Acoustic emission

About: Acoustic emission is a research topic. Over the lifetime, 16293 publications have been published within this topic receiving 211456 citations.

Acoustic emission source location in composite materials using Delta T Mapping

Abstract: The location capability of the acoustic emission (AE) technique is often considered its most powerful attribute. However, assumptions made in the calculation of location by current algorithms can be limiting in complex geometries and materials. This work forms a detailed study into the use of a novel mapping technique for AE source location in fibre reinforced composite materials. Both the performance and the robustness of the approach are assessed using artificial and real AE sources. Furthermore a large fatigue specimen was used to demonstrate detection and location of damage onset and development, where findings were validated using a thermo-elastic stress analysis (TSA) system. Substantial improvements in location accuracy were observed and early detection of damage onset was seen to outperform TSA.

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-dependent 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 element modelling 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.

Simulation of Acoustic Emission in Planar Carbon Fiber Reinforced Plastic Specimens

Abstract: The simulation of acoustic emission waveforms resulting from failure during mechanical loading of carbon fiber reinforced plastic structures is investigated using a finite element simulation approach. For this investigation we focus on the dominant failure mechanisms in fiber reinforced structures consisting of matrix cracking, fiber breakage and fiber-matrix interface failure. To simulate the failure process accurately, we present a new acoustic emission source model that is based on the microscopic source geometry and micromechanical properties of fiber and resin. We demonstrate that based on this microscopic source model these failure mechanisms result in excitation of macroscopic plate waves. The propagation of these plate waves is described using a macroscopic three-dimensional model geometry which includes contributions of reflections from the specimen boundaries. We further present a model of the acoustic emission sensors used in experiments to simulate the influence of aperture effects. To enhance the understanding of correlation between macroscopically detectable acoustic emission signals and microscopic failure mechanisms we simulate the response to different source excitation times, crack surface displacements and displacement directions. The results obtained show good agreement with fundamental assumptions about the crack process reported by various other authors. The simulated acoustic emission signals obtained are compared to experimentally measured waveforms during four-point bending experiments of carbon fiber reinforced plastic structures. The simulated signals of fiber-breakage, matrix-cracking and fiber-matrix interface failure show systematic agreement with the respective experimental signals.