Acoustic emission experiments were performed on polycrystalline and single crystal 99.990/0 aluminium while undergoing tensile deformation. It was found that acoustic emission counts as a function of grain size showed a maximum value at a particular grain size. Furthermore, the slip area associated with this particular grain size corresponded to the threshold level of detectability of single di...

Piezoelectric wafer active sensors (PWAS) are well known for its dual capabilities in structural health monitoring, acting as either actuators or sensors. Due to the variety of deterioration sources and locations of bridge defects, there is currently no single method that can detect and address the potential sources globally. In our research, our use of the PWAS based sensing has the novelty of...

As civil infrastructure ages, the early detection of damage in a structure becomes increasingly important for both life safety and economic reasons. This paper describes the analysis procedures used for beamforming acoustic emission techniques as well as the promising results of preliminary experimental tests on a concrete bridge deck. The method of acoustic emission offers a tool for detecting...

Since the measurement of mechanical sealing film thickness and just-lift-off time is very difficult, the sealing film condition monitoring method based on acoustic emission signal is proposed. The mechanical seal acoustic emission signal present obvious characteristics of time-varying nonlinear and pulsating. In this paper, the acoustic emission signal is used to monitor the seal end faces just...

One of the methods used to investigate the damaged zone in rock structure is the acoustic emission method. This method is based on receiving the elastic waves that are produced by deformation and cracking of the rock mass around the underground excavation. In this research, a study is conducted on the rock samples by a numerical method to investigate the damaged zone caused by the excavat...

− Comparisons of the acoustic emission signals from the pool and microlayer boiling and water drop evaporation are the aim of the paper. The main relationships, dependences and research results will be presented. The mechanism of acoustic emission generation in liquid boiling and evaporation is discussed. Based on a theoretical analysis, a set of random process characteristics in time and frequ...

A preliminary study of Acoustic Emission during orthopaedic screw fixation was performed using polyurethane foam as the bone-simulating material. Three sets of screws, a Dynamic Hip Screw, a small fragment screw and a large fragment screw were investigated, monitoring acoustic emission activity during the screw tightening. Some specimens were overtightened on purpose to investigate the possibil...

This paper did a radial compression fatigue test on glass fiber winding composite tubes, collects acoustic emission signals on different fatigue damages stages, used time frequency analysis techniques of modern wavelet transform, and analyzed the wave form and frequency characteristics of fatigue damaged acoustic emission signals. Three main frequency bands of acoustic emission signal had been ...