Journal of Sound and Vibration最新文献_第8页

Analysis and mitigation of uncertainties in damage identification by modal-curvature based methods 用基于模态曲率的方法分析和缓解损伤识别中的不确定性

IF 4.3 2区工程技术 Q1 ACOUSTICS

Journal of Sound and Vibration

Pub Date : 2024-10-10 DOI: 10.1016/j.jsv.2024.118769

Daniele Dessi , Fabio Passacantilli , Andrea Venturi

The objective of this paper is to address and reduce the uncertainties associated with measurement noise and discretization in damage identification methods based on modal curvature analysis. The experimental case study considers the local reduction in the bending stiffness of a slender beam under free-free and simply supported boundary conditions. First, the analysis of error sources and their propagation is theoretically set up. Second, the mitigation of uncertainties in damage localization is pursued using a two-stage approach based on multiple hypothesis testing relative to the normalized indices and the definition of a combined macro-index. Finally, the Monte Carlo method is exploited to obtain the statistical error distribution of the experimental damage position and severity predictions by randomizing the numerical displacement mode shapes with the identified noise. The present analysis allows us to find the optimal number of sensors that minimizes the combination of bias and truncation errors, to highlight how sensor spacing and data noise affect damage localization, and to determine the uncertainty bounds of the predicted damage severity. The two-stage approach, enhanced by selecting thresholds related to real noise levels and tuned on SHM objectives, appears to improve identification accuracy compared to the separate use of damage indices based on absolute confidence levels.

本文旨在解决和减少基于模态曲率分析的损伤识别方法中与测量噪声和离散化相关的不确定性。实验案例研究考虑了在自由和简支撑边界条件下细长梁弯曲刚度的局部减小。首先，从理论上分析了误差源及其传播。其次，使用基于归一化指数的多重假设检验和综合宏观指数定义的两阶段方法来减少损伤定位中的不确定性。最后，利用蒙特卡洛方法，通过将数值位移模态振型与已识别的噪声随机化，获得实验损伤位置和严重程度预测的统计误差分布。通过本分析，我们可以找到使偏差和截断误差组合最小化的最佳传感器数量，突出传感器间距和数据噪声对损伤定位的影响，并确定预测损伤严重程度的不确定性边界。与单独使用基于绝对置信度的损坏指数相比，通过选择与实际噪声水平相关的阈值并根据 SHM 目标进行调整的两阶段方法似乎提高了识别精度。

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引用次数: 0

Shape considerations for the design of propellers with trailing edge serrations 带后缘锯齿螺旋桨设计的形状考虑因素

IF 4.3 2区工程技术 Q1 ACOUSTICS

Journal of Sound and Vibration

Pub Date : 2024-10-10 DOI: 10.1016/j.jsv.2024.118771

Jorge Santamaria , André Bierrenbach-Lima , Marlène Sanjosé , Stéphane Moreau

Noise reductions due to trailing edge serrations of several representative unmanned air vehicle propellers are calculated using a low-order methodology based on RANS simulations coupled with an extension of Ayton’s model proposed by Li and Lee, which provides a heuristic three-dimensional model for finite span applicable to rotor blades. The latter model is validated in the limit of zero serration amplitude against Amiet’s and Schlinker and Amiet’s models, finding good agreement at high frequencies for both airfoils and rotating blade elements. Similar good validation results are obtained for finite serrations by comparing with experiments achieved on the Controlled Diffusion airfoil at Université de Sherbrooke, and with calculations for a serrated blade element by Tian and Lyu. The coupled methodology is then validated both aerodynamically and acoustically with ISAE measurements for a representative drone propeller at different rotational speeds. The corresponding serrated model is then used to calculate noise reductions caused by different shapes. The square wave serration is shown to outperform the sawtooth and sinusoidal shapes for all frequencies and observer angles for small propeller blades typically used for drones. Yet, for larger chord blades typically used for ducted fans, combinations of sawtooth and sinusoidal serrations provide better noise reductions.

