Dual-parameter ultrasonic guided wave packet characterization for ice thickness prediction and excitation signal...

Surface icing on aircraft has long posed a critical threat to flight safety. The risk of stall and loss of control can be markedly elevated due to the degradation of the lift coefficient and the maneuverability of the aircraft, which is caused by the substantial ice accretions. Therefore, the real-time monitoring of ice thickness during flight is essential to enable early warning before safety margins are compromised. In this study, an analytical algorithm for the calculation of Ultrasonic Guided Waves (UGWs) sinusoidal tone burst wave packet evolution is extended to multilayer Transversely Isotropic (TI) waveguides. Its accuracy is confirmed by the comparison of calculation results of transmitted 200 kHz single-cycle Hanning-window-modulated UGW sinusoidal tone burst from the analytical algorithm and the three-dimensional Time Domain Finite Element (TDFE) simulation under various ice dimensions. An experiment is conducted in a cryogenic chamber with PZT-5 wafers for the excitation and sampling of the UGW tone burst in Carbon Fiber Reinforced Plastic (CFRP) laminate under various ice dimensions. The medians and widths of the quarter-peak interval of Mode 2 wave packets are extracted from the experiment results, thus employed together for the dual-parameter wave packet characterization and for the ice thickness prediction under different ice lengths on the basis. The result shows that the average absolute prediction error and the average relative prediction error are 0.10 mm and 18.44% under - 20℃, and 0.12 mm and 21.21% under - 40℃, respectively. Finally, the algorithm is applied to assess the applicability of the excitation signal across varying center frequencies and cycling numbers; an associated optimization criterion is thus proposed.