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首页> 外文期刊>Mechanical systems and signal processing >Investigations on flexural wave propagation and attenuation in a modified one-dimensional acoustic black hole using a laser excitation technique
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Investigations on flexural wave propagation and attenuation in a modified one-dimensional acoustic black hole using a laser excitation technique

机译：利用激光激发技术研究改进的一维声黑洞中弯曲波的传播和衰减

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摘要

Acoustic Black Holes (ABHs), as a new type of passive structure for vibration damping enhancement and noise attenuation, have been drawing increasing attentions of many researchers. Due to the difficulty in manufacturing the sharp edges required by the ABH structures, it is important to understand the wave propagation and attenuation process in the presence of damping layers in non-ideal ABHs with a truncated edge. In this paper, an analytical expression of the wave reflection coefficient in a modified one-dimensional ABH is derived and a time-domain experimental method based on a laser excitation technique is used to visualize the wave propagation. In the experimental studies, the flexural waves in the ABH were excited by a scanning pulse laser and measured by a Laser Doppler Vibrometer (LDV). The incident wave and reflected wave were separated from the measured original wave field and the decrease of the wave velocity in the ABH was exhibited. The reflection coefficient was calculated from the ratio of the amplitude of the reflected wave to that of the incident wave for different ABH parameters and different thicknesses of the damping layer. The measured reflection coefficients were used to identify the unknown coefficients in the theoretical formula. The results confirm that there exists an optimal thickness for the damping layer, which leads to the minimum wave reflection. Based on the laser-induced visualization technique and various signal processing and feature extraction methods, the entire process of the wave propagation in a non-ideal one-dimensional ABH structure can be visualized and scrutinized.
机译：声学黑洞（ABHs）作为一种新型的被动结构，可增强减震和降噪效果，已引起许多研究者的关注。由于难以制造ABH结构所需的尖锐边缘，因此了解具有非理想ABH且边缘截短的阻尼层存在时的波传播和衰减过程非常重要。本文推导了改进的一维ABH中波反射系数的解析表达式，并采用基于激光激发技术的时域实验方法可视化了波的传播。在实验研究中，ABH中的弯曲波由扫描脉冲激光激发并由激光多普勒振动计（LDV）测量。入射波和反射波与测得的原始波场分开，ABH中的波速降低。对于不同的ABH参数和不同的阻尼层厚度，根据反射波与入射波的振幅之比计算反射系数。测量的反射系数用于确定理论公式中的未知系数。结果证实阻尼层存在最佳厚度，从而使波反射最小。基于激光诱导的可视化技术以及各种信号处理和特征提取方法，可以对非理想的一维ABH结构中的波传播的整个过程进行可视化和检查。

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  • 来源
    《Mechanical systems and signal processing》 |2018年第may1期|19-35|共17页
  • 作者

    Hongli Ji; Jing Luo; Jinhao Qiu; Li Cheng;

  • 作者单位

    State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics & Astronautics, Nanjing, China,Department of Mechanical Engineering, Hong Kong Polytechnic University, Hung Horn, Kowloon, Hong Kong;

    State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics & Astronautics, Nanjing, China;

    State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics & Astronautics, Nanjing, China;

    Department of Mechanical Engineering, Hong Kong Polytechnic University, Hung Horn, Kowloon, Hong Kong;

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  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    Acoustic black holes; Energy trapping; Reflection coefficient; Laser excitation technique; Damping layer;

    机译：声学黑洞;能量陷阱;反射系数;激光激发技术;阻尼层;

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