采用基于 RANS 模拟的低阶方法，结合 Li 和 Lee 提出的 Ayton 模型扩展，计算了几种具有代表性的无人驾驶航空飞行器螺旋桨后缘锯齿造成的噪声降低。在锯齿振幅为零的极限条件下，后一模型与 Amiet 模型以及 Schlinker 和 Amiet 模型进行了验证，发现在高频率下，机翼和旋转叶片元素之间的一致性很好。通过与舍布鲁克大学在受控扩散机翼上进行的实验以及 Tian 和 Lyu 对锯齿叶片元件的计算进行比较，对有限锯齿也获得了类似的良好验证结果。然后，通过对具有代表性的无人机螺旋桨在不同转速下的 ISAE 测量结果，对耦合方法进行了空气动力学和声学验证。然后，使用相应的锯齿模型计算不同形状造成的噪声降低。对于通常用于无人机的小型螺旋桨叶片，在所有频率和观察角下，方波锯齿形都优于锯齿形和正弦形。然而，对于通常用于管道风扇的较大弦叶片，锯齿和正弦锯齿的组合具有更好的降噪效果。

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引用次数: 0

Enhancing wave retarding and sound absorption performances in perforation-modulated sonic black hole structures 增强穿孔调制声波黑洞结构的阻波和吸声性能

IF 4.3 2区工程技术 Q1 ACOUSTICS

Journal of Sound and Vibration

Pub Date : 2024-10-09 DOI: 10.1016/j.jsv.2024.118765

Sihui Li, Xiang Yu, Li Cheng

Sonic black hole (SBH) effects in a retarding duct can be exploited for sound wave manipulation and absorption. The phenomenon relies on two fundamental physical mechanisms: wave speed reduction and energy dissipation. In this study, we demonstrate that these two physical processes can be meticulously balanced through adjusting the perforation parameters in a perforation-modulated SBH (PMSBH). To elucidate the mechanism of slow wave generation and the effect of perforation parameters, an analytic model based on the Wentzel-Kramers-Brillouin (WKB) solutions to the linear acoustic wave equation is established. Alongside transient finite element simulations, the study unveils the roles that major physical parameters play in terms of regulating sound speed and sound absorption. The perforation ratio of the PMSBH is identified as the dominant factor affecting the slow-sound effect, with an optimal range of above 10 % for a PMSBH with densely segmented internal rings. Owing to the inclusion of the perforated boundary, prominent slow wave effects can still be maintained even with a reduced number of rings, provided that the perforation ratio is properly chosen within a reduced variation range. In both cases, the identified perforation ratio largely exceeds the conventional range widely adopted in the micro-perforation community when the slow wave effects are absent. On top of this, tuning the hole size can further enhance air friction for better sound absorption. Theoretical and numerical findings are experimentally validated, and the performance of the PMSBH is demonstrated. While bringing forward the concept of tunable design, this study offers physical insights and guidance for realizing effective sound absorbers embracing slow wave principles and perforation-induced sound absorption.

阻滞管道中的声波黑洞（SBH）效应可用于声波操纵和吸收。这种现象依赖于两种基本物理机制：波速降低和能量耗散。在本研究中，我们证明了这两个物理过程可以通过调整穿孔调制 SBH（PMSBH）中的穿孔参数来实现微妙的平衡。为了阐明慢波产生的机制和穿孔参数的影响，我们建立了一个基于线性声波方程的 Wentzel-Kramers-Brillouin (WKB) 解法的分析模型。通过瞬态有限元模拟，研究揭示了主要物理参数在调节声速和吸声方面的作用。PMSBH 的穿孔率被认为是影响慢声效应的主要因素，对于具有密集分段内环的 PMSBH 而言，最佳穿孔率范围在 10% 以上。由于包含了穿孔边界，即使环数减少，只要在较小的变化范围内适当选择穿孔率，仍能保持突出的慢波效应。在这两种情况下，当没有慢波效应时，所确定的穿孔率大大超出了微穿孔界广泛采用的常规范围。除此以外，调整孔径还能进一步增强空气摩擦力，从而获得更好的吸音效果。实验验证了理论和数值结果，并展示了 PMSBH 的性能。这项研究在提出可调设计概念的同时，还为实现包含慢波原理和穿孔吸声的有效吸声装置提供了物理见解和指导。

