Influence of Temperature on Zero-Group-Velocity Lamb Waves of Thin Plate

Herein, the effect of temperature on the frequency of the zero-group-velocity (ZGV) Lamb wave of an aluminum alloy sheet is studied. Further, an experimental system is established for the all -optical detection and excitation of the S-1-ZGV mode in an aluminum alloy sheet under different temperatures using a pulsed laser based on Doppler vibrometer. The S-1-ZGV mode frequency is observed to vary with the temperature in an aluminum alloy sheet. Subsequently, the experimental results denote that the frequency of the S-1-ZGV mode decreases by 10.1% when the temperature increases from 20 degrees C. to 370 degrees C., whereas the theoretical results denote that the frequency of the S-1-ZGV mode decreases by 10.9 %. Therefore, the experimental results arc observed to be consistent with the theoretical results. In addition, when the temperature increases from 20 degrees C. to 370 degrees C, the effects of the sheet thickness and shear wave velocity on the frequency of the S-1-ZGV mode arc observed to be the smallest and largest, respectively, by considering the influences of the sheet thickness, Poisson ratio, and shear wave velocity of the aluminum alloy sheet on the frequency of the S-1-ZGV mode.