Acoustic 'black holes' for flexural waves as effective vibration dampers
Acoustic 'black holes' for flexural waves as effective vibration dampers
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DOI：
10.1016/j.jsv.2003.05.010
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发表时间：
2004-07-22
影响因子：
4.7
通讯作者：
Tilman, FJBS
中科院分区：
文献类型：
--
作者：
Krylov, VV;Tilman, FJBS
厚度逐渐减小到零的弹性板（弹性楔）可以支持各种不寻常的影响，弯曲波向尖锐的边缘传播，这样的结构和反射回来。特别有趣的现象可能发生在板边缘的情况下，其横截面由局部厚度h和到边缘的距离x之间的幂律关系描述：h（x）= ε x（m），其中m是正有理数，ε是常数。特别地，对于m大于或等于2英寸的自由楔形物，以及对于m大于或等于5/3英寸的浸没楔形物，入射弯曲波在边缘附近被捕获并且不反射回来，即，上述结构表示弯曲波的声学“黑洞”。然而，由于在真实的制造的楔形物中始终存在边缘截断，因此相应的反射系数总是远离零。本文表明，在平板表面沉积吸收薄层可以显著地降低反射系数。因此，特定楔形几何形状和薄吸收层的组合效果可以导致用于弯曲振动的非常有效的阻尼系统。(C)2003爱思唯尔有限公司。保留所有权利。
Elastic plates of variable thickness gradually decreasing to zero (elastic wedges) can support a variety of unusual effects for flexural waves propagating towards sharp edges of such structures and reflecting back. Especially interesting phenomena may take place in the case of plate edges having cross-sections described by a power law relationship between the local thickness h and the distance from the edge x:h(x) = epsilonx(m), where m is a positive rational number and epsilon is a constant. In particular, for m greater than or equal to 2-in free wedges, and for m greater than or equal to 5/3-in immersed wedges, the incident flexural waves become trapped near the edge and do not reflect back, i.e., the above structures represent acoustic 'black holes' for flexural waves. However, because of the ever-present edge truncations in real manufactured wedges, the corresponding reflection coefficients are always far from zero. The present paper shows that the deposition of absorbing thin layers on the plate surfaces can dramatically reduce the reflection coefficients. Thus, the combined effect of the specific wedge geometry and of thin absorbing layers can result in very efficient damping systems for flexural vibrations. (C) 2003 Elsevier Ltd. All rights reserved.