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引用次数: 0

Nonlinear free vibrations of a structurally tailored anisotropic pre-twisted thin-walled beam subjected to large deformations 受大变形影响的结构定制各向异性预扭曲薄壁梁的非线性自由振动

IF 4.3 2区工程技术 Q1 ACOUSTICS

Journal of Sound and Vibration

Pub Date : 2024-10-09 DOI: 10.1016/j.jsv.2024.118766

G. Deepak Kumar, B. Panigrahi

It is essential to understand the nonlinear free vibration behaviour of a thin-walled composite structure as they find their applications in harsher environments prone to large deformations. Further, these structures made of fibrous materials, have directional properties for different fibre orientations resulting in a diversified and a complex nonlinear behaviour. In this regard, present work provides a comprehensive mathematical formulation on nonlinear vibration of pre-twisted thin-walled anisotropic box beam. The mathematical model is derived as coupled (flap-lag-extension-torsion) model considering shear deformation and green's strain tensor for large displacements in order to study the influence of nonlinear couplings on the dynamic behaviour. The derived energy equations are presented depending on degree of nonlinearity. These nonlinear equations those derived are nondimensionalized and solved with in the frame work of energy method using classical Ritz approximation. An iterative method is used to solve the nonlinear equations pertaining displacement terms. This nonlinear behaviour is evaluated for two important types of structural tailoring techniques available for thin-walled composite beams namely Circumferentially Asymmetric Stiffness (CAS) and Circumferentially Uniform Stiffness (CUS). It is found that CAS layup experiences significantly severe nonlinear effects compared to CUS due to the presence of 3rd degree nonlinear coupling terms. The variation of nonlinear frequency ratios over different ply angles showing the influence of nonlinearity on fibres orientation is presented for the first time for the two ply lay ups. The influence of degree of nonlinearity on the accuracy of the nonlinear frequencies is evaluated and presented. Moreover, the impact of nonlinearity on the pre-twisted beam is presented for different pre-twist angles.

了解薄壁复合材料结构的非线性自由振动行为至关重要，因为它们应用于容易发生大变形的恶劣环境中。此外，这些由纤维材料制成的结构具有不同纤维取向的定向特性，从而导致了多样化和复杂的非线性行为。为此，本研究针对预扭薄壁各向异性箱梁的非线性振动提供了一个全面的数学模型。考虑到大位移时的剪切变形和格林应变张量，数学模型被推导为耦合（瓣-滞后-拉伸-扭转）模型，以研究非线性耦合对动态行为的影响。推导出的能量方程取决于非线性程度。这些推导出的非线性方程被非尺寸化，并在能量法的框架内使用经典的里兹近似法求解。迭代法用于求解与位移项有关的非线性方程。针对薄壁复合梁的两种重要结构裁剪技术，即环向不对称刚度（CAS）和环向均匀刚度（CUS），对这种非线性行为进行了评估。研究发现，由于存在三度非线性耦合项，与 CUS 相比，CAS 布局会产生严重的非线性效应。对于两种层叠结构，首次提出了非线性频率比在不同层叠角度上的变化，显示了非线性对纤维取向的影响。评估并展示了非线性度对非线性频率精度的影响。此外，还介绍了不同预扭角度下非线性对预扭梁的影响。

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引用次数: 0

Nonlinear normal modes and response to random inputs of systems with bilinear stiffness 具有双线性刚度的系统的非线性法向模式和对随机输入的响应

