Quantitative evaluation of fracture processes in concrete using signal-based acoustic emission techniques

Abstract

Acoustic emission (AE) techniques can be used for the investigation of local damage in materials.Compared to other observation techniques one advantage is the recording of the damage process during the entire load history without any disturbance to the specimen. This is somehow unique and permits for high-resolution studies of the time dependend failure of materials including precise determinations of the beginning of fractures and their consecutive progression. There are only a few other experimental techniques in fracture mechanics allowing for similar detailed observations of materials' time and spatial behaviour. Moreover, these techniques allow a calibration of experiment and simulation comparing for example the output of Finite ElementModelling with AE data analysis. This paper deals with some experimental results obtained during fracture mechanical experiments at concrete specimens demonstrating the capabilities of quantitative AE techniques.

Characterisation of Al corrosion and its impact on the mechanical performance of composite cement wasteforms by the acoustic emission technique

“…These factors determine the complexity of the experimental setup and the repeatability of the results obtained. Therefore a strict correlation between dimensional indications obtained by the detected AE waves and the nature of the failure process can be determined based on relatively complicate data interpretation methods including advanced signal processing, e.g., wavelet and moment tensor analysis [11][12][13]. However, the information gained from defects growth, onset of new microfracture patterns and their dynamics, especially in cement-based structures, supply useful elements for a diagnosis of the degradation phenomena in progress [14][15][16][17][18][19][20].…”

“…Signal parameter-based analysis is a conventional approach for AE sources characterisation and overall assessment of the mechanical performance of materials and structures [9,12]. It is suitable for less time and storage consuming data acquisition applications, e.g., monitoring and inspection of large concrete bridges, pressure vessels and oil tanks.…”

Nondestructive Evaluation of Welding Crack Defects in Structural Component Of Track Crane Using Acoustic Emission Technique

“…(c) It can even detect the growth of subsurface cracks even before it appears on the surface, which is one of the advantages of AE technology over the well established vibration analysis [6]. (d) AE monitoring has an added advantage that it can record the damage process including precise determinations of the beginning of fractures and their consecutive progression during the entire load history without any disturbance to the specimen [7]. AE technique is, therefore, widely used in nondestructive testing for the detection of crack propagation and failure detection in metal materials.…”

“…Compared to other observation techniques, AE technology has some of the principal advantages: (a) since AE is produced at microscopic level it is highly sensitive and offers opportunities for identifying defects at an earlier stage when compared to other monitoring techniques. (b) As AE only detects highfrequency elastic waves, it is insensitive to structural resonances and typical mechanical background noise [5]. (c) It can even detect the growth of subsurface cracks even before it appears on the surface, which is one of the advantages of AE technology over the well established vibration analysis [6].…”

“…However, damage and failure processes often generate several thousand events from one damage zone within a very short time interval, revealing a huge amount of data [8]. As numerous AE signals can occur during a nondestructive test, a variable which can represent the features of the AE signals is used in AE signal processing.…”