研究了温度对铝合金薄板中零群速度(ZGV)Lamb波频率的影响。建立了基于多普勒测振仪的全光学探测与脉冲激光激发不同温度的铝合金薄板中S1-ZGV模式的实验系统,得到铝合金薄板中S1-ZGV模式频率随温度的变化。随着温度从20 ℃升高到370 ℃,实验结果表明S1-ZGV模式频率减小了10.4%,理论计算结果表明S1-ZGV模式频率减小了10.9%,实验结果与理论结果比较吻合。进一步从理论上分析了铝合金薄板的厚度、泊松比和横波波速对S1-ZGV模式频率的影响,结果表明:当温度从20 ℃升高到370 ℃时,厚度对S1-ZGV模式频率的影响最小,横波波速对S1-ZGV模式频率的影响最大。

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 S₁-ZGV mode in an aluminum alloy sheet under different temperatures using a pulsed laser based on Doppler vibrometer. The S₁-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 S₁-ZGV mode decreases by 10.4% when the temperature increases from 20 ℃ to 370 ℃, whereas the theoretical results denote that the frequency of the S₁-ZGV mode decreases by 10.9%. Therefore, the experimental results are observed to be consistent with the theoretical results. In addition, when the temperature increases from 20 ℃ to 370 ℃, the effects of the sheet thickness and shear wave velocity on the frequency of the S₁-ZGV mode are 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 S₁-ZGV mode.