IF 4.3 2区工程技术 Q1 ACOUSTICS

Journal of Sound and Vibration

Pub Date : 2024-10-09 DOI: 10.1016/j.jsv.2024.118767

Brennen Clark , Matthew S. Allen , Benjamin Pacini

This work seeks to provide a comprehensive review of the effects that stiffness bilinearity can have on the nonlinear modes of a system, its response in a random vibration environment, and the connection between the two. Stiffness bilinearity here refers to a continuous piecewise linear force vs displacement function that is composed of two linear regions. This work focuses on a bilinear stiffness function that is regularized so there is a smooth transition at the point where the two linear regions meet. A single-degree-of-freedom system (SDOF) and a two-degree-of-freedom (2DOF) system are explored and several interesting behaviors are shown. The SDOF bilinear spring model is characterized by four parameters: the low amplitude frequency, the ratio of the linear stiffnesses on either side of the transition, the displacement at which the transition occurs, and the rate or sharpness of the transition. The effect of each parameter on the shape of the NNM is described. In a 2DOF system, these parameters have similar effects, but modal coupling is found to play a significant role. When a bilinear system is subjected to random excitation, many harmonics appear in the response for both the SDOF and 2DOF cases. The root-mean-square (RMS) response of the bilinear system can be larger or smaller than the corresponding linear case depending on the values of the parameters and the type of forcing (broadband, bandlimited, in the shape of a vibration mode, etc.). However, many cases were observed in which the RMS response of the bilinear system was almost the same as that of a linear system, and hence the response could be predicted well using linear analysis. It is hoped that the results presented herein can assist engineers in helping to determine when linear analysis would be adequate to predict the failure of a system, when a rigorous nonlinear analysis is required, and what phenomena are likely to be observed in the latter case.

本研究旨在全面回顾刚度双线性对系统非线性模式的影响、系统在随机振动环境中的响应以及两者之间的联系。这里的刚度双线性是指由两个线性区域组成的连续片断线性力与位移函数。这项工作的重点是对双线性刚度函数进行正则化处理，从而在两个线性区域的交汇点实现平滑过渡。对一个单自由度系统（SDOF）和一个双自由度系统（2DOF）进行了探索，并展示了一些有趣的行为。SDOF 双线性弹簧模型由四个参数表征：低振幅频率、过渡两侧的线性刚度比、发生过渡时的位移以及过渡的速率或尖锐度。本文介绍了每个参数对 NNM 形状的影响。在 2DOF 系统中，这些参数具有相似的效果，但模态耦合起着重要作用。当双线性系统受到随机激励时，SDOF 和 2DOF 的响应中都会出现许多谐波。双线性系统的均方根（RMS）响应可能大于或小于相应的线性情况，这取决于参数值和激励类型（宽带、带限、振型等）。不过，在许多情况下，双线性系统的有效值响应与线性系统几乎相同，因此可以通过线性分析很好地预测响应。希望本文介绍的结果能够帮助工程师确定何时线性分析足以预测系统故障，何时需要进行严格的非线性分析，以及在后一种情况下可能观察到的现象。

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引用次数: 0

Exact closed-form solution for buckling and free vibration of pipes conveying fluid with intermediate elastic supports 带中间弹性支撑的流体输送管道屈曲和自由振动的精确闭式解

IF 4.3 2区工程技术 Q1 ACOUSTICS

Journal of Sound and Vibration

Pub Date : 2024-10-09 DOI: 10.1016/j.jsv.2024.118762

Bo Zhu , Ji Zuo Feng , Yang Guo , Yan Qing Wang

In this paper, the exact closed-form solution is given to investigate the influence of the intermediate elastic support on the buckling and free vibration of an elastically supported pipe. According to the Euler–Bernoulli beam theory, the mechanical model of the pipe is established. The exact equilibrium configuration is derived using the generalised function method without enforcing continuity conditions. A simple solution to the eigenvalue problem is formulated using the methods of complex mode superposition and Laplace transformation. The comparative study shows the differences in the supercritical vibration characteristics and highlights the limitations of previous studies. Parametric studies are carried out to investigate the influence of elastic support and intermediate support conditions on the equilibrium configuration, critical flow velocity, and natural frequency. The results demonstrate that the proposed closed-form solution can determine the support conditions that lead to the maximum critical flow velocity and natural frequency of a pipe with multiple intermediate supports. The maximum values are required to adjust the support conditions leading to the nodes of higher-order equilibrium configurations and complex modes. Furthermore, the natural frequencies of the pipe conveying supercritical fluid no longer satisfy the monotonicity for the support stiffness, the symmetry for the support position, and the ‘zero-point’ property for the support number.

