Waveform Analysis of Acoustic Emission in Concrete

Abstract

In order to utilize AE phenomena in materials research and for nondestructive testings, considerable basic studies are urgently required in order to clarify the physical meanings of AE signals. For this end, extensive studies in correlations between AE parameters and mechanical behaviors of concrete materials and structures have been carried out in our research. In this paper, some of our recent developments on AE waveform analysis are described. In searching for the source mechanisms of AE, the aim of waveform analysis may be to separate the effects of the propagation media and the transducers from the detected AE waveforms, and to determine the kinetic and kinematic characteristics of sources. Therefore, the deconvolution techniques in both the time domain and the frequency domain are developed. They have been applied to investigate two basic types of sources, namely, a point force and a tensile crack. Results show that our original notions concerning the source mechanisms of AE, which can be mathematically described by the dislocation model, are acceptable. The applicability of elastodynamics and the dislocation theory for studying the relation between the source mechanisms and wave motions of AE is also verified.