冰层中Lamb波传播特性的数值模拟和实验研究

Numerical simulation and experimental research of Lamb wave propagation characteristics in ice

  • 摘要: 作为最常用的超声导波之一,Lamb波具有能量集中、传播范围广、沿程衰减小等特点,可以拓展应用于结冰探测领域。为探明Lamb波在冰层中的传播规律,基于Lamb波探冰实验平台构建物理模型,以COMSOL Multiphysics软件为计算工具,数值模拟了不同厚度、不同长度冰层中的Lamb波传播情况。在此基础上,搭建了Lamb波探冰实验平台,开展了无冰铝板和覆冰铝板Lamb波传播实验。结合数值模拟和实验结果,明确了温度、冰层几何特性、液态水对Lamb波传播特性的影响规律。结果表明:温度越低,Lamb波传播群速度越快;在一定冰层厚度范围内,接收端压电片电压幅值衰减量随冰层厚度增大而增大;随着冰层长度增加,接收端Lamb波B1模态时间延迟量线性增大;液态水仅对Lamb波A0模态产生影响,对S0模态影响不大。实验和数值模拟结果具有较好的一致性,为Lamb波结冰探测技术提供了理论参考。

     

    Abstract: As one of the most commonly used ultrasonic guided waves, Lamb wave has the characteristics of concentrated energy, wide propagation range and small probe volume. Its application can be extended to the field of ice detection. In order to explore the propagation law of Lamb wave in ice, this paper constructs a physical model based on the Lamb wave propagation research platform of piezoelectric ceramics, and takes COMSOL Multiphysics software as the calculation tool to simulate the propagation of Lamb wave in ice with different thickness and length. On this basis, the Lamb wave ice detection platform was built, and the Lamb wave propagation experiment of the iced aluminum plate was carried out. Combined with the numerical simulation and experimental results, the effects of temperature, ice geometric characteristics and liquid water on the propagation characteristics of Lamb wave are clarified. The results show that the lower the temperature, the faster the group velocity of Lamb wave propagation; In a certain range of ice thickness, the attenuation of piezoelectric voltage amplitude at the receiver increases with ice thickness; The time delay of Lamb wave B1 mode wave at the receiver increases linearly with the increase of ice length; Liquid water only affects A0 mode of Lamb wave, but has little effect on S0 mode. The experimental and numerical simulation results are in good agreement, which provides a theoretical reference for Lamb wave ice detection technology.

     

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