A novel embeddable spherical smart aggregate for structural health monitoring: part I. Fabrication and electrical characterization

Abstract

Recently developed piezoceramic-based transducers, known as smart aggregates (SAs), have shown their applicability and versatility in various applications of structural health monitoring (SHM). The lead zirconate titanate (PZT) patches embedded inside SAs have different modes that are more suitable for generating or receiving different types of stress waves (e.g. P and S waves, each of which has a unique role in SHM). However, due to the geometry of the 2D PZT patch, the embedded SA can only generate or receive the stress wave in a single direction and thus greatly limits its applications. This paper is the first of a series of two companion papers that introduces the authors’ latest work in developing a novel, embeddable spherical smart aggregate (SSA) for the health monitoring of concrete structures. In addition to the 1D guided wave produced by SA, the SSA embedded in concrete structures can generate or receive omni-directional stress waves that can significantly improve the detection aperture and provide additional functionalities in SHM. In the first paper (Part I), the detailed fabrication procedures with the help of 3D printing technology and electrical characterization of the proposed SSA is presented. The natural frequencies of the SSA were experimentally obtained and further compared with the numerical results. In addition, the influence of the components’ thickness (spherical piezoceramic shell and epoxy) and outer radius (spherical piezoceramic shell and protection concrete) on the natural frequencies of the SSA were analytically studied. The results will help elucidate the key parameters that determine the natural frequencies of the SSA. The natural frequencies of the SSA can thus be designed for suitability in the damage detection of concrete structures. In the second paper (Part II), further numerical and experimental verifications on the performance of the proposed SSA in concrete structures will be discussed.

Study on Seismic Performance and Damage Analysis of Steel Plate Shear Wall with Partially Encased Composite (PEC) Columns

“…As the enanbling element for the active sensing method [57][58][59] and the electromechanial impedance (EMI) method [60,61], PZT transducers are often used in structural health monitoring (SHM) systems [62][63][64][65][66]. With the recent development of PZT based smart aggregates in concrete structure damage detection [67][68][69][70][71] and the application of PZT transducers in health monitoring of steel-concrete composite structures [72][73][74][75], the authors will explore health monitoring and damage detection of steel plate shear wall with PEC Columns using the embeddable smart aggregates [76,77] and the easy-to-install surface-bonded piezoceramic patch transducers [78] in the future work.…”

Detecting Debonding between Steel Beam and Reinforcing CFRP Plate Using Active Sensing with Removable PZT-Based Transducers

“…Because of the piezoelectricity effect, a PZT patch can be used as either a sensor or an actuator [51], and a PZT patch can generate and detect stress waves [34,42,52]. Traditionally, a PZT patch can be embedded inside a structure or bonded to a structural surface to conveniently enable the active sensing approach [53][54][55]. To detect debonding damages at different locations, a removable PZT transducer was developed in this research.…”

Detecting of the Longitudinal Grouting Quality in Prestressed Curved Tendon Duct Using Piezoceramic Transducers

“…Among various piezoceramic materials, lead zirconate titanate (PZT) has the strongest piezoelectric effect and can be fabricated in different shapes [39,40]. With proper protection, various PZT based transducers that are suitable for deployment in civil structures, including the concrete structures, have been developed [41][42][43][44], and have found application in bridge structural health monitoring [45][46][47]. The active sensing method based on piezoceramic transducers is to bond PZT transducers on the surface of structure [48] or embed piezoelectric transducers in the structure [49], and then the actuator generates the signals, which is detected by the sensors.…”