Multiphysics Simulation of Low-Amplitude Acoustic Wave Detection by Piezoelectric Wafer Active Sensors Validated by In-Situ AE-Fatigue Experiment

Abstract

Piezoelectric wafer active sensors (PWAS) are commonly used for detecting Lamb waves for structural health monitoring application. However, in most applications of active sensing, the signals are of high-amplitude and easy to detect. In this article, we have shown a new avenue of using the PWAS transducer for detecting the low-amplitude fatigue-crack related acoustic emission (AE) signals. Multiphysics finite element (FE) simulations were performed with two PWAS transducers bonded to the structure. Various configurations of the sensors were studied by using the simulations. One PWAS was placed near to the fatigue-crack and the other one was placed at a certain distance from the crack. The simulated AE event was generated at the crack tip. The simulation results showed that both PWAS transducers were capable of sensing the AE signals. To validate the multiphysics simulation results, an in-situ AE-fatigue experiment was performed. Two PWAS transducers were bonded to the thin aerospace test coupon. The fatigue crack was generated in the test coupon which had produced low-amplitude acoustic waves. The low-amplitude fatigue-crack related AE signals were successfully captured by the PWAS transducers. The distance effect on the captured AE signals was also studied. It has been shown that some high-frequency contents of the AE signal have developed as they travel away from the crack.

Validation of Self‐Healing Properties of Construction Materials through Nondestructive and Minimal Invasive Testing

“…When increasing the dimensions of the test specimens and introducing multiple crack formations from four‐point bending tests, acoustic emission signals can increasingly be drowned in noise or characteristics of the often‐used acoustic emission parameters (energy, frequency) are even more changed than for, e.g., lab‐scale beams . Thus, if the distance between the acoustic source and the sensor placement increases, the signal becomes significantly weaker due to geometric spreading . Additionally, localization becomes progressively more complex due to the increasing migration of microcracks.…”

Least-squares reverse time migration (LSRTM) for damage imaging using Lamb waves

“…Different transducer types are suitable for various ultrasonic guided wave applications. Excitation or reception components can be piezoelectric wafers [7,8], shear-horizontal transducers [9,10], polyvinylidene difluoride (PVDF) transducers [11], air-coupled transducers [12,13], pulsedlaser [14] and laser Doppler vibrometer (LDV) [15]. The patterns for transducer distribution vary from sparse array [16] to densely distributed arrays [17,18], and full-aperture array [19,20].…”

Guided wave tomography based on least-squares reverse-time migration

“…3 Signals measured by various types of ultrasonic sensors can be converted to diagnostic results. [4][5][6][7][8][9] One category of ultrasonic damage diagnostic methods directly creates the results as damage indices or images. A damage index can be defined in various manners 10,11 for monitoring a path between a pair of sensors.…”

“…3 Signals measured by various types of ultrasonic sensors can be converted to diagnostic results. 4–9…”