanocomposite-inspired, piezoresistive sensor network is developed for implementing in situ UT-based structural health monitoring of carbon fibre–reinforced polymer (CFRP) laminates. Individual sensors in the network are formulated with graphene nanosheets and polyvinylpyrrolidone, fabricated using a spray deposition process and circuited via highly conductive carbon nanotube fibres as wires, to form a dense sensor network. Sensors faithfully respond to ultrasound signals of megahertz. With ignorable intrusion to the host composites, the implanted sensor network, in conjunction with a UT approach that is enhanced by a revamped reconstruction algorithm for the probabilistic inspection of damage–based imaging algorithm, has proven capability of accurately imaging anomaly in CFRP laminates and continuously monitoring structural health status, while not at the cost of sacrificing the composites’ original integrity.

Embedded Sensors for Structural Health Monitoring: Methodologies and Applications Review

“…A new breed of implanted nanocomposite sensor network has been developed for implementing an in situ, ultrasound tomography-driven SHM of carbon fibre-reinforced polymer (CFRP) laminates. Individual sensing units were formulated with graphene nanosheets using a spray deposition process, circuited with highly conductive carbon nanotube fibres as wires, and then implanted into CFRP laminates to form a dense sensor network [ 115 ]. Monitoring the moisture content inside the concrete structure is one of the most critical factors to ensure structural integrity.…”

“…Currently, it is possible to obtain enough types of composite materials; accordingly, a set of techniques for the processing and manufacture of composite materials has been developed, which can be divided into several typologies. Among them exist open moulding (Figure 10a), resin infusion processes (Figure 10b), and high-volume moulding methods, such as automated fibre placement (Figure 10c), compression moulding (Figure 10d) [125][126][127], and spray deposition processes [115]. Based on the existing technological processes for the manufacture of composite materials, there are already studies that have experimentally validated the use of embedded sensors in composite materials.…”

Embedded Sensors for Structural Health Monitoring: Methodologies and Applications Review

“…A new breed of implanted nanocomposite sensor network was developed, for implementing in situ, ultrasound tomography driven SHM of carbon fibre-reinforced polymer (CFRP) laminates. Individual sensing units are formulated with graphene nanosheets using a spray deposition process, circuited with highly conductive carbon nanotube fibres as wires and then implanted into CFRP laminates to form a dense sensor network [117].Monitoring the moisture content inside concrete structure is one of the most critical factors to ensure structural integrity. However, much of the equipment or technologies used to measure moisture content are destructive and require additional drilling in the material to perform a measurement.…”

“…Currently, it is possible to obtain enough types of composite materials, for this, a set of techniques of processing and manufacture of composite materials have been developed, that can be divided into several typologies. Among them exist open moulding (Figure 10 a) ), resin infusion processes (Figure 10 b) ) and high-volume moulding methods, such as automated fibre placement (Figure 10 c) ), compression moulding (Figure 10 d)) [127][128][129] and spray deposition processes [117].…”

Sparse Array (Nonlinear) Guided Wave Imaging for Localization of Damage in Composites

“…After that, several advanced techniques were utilized to improve the accuracy and robustness of this method, e.g. nanocomposite sensors [5], l p norm approach [6], and fused damage index [7][8]. Besides, the modification of key parameters in RAPID improved the damage sizing accuracy [9][10].…”