Designing SHM system using laser vibrometer-based sensor synthesis

25.09.2025 Designing SHM system using laser vibrometer-based sensor synthesis Jakub Spytek1, Siddhesh Raorane1, Lukasz Ambroziński1, Paweł Paćko1, Tadeusz Stepiński1 1AGH University of Kraków, A. Mickiewicza 30, 30-059 Kraków, Poland 1 About GENEX HPC - UGW Simulation ML detection algorithms Fracture & Fatigue ROM model Validation n Characterization Sensor network optimization Wireless communication Remaining useful life prediction 2 Problem description •Sensor placement strategy that yields maximum damage detectability in the selected Region of Interest (ROI). •Guided waves to be used for monitoring of planar and L-bent structures. •Macro-fiber composites (MFC) sensors used (Smart Material Corp) due to their flexibility and ease of integration with the structure. •Strategy involves placement of sensors around the ROI. 3 Characterization of the sample 4 •CFRP specimen representing real structure investigated experimentally. •Specimens: baseline and sample with two artificial defects. •Determine anisotropy, attenuation, and sensitivity of Lamb modes to defects. •Lamb waves excited using PZT disc, responses measured using PSV-500 SLDV. •Excitation using frequency sweep between 40 and 500 kHz, 1 ms duration. •Signal-to-noise ratio (SNR) increased using pulse-compression. Dispersion curves 5 •Dispersion curves calculated using 3D Fourier Transform of the full-field measurement. •Modes A0 and S0 visible in the f-K spectrum. •Mode A0 with slight anisotropy, mode S0 with significant anisotropy. •Usable frequencies up to 220 –250 kHz. Higher frequencies limited due to attenuation. Defect properties - scattering 6 •wavefield snapshots •incident wave filtered (reflections only) Telfon inserts Defect properties – local wavenumber 7 •To determine the influence of defects on Lamb waves, local wavenumber estimation (LWE) is used. •LWE assumes filtering the space-time wavefield to retain a single Lamb mode at a selected frequency. •The resulting 2D map shows distribution of local wavenumber. •Higher wavenumber values visible at the location of defect. •Background wavenumber values irregular –result from inhomogeneity of the plate. LWE Sensor network selection 8 •Properties of the plate and the defect lead to the use of pitch-catch sensor configuration. •Due to inhomogeneity and anisotropy of the plate, sensor placement was determined using experimental analysis. •To reduce the material usage, the analysis can be streamlined using virtualisation. •Artificial defect and virtual sensor can be used to determine the best placement of physical transducers in the pitch-catch configuration. •Virtual sensor involves representing the properties of the physical transducer using measurements with Scanning Laser-Doppler Vibrometer. •Artifical defect involves substituting the real defect with added material that represents properties of a real defect. physical setup virtual setup Artificial defect 9 •Typically, defects can be introduced into the sample during layup or by impact. •To preserve the sample, the distortions to the wavefield can be obtained by adding material. •In this work, a paste with abrasives is added on top of the sample. •The LWE of the area with the paste compares well with the wavenumber of a damaged region. •delamination •paste radius = 25 mm height = 3 mm 25.09.2025 Designing SHM system using laser vibrometer-based sensor synthesis Jakub Spytek1, Siddhesh Raorane1, Lukasz Ambroziński1, Paweł Paćko1, Tadeusz Stepiński1 1AGH University of Kraków, A. Mickiewicza 30, 30-059 Kraków, Poland 16 Thank you for your attention! Characterization of the MFCs 17 MFC M0714P2 160-200 kHz120-160 kHz80-120 kHz MFC M2807P2 160-200 kHz120-160 kHz80-120 kHz Attenuation 18 •Attenuation estimated for line scans at orientations 0, 45 and 90 degrees. •Mode A0 isolated using frequency – wavenumber filter. •Curve-fitting to the exponential decay formula for different frequencies. •Attenuation curve smoothed with moving average filter (n = 7). Fullfield imaging 19