内嵌声学黑洞薄板振动特性数值模拟方法研究

Study on numerical simulation method for vibration characteristics of shell embedded with acoustic black hole

  • 摘要:
      目的  针对内嵌二维声学黑洞薄板的数值模拟方法进行对比研究,
      方法  提出使用板壳单元对声学黑洞薄板进行离散建模的方法。首先,设计内嵌二维声学黑洞薄板算例,应用体单元建立该薄板的有限元模型,以验证其声学黑洞效应。然后,采用相同尺度的板壳单元来模拟该二维声学黑洞薄板,并对2种建模方法的模态和振动特性进行数值对比验证。最后,讨论声学黑洞区域厚度阶梯变化尺度以及幂律对整体结构振动特性的影响。
      结果  研究表明,使用板壳单元离散内嵌声学黑洞薄板计算其振动特性的精度是可靠的,板壳单元离散方法相比体单元离散法具有计算规模小、计算效率高的优点。同时,合理调节声学黑洞区域的厚度阶梯变化尺度以及幂律会改变局部模态对应的固有频率。
      结论  研究结果可为声学黑洞结构的设计与应用提供指导。

     

    Abstract:
      Objectives  To study a numerical simulation method for a plate embedded with a two-dimensional acoustic black hole,
      Methods  a method for discrete modeling of the structure with acoustic black hole by a shell element is proposed. Firstly, an example of a plate embedded with a two-dimensional acoustic black hole is designed in this paper, a finite element model of the plate is established with a solid element, and the acoustic black hole effect of the plate is verified; secondly, the plate embedded with two-dimensional acoustic black hole is simulated with a shell element with the same size, and the modes and vibration responses obtained by the two modeling methods are numerically compared and verified; and finally, the influence of step change scale and power law of acoustic black hole region on the vibration characteristics of the whole structure are discussed.
      Results  The results show that it is reliable to calculate the accuracy of the vibration characteristics of the shell with acoustic black hole by means of shell element dispersion, and the shell element discrete method can reduce the computation scale and improve the computation efficiency compared with the solid element discrete method. At the same time, the reasonable adjustment of the step change scale and power law of the acoustic black hole region will influence the natural frequency of local modes.
      Conclusions  The research results can provide guidance for the design and application of the structure with acoustic black hole.

     

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