PSI - Issue 52

Donato Perfetto et al. / Procedia Structural Integrity 52 (2024) 418–423 Donato Perfetto / Structural Integrity Procedia 00 (2019) 000–000

422

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Figure 3. Normalized signals recorded by PZT 2 for each FE modelling technique.

Table 3. Features extracted from the recorded signals.

−

Modelling technique 3D-Shell approach

Time of flight (µs) Group Velocity (m/s)

Cross Correlation (%)

39.46 31.41 32.41 31.31

5068.18 6368.03 6171.02 6388.43

2D-Shell, offset on the bottom surface 2D-Shell, offset on the middle surface 2D-Shell, offset on the top surface

65.5 82,2 65.5

4. Conclusions In this work, different finite element modelling techniques were analysed to study the guided wave propagation behaviour in a fibre-reinforced composite panel with a geometric discontinuity (i.e., variable thickness region). To excite and sense the diagnostic signal, a couple of piezoelectric transducers was mounted on the panel surface: the actuator was positioned on the thin region, while the receiver on the thick region. A first approach using 3D-Shell formulation (continuum shell elements) for the modelling of the plate was considered as reference, and thus compared with three different computationally cheaper modelling techniques, which involved the use of 2D-Shell (conventional) elements, in order to find the modelling method that better balances the accuracy and the computational costs. Analysing the results in terms of signals features such as time of flight, group velocity and cross correlation, it was found out that the 2D-Shell schematisation characterised by the offset at the middle region provides the best match, allowing to save about 57% of the computational costs compared to the benchmark technique. This work serves as the foundation for the subsequent phases of the research study, which will a large experimental campaign and the study of 3D-Solid FE model, as well as possible 2D-Shell attempts for the modelling of the geometric step, aiming to the comparison of the numerical data against experimental ones. The final goal is to determine and efficient FE procedure capable to reproduce accurately and in a fast way the guided wave propagation behaviour in real engineering structures for the improvement of the UGW-based SHM systems damage detection capability. Acknowledgements This research study was carried out in the framework of the project “GENESIS— self-diaGnostic hydrogEN vESsel Integrity System”, funded by the University of Campania “Luigi Vanvitelli” as part of fundamental and applied research projects programme dedicated to young researchers.