An experimental investigation into active structural acoustic cloaking of a flexible cylinder
An experimental investigation into active structural acoustic cloaking of a flexible cylinder
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DOI：
10.1016/j.apacoust.2020.107436
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发表时间：
2020-12-15
影响因子：
3.4
通讯作者：
Daley, Steve
中科院分区：
文献类型：
--
作者：
House, Charlie;Cheer, Jordan;Daley, Steve
在对象的存在对声场具有不良影响的许多应用中，声学地遮盖对象的能力，有效地使对象在声学上不可见是令人感兴趣的。如果可以测量到合适的干扰信号，则可以使用主动控制系统来直接将散射声压降至最低，这充分体现了物体的存在。本文采用一种宽带前馈主动控制系统，通过在弹性散射体上安装一组结构控制源来最小化远场麦克风阵列上的散射声压。利用入射声场作用下的中空圆柱壳的测量数据，对该系统的性能进行了评估，并研究了控制滤波器的因果关系。结果表明，实际的因果性约束限制了有源隐身在较低频率下的性能，但在使用9个控制执行器的阵列中，因果性约束控制器能够在远场散射声功率中实现约10dB的衰减。研究了控制执行器的数量对衰减性能的影响，讨论了系统的实用性，并确定了一些潜在的实现挑战，包括主动结构声隐身系统引起的结构振动水平的增加。(C)2020爱思唯尔有限公司。保留所有权利。
The ability to acoustically cloak an object, effectively making the object acoustically invisible to an outside observer, is of interest in many applications where the presence of an object has an undesirable impact on the sound-field. If a suitable disturbance signal can be measured, an active control system can be used to directly minimise the scattered acoustic pressure, which fully characterises the presence of the body. In this paper, a broadband feedforward active control system is used to minimise the scattered acoustic pressure at a far-field microphone array using an array of structural control sources affixed to the flexible scattering body. The performance of this system is assessed using measured data corresponding to a hollow cylindrical shell subject to an incident acoustic field, and the causality of the control filters is investigated. It is shown that the practical causality constraint limits the performance of the active cloak at lower frequencies, but the causally constrained controller is able to achieve approximately 10 dB of attenuation in the far-field scattered acoustic power, using an array of 9 control actuators. The influence that the number of control actuators has on the attenuation performance is investigated, the practicability of the system is discussed, and a number of potential implementation challenges are identified, including the increased level of structural vibration caused by the active structural acoustic cloaking system. (C) 2020 Elsevier Ltd. All rights reserved.