本文给出了精确的闭式解，以研究中间弹性支撑对弹性支撑管道屈曲和自由振动的影响。根据欧拉-伯努利梁理论，建立了管道的力学模型。利用广义函数法推导出精确的平衡构型，无需强制执行连续性条件。利用复模叠加和拉普拉斯变换的方法制定了特征值问题的简单解决方案。对比研究显示了超临界振动特性的差异，并强调了以往研究的局限性。通过参数研究，探讨了弹性支撑和中间支撑条件对平衡构型、临界流速和固有频率的影响。结果表明，所提出的闭式解法可以确定支撑条件，从而使具有多个中间支撑的管道达到最大临界流速和固有频率。最大值是调整支撑条件的必要条件，可导致高阶平衡配置和复杂模态的节点。此外，输送超临界流体管道的固有频率不再满足支撑刚度的单调性、支撑位置的对称性和支撑数量的 "零点 "特性。

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引用次数: 0

Spatial and frequency identification of the dynamic properties of thin plates with the Frequency-Adapted Virtual Fields Method 利用频率适应虚拟场法在空间和频率上识别薄板的动态特性

IF 4.3 2区工程技术 Q1 ACOUSTICS

Journal of Sound and Vibration

Pub Date : 2024-10-09 DOI: 10.1016/j.jsv.2024.118760

Nicolas Madinier , Quentin Leclère , Kerem Ege , Alain Berry

Vibroacoustic inverse methods use the measured response of a vibrating structure to identify a structural parameter or a dynamic load. Two inverse methods are considered, the Force Analysis Technique (FAT) and the Virtual Fields Method (VFM). The Corrected Force Analysis Technique (CFAT) is a variant of FAT that corrects its singularity. This correction allows the method to be applied in the high-frequency domain, when the number of measurement points per flexural wavelength becomes small. In this study, the proposed novelty is the development of a Frequency-Adapted VFM (FA VFM) to the case of a Love–Kirchhoff plate. Thanks to this method, the VFM can now be applied to identify the equivalent bending stiffness and structural damping of a thin plate when the number of measurement points per wavelength is small. The method has previously been developed for an Euler–Bernoulli beam. An experimental identification of the complex bending stiffness of an locally damped aluminium plate using Laser Doppler Velocimetry (LDV) data and the developed method is performed. The experimental study shows for the first time that the FA VFM can be used to map the equivalent bending stiffness and structural damping as a function of position on a plate and identify these parameters as a function of frequency over a large frequency band. The results of the Frequency-Adapted VFM are compared with those of CFAT and the classical VFM approach. FA VFM results are more accurate than those of classical VFM and similar to those of CFAT.

振动声学逆方法利用振动结构的测量响应来确定结构参数或动态载荷。本文考虑了两种反演方法：力分析技术（FAT）和虚拟场法（VFM）。修正力分析技术（CFAT）是 FAT 的一种变体，修正了其奇异性。当每个挠曲波长的测量点数量变少时，该修正方法可应用于高频域。本研究的新颖之处在于针对 Love-Kirchhoff 板开发了频率适应 VFM（FA VFM）。由于采用了这种方法，当每个波长的测量点数量较少时，VFM 现在可用于识别薄板的等效弯曲刚度和结构阻尼。该方法之前已针对欧拉-伯努利梁进行了开发。利用激光多普勒速度仪（LDV）数据和所开发的方法，对局部阻尼铝板的复合弯曲刚度进行了实验鉴定。实验研究首次表明，FA VFM 可用于绘制等效弯曲刚度和结构阻尼与板上位置的函数关系图，并识别这些参数与大频带频率的函数关系。频率调整 VFM 的结果与 CFAT 和经典 VFM 方法的结果进行了比较。频率调整 VFM 的结果比经典 VFM 更精确，与 CFAT 相似。

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引用次数: 0

Indirect measurement of bridge surface roughness using vibration responses of a two-axle moving vehicle based on physics-constrained generative adversarial network 基于物理约束生成式对抗网络，利用双轴行驶车辆的振动响应间接测量桥梁表面粗糙度

