The Influence of Sensor Size on Acoustic Emission Waveforms—A Numerical Study

Abstract

Abstract:The performance of Acoustic Emission technique is governed by the measuring efficiency of the piezoelectric sensors usually mounted on the structure surface. In the case of damage of bulk materials or plates, the sensors receive the acoustic waveforms of which the frequency and shape are correlated to the damage mode. This numerical study measures the waveforms received by point, medium and large size sensors and evaluates the effect of sensor size on the acoustic emission signals. Simulations are the only way to quantify the effect of sensor size ensuring that the frequency response of the different sensors is uniform. The cases of horizontal (on the same surface), vertical and diagonal excitation are numerically simulated, and the corresponding elastic wave displacement is measured for different sizes of sensors. It is shown that large size sensors significantly affect the wave magnitude and content in both time and frequency domains and especially in the case of surface wave excitation. The coherence between the original and received waveform is quantified and the numerical findings are experimentally supported. It is concluded that sensors with a size larger than half the size of the excitation wavelength start to seriously influence the accuracy of the AE waveform.

Lamb Modes Detection Using Cumulative Shannon Entropy with Improved Estimation of Arrival Time

“…Moreover, the frequency content of the received waves is also distorted due to the sensor size, increasing the possible distortion due to scattering or reflections. These phenomena are well described in [28].…”

A Review on the Applications of Acoustic Emission Technique in the Study of Stress Corrosion Cracking

“…The table has been structured to highlight for each specific proposed test set up (metallic alloy and environmental conditions applied in the stress corrosion test have been indicated) the analysis approaches used for AE data post-processing. This aspect was, indeed, already raised in literature (e.g., [142]) however, in the analyzed papers, when indicated, wide bandwidth (ranging from 100 kHz up to 1 MHz) AE sensors are generally adopted, thus limiting its discriminating contribute.…”

Acoustic Emission Signal Due to Fiber Break and Fiber Matrix Debonding in Model Composite: A Computational Study

“…AE sensors cannot transmit all the information of the detected signal, not only because of their sensitivities but also because they transmit the information of the average velocity over the surface in contact [56]. Sensor effect was considered with the same procedure described in [51], summarized hereafter.…”