Detecting damage in rudder stocks under load using electro-mechanical susceptance: Frequency-warping and semi-supervised approaches

Abstract

Active piezoelectric transducers are successfully deployed in recent years for structural health monitoring using guided elastic waves or electro-mechanical impedance (EMI). In both domains, damage detection can be hampered by operational/environmental conditions and low-power constraints. In both domains, processing can be divided into approaches (i) taking into account baselines of the pristine structure as reference, (ii) ingesting an extensive measurement history for clustering to explore anomalies, (iii) incorporating additional information to label a state. The latter approach requires data from complementary sensors, learning from laboratory/field experiments or knowledge from simulations which may be infeasible for complex structures. Semi-supervised approaches are thus gaining popularity: few initial annotations are needed, because labels emerge through clustering and are subsequently used for state classification. In our work, bending and combined bending/torsion studies on rudder stocks are considered regarding EMI-based damage detection in the presence of load. We discuss the underpinnings of our processing. Then, we follow strategy (i) by introducing frequency warping to derive an improved damage indicator (DI). Finally, in a semi-supervised manner, we develop simple rules which even in presence of varying loads need only two frequency points for reliable damage detection. This sparsity-enforcing low-complexity approach is particularly beneficial in energy-aware SHM scenarios.

Health monitoring of steel structures using surface mountable and detachable PZT sensor

“…The EMI technique is also being used in other fields such as shear thickening fluids (Haydarlar et al, 2021a), composite structures (Gu¨emes et al, 2020) and turning process of materials (Sofuog˘lu et al, 2022). There are various damage detection algorithms have been developed based on frequency-warping (Kexel and Moll, 2022), curve fitting (Haydarlar et al, 2021b), cumulative electric power (Soman et al, 2020) and others methods (Tekkalmaz et al, 2021).…”

“…There is no need of complicated data processing or expensive gear as compared to other techniques. Damage location may be easily recognised using an array of such transducers (Kexel and Moll, 2022; Soh et al, 2000). Unlike other local techniques, the EMI technique neither required the use of costly transducers and gear, nor does it require either probe to be moved or the building to be taken out of operation.…”

Potential Benefit of Structural Health Monitoring System on Civil Jet Aircraft

“…In addition to that, starting from diagnosis carried out, it is possible to estimate residual useful life of the monitored object and eventually extend the inspection intervals [ 3 ]. As to the diagnosis phase, several techniques have been focused by the researchers to be applied to aircraft, including ultrasonic guided waves [ 4 , 5 ], guided electromagnetic waves [ 6 ], electromechanical impedance [ 7 ], and vibration response [ 8 ]. Generally, this approach can be either passive (e.g., activated by aircraft boundary layer [ 9 ]) or active [ 10 ] (i.e., enabled by the system).…”

An island-bridge packaging piezoelectric sensor for structural health monitoring in high-strain environments

“…As a type of piezoelectric material with a strong piezoelectric effect, piezoelectric lead-zirconate-titanate (PZT) has been widely applied in various fields due to its advantages of dual sensing and actuation, energy harvesting, high bandwidth, and low cost (Wang et al, 2021; Zhou et al, 2017). Therefore, piezoelectric sensing technologies by utilizing guided wave theory and electromechanical impedance theory (EMI) have attracted great interest at SHM (Fan et al, 2018; Han et al, 2021; Kexel and Moll, 2022; Zhang et al, 2020). However, it is worth noting that until now, the application of piezoelectric sensing for structural monitoring in aerospace and deep-sea equipment has remained a serious challenge.…”