Dominance of debonding defect of CFST on PZT sensor response considering the meso-scale structure of concrete with multi-scale simulation

Multi-Scale Stress Wave Simulation for Aggregates Segregation Detection of Concrete Core in Circular CFST Coupled with PZT Patches

“…The numerical concrete sample generating procedure has been reported in detail [ 13 ]. The program for the generation of random aggregates in concrete cubes is similar to that for CFST structures, which is excluded herein.…”

“…After establishing the multi-scale models of CCFST based on the random aggregate generation program, finite element meshing is performed with the multi-physical analysis software COMSOL as a solver. The dynamic equation of piezoelectric ceramics and the circuit state equation are described in Equations (3) and (4) [ 11 , 13 , 31 ]: where [ M ] is the general mass matrix, [ K ] stands for the stiffness matrix, { F } represents the load vector, V and Q are the electric potential on the electrode surface and the electricity of free charge, C 0 is the clamp fixed capacitors, { P } is the electromechanical coupling vector, and { u } denotes the system displacement vector. Equation (5) shows the governing equations of the piezoelectric coupling system in the form of the generalized matrices and vectors.…”

“…Even though several NDT technologies are available for the damage detection and condition monitoring for reinforced concrete (RC) structures and concrete–steel composite structures, efficient concrete aggregate segregation detection for CFST members is still a challenging task [ 7 ]. Even though some NDT techniques, such as the ultrasonic method, acoustic emission, infrared thermography, electromagnetic method, X-ray, and radar/microwave approaches, have been widely employed in structural health monitoring (SHM), no efficient methods have been proposed for the inspection and monitoring of the concrete aggregate segregation in CFST members [ 8 , 9 , 10 , 11 , 12 , 13 ]. Until now, available on-site concrete aggregate segregation assessment methods are extremely limited [ 14 ].…”

“…Experimental observations showed that the defined evaluation indices based on wavelet packet energy or the wavelet packet energy spectrum were sensitive to the interface debonding defect [ 8 , 9 ]. Recently, Xu et al performed numerical studies on the stress wave propagation characteristics in both circular and rectangular CFST members where the concrete core is simulated with homogeneous material assumption [ 10 , 11 , 12 , 13 ].…”

Numerical Study of Concrete Mesostructure Effect on Lamb Wave Propagation

“…Although the papers published by Xu et al [ 17 ], Abo-Quadis [ 18 ], and Ramaniraka et al [ 19 ] deal with the impact of the concrete mesostructure on waves characteristics, the problem of wave propagation in heterogeneous materials is still not considered in detail, yet. The existence of aggregates varying in size, shape, and material parameters, and pores and cracks may lead to additional disturbing phenomena like scattering, diffractions, and wave attenuation affecting wave amplitude or propagation velocity, which were commonly used as indicative parameters in the above-mentioned studies.…”