The parameters and spectra of acoustic-emission signals that arise during the inspection of precast concrete structures are studied. The information content of these parameters is discussed in terms of flaws that develop in structures subjected to stresses.The acoustic-emission (AE) technique has been used increasingly for diagnostics of pressure vessels, pipelines, components of machines and mechanisms, and for forecasting outbursts in coal mines. A new generation of acoustic-emission systems has been developed that are capable of detecting and processing the information obtained in real time. The informational content of the parameters of detected AE signals still remains a topic of interest. This work involves discussion of the results of a study that is concerned with, on the one hand, the relationship between a number of parameters and the spectra of AE signals and, on the other hand, the processes of deformation and fracture of precast concrete structures.The experiments were conducted on concrete beams. These beams were made from a heavy concrete of the Ç 25 class of compressional strength. They had the following geometric dimensions: 2200 mm in length, 290 mm in height, and 160 mm in width. The beams were reinforced by two 16-mm-diameter reinforcing rods of the AtV class. The beam's reinforcing elements were pretensioned by the method of mechanical stretching on abutments. Two beams were tested; they differed from each other by their values of reinforcement pretensioning: the value of pretensioning was 60 kN in beam 1 and 110 kN in beam 2. A concrete beam was loaded with a hydraulic jack and with a manual hydraulic pumping station. The load transmitted from the hydraulic set to the concrete beam through a stiffening distributing beam was concentrated in two points at a distance of 670 mm from the beam's ends. Two hinged bearers were used to support the beams. The distance from the beam ends to the bearings was 150 mm. The beams were loaded stepwise.After each stage of loading, the deflection of the beam was measured, cracks were detected, and their lengths and openings were measured. If a crack which already existed "grew further" at the next stage of loading, this increment was detected and measured. All lengths of the cracks detected at the stages of the testing were summarized. The total length of the cracks measured in the experiments was then used to analyze the informativeness of the AE signals' parameters.The deflections of the structures were measured in the centers of the concrete beams using deflectometers with a scale value of 0.01 mm.The acoustic-emission measurements were carried out using an A-Line 32D series (ISA) eight-channel digital AE system. The acoustic-emission instrument was manufactured by OOO Interyunis (Moscow). The A-Line 32D system is a multichannel system intended for gathering and processing acoustic-emission information obtained by acoustic-emission probing of the structure studied during the experiment.AE detectors were arranged on three planes of the beams' surfaces. To lo...
Acoustic emission (AE) techniques are extensively applied to a variety of fields
including civil engineering. Now a new generation of AE techniques, which are able to register and
process AE data in real-time, has appeared. Still, there exist some problems to correctly interpreting
these data and to completely understand the meaning of AE parameters. In order to solve this,
several AE waveform and spectral parameters are investigated, based on an experimental study of
concrete and reinforced concrete structures.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.