We describe resonant capacitive MEMS transducers developed for use as acoustic emission detectors, fabricated in the commercial three-layer polysilicon surface micromachining process (MUMPs). The 1-cm square device contains six independent transducers in the frequency range between 100 kHz and 500 kHz, and a seventh transducer at 1 MHz. Each transducer is a parallel plate capacitor with one pla...

This research work highlights the effects of acoustic emission (AE) signals emitted during the milling of H13 tool steel as an important parameter in the identification of tool wear. These generated AE signals provide information on the chip formation, wear, fracture and general deformation. Furthermore, it is aimed at implementing an online monitoring system for machine tools, using a sensor f...

Acoustic Emission monitoring during three-point load test on concrete blocks prepared using variety of glass aggregates indicates that the mode and nature of crack initiation and propagation is highly dependent on the composition and the type of aggregates. The mechanism of crack arresting and bridging can only be investigated using Acoustic Emission. The results obtained are encouraging and le...

This paper aims to present the newly designed acoustic emission AE instrument for the in-situ monitoring of corrosion damages of aircraft structures. The work was theoretically based on the combination of modal AE theory and AE parameter analysis technique. Previous research had shown that identification of corrosion AE and background noise by modal acoustic emission(MAE) technique was possible...

Plastic deformation of crystalline materials is a complex nonhomogeneous process characterized by avalanches in the motion of dislocations. We study the evolution of dislocation loops using an analytically solvable phase-field model of dislocations for ductile single crystals during monotonic loading. The distribution of dislocation loop sizes is given by P(A) approximately A-sigma, with sigma=...

A single bubble of air in water can emit pulses of blue-white light that have durations of less than 50 ps while it is oscillating in an acoustic standing wave. The emission is called sonoluminescence. A knowledge of the bubble diameter throughout the cycle, and in particular near the time of sonoluminescence emission, can provide important information about the phenomenon. A new Mie scattering...

Continuous measurement of size distribution of particles is the necessary parameter regarding the control of some specific production processes. A possible solution is the use of the acoustic emission method which is based on the measurement and analysis of pressure pulses generated by an impact of solid particles against a solid obstacle. Our paper focuses on the practical verification of the ...

The acoustic emission technique is proposed for assessing the irreversible phenomena occurring during hydrogen absorption/desorption cycling in LaNi5. In particular, we have studied, through a parametric analysis of in situ detected signals, the correlation between acoustic emission (AE) parameters and the processes occurring during the activation of an intermetallic compound. Decreases in the ...

Acoustic emission-based techniques are promising for nondestructive inspection of mechanical systems. For reliable automatic fault monitoring, it is important to identify the transient crack-related signals in the presence of strong timevarying noise and other interference. In this paper we propose the application of the Kohonen network for this purpose. The principal components of the short-ti...

The National Bureau of Standards (NBS) is beginning to provide a mechanism for traceability for a number of NDE measurement procedures, an activity that is expected to have a significant, positive impact on the reproducibility and accuracy of NDE measurements. Much of the NDE standards activity has been in ultrasonics and acoustic emission, this effort leading to calibration services for ultras...