MESOSCALE HOMOGENIZATION NUMERICAL STUDY ON THE SIGNIFICANCE OF CONCRETE MESOSCALE STRUCTURE ON WAVE PROPAGATION OF RECTANGULAR RCFSTS WITH DEBONDING

Abstract

In this paper, in order to efficiently distinguish the influence of both interface debonding defect and the mesoscale structure of concrete core on the stress wave field and the response of an embedded Piezoelectric-lead-zirconate-titanate (PZT) sensor in rectangular concrete filled steel tube (RCFST) members, a two dimensional (2D) mesoscale numerical concrete with homogenization approach considering the random distribution of circle, ellipse and irregular polygon aggregates is proposed firstly. Then, mesoscale homogenization simulation on stress wave fields within the cross-sections of RCFST members with and without interface debonding defects are carried out, respectively. The effect of both mesoscale structure of concrete core and the interface debonding defect on the stress wave field of each member is discussed. Therefore, the time-domain response of the embedded PZT sensor in the RCFST members coupled with PZT patches under sweep frequency excitation signal is determined and compared when both mesoscale models and their homogenization models are used. The sensitivity of the wavelet packet energy of the embedded PZT sensor response on the variation of both mesoscale structure of concrete core and the dimension of interface debonding defects is investigated. The detectability of interface debonding using stress wave measurement is illustrated efficiently with the proposed mesoscale homogenization modelling approach even the mesoscale structure of the concrete core is considered.