IF 4.3 2区工程技术 Q1 ACOUSTICS

Journal of Sound and Vibration

Pub Date : 2024-10-08 DOI: 10.1016/j.jsv.2024.118763

Junyong Zhou , Zhanyu Zhang , Zeren Jin , Xuan Kong , Xiaohui Wang , Hai Liu

This study addresses the challenge of indirectly measuring bridge surface roughness through the vibration responses of a moving vehicle, which is crucial for pavement maintenance and bridge safety assessment. A physics-constrained generative adversarial network (PC-GAN) was proposed for the probabilistic estimation of surface roughness. The method consists of two steps: initially, a GAN informed by physics-based knowledge extracts combined information of bridge vibration deflection and surface roughness from vehicle accelerations. Subsequently, a feed-forward network isolates the bridge surface roughness from the combined data. Numerical examples validate the PC-GAN method, demonstrating sustained high accuracy under challenging conditions, including ISO 8608 level C road roughness, vehicle speeds up to 8 m s^-1, 10 % deviation in vehicle parameters, 10 % environmental noise, and 10 % vehicle damping ratio. Laboratory tests further confirmed the method's efficacy, with the successful detection of artificial barriers on the bridge surface and a mean relative error of 3.33 % in height estimation. The PC-GAN method is demonstrated to be a robust tool for estimating bridge surface roughness under various numerical and laboratory conditions. These findings provide valuable insights for the rapid inspection of bridge pavement conditions using vibration responses from moving test vehicles.

本研究解决了通过移动车辆的振动响应间接测量桥梁表面粗糙度的难题，这对路面维护和桥梁安全评估至关重要。针对表面粗糙度的概率估算，提出了一种物理约束生成式对抗网络（PC-GAN）。该方法包括两个步骤：首先，基于物理知识的生成式对抗网络从车辆加速度中提取桥梁振动挠度和表面粗糙度的综合信息。随后，前馈网络从综合数据中分离出桥梁表面粗糙度。数值示例验证了 PC-GAN 方法，证明该方法在具有挑战性的条件下仍能保持高精度，包括 ISO 8608 C 级路面粗糙度、最高 8 m s-1 的车辆速度、10 % 的车辆参数偏差、10 % 的环境噪声和 10 % 的车辆阻尼比。实验室测试进一步证实了该方法的有效性，成功检测到桥面上的人工障碍物，高度估计的平均相对误差为 3.33%。PC-GAN 方法被证明是在各种数值和实验室条件下估算桥梁表面粗糙度的可靠工具。这些发现为利用移动测试车辆的振动响应快速检测桥梁路面状况提供了宝贵的见解。

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引用次数: 0

Super-resolution localization and orientation estimation of multiple dipole sound sources: From a maximum likelihood framework to wind tunnel validation 多偶极声源的超分辨率定位和方位估计：从最大似然法框架到风洞验证

IF 4.3 2区工程技术 Q1 ACOUSTICS

Journal of Sound and Vibration

Pub Date : 2024-10-05 DOI: 10.1016/j.jsv.2024.118764

Jianing Li, Xun Wang

This paper investigates the identification of multiple dipole sound sources using sound pressures measured from a microphone array. The problem is addressed in the maximum likelihood (ML) framework, where the locations, orientations, and powers of multiple dipole sound sources are unknown parameters to be estimated. By the consistency property of ML, the estimated parameters converge to their actual values, which implies an asymptotically perfect spatial resolution, if a sufficiently high signal-to-noise ratio can be achieved. In order to reduce the dimension of the optimization problem of ML, the contribution of each dipole source to the measured pressures is assumed to be a latent variable and the ML problem is equivalently solved via the expectation–maximization (EM) algorithm, which iteratively and sequentially updates each source contribution and the associated sound source parameters. The number of sound sources can also be determined by the model selection approaches which add a penalty of model dimension to the ML objective function. The proposed method is assessed via a laboratory experiment where the sound field is produced by dipole speakers and a wind tunnel experiment where airframe aerodynamic noise is generated at a high Reynolds number. Experimental results show that the proposed method outperforms existing approaches in the sense of higher spatial resolution, more accurate localization, and the capacity to identify the orientations of multiple dipole sound sources.

本文研究了利用麦克风阵列测得的声压识别多个偶极声源的问题。该问题是在最大似然法（ML）框架下解决的，多个偶极声源的位置、方向和功率都是需要估计的未知参数。根据最大似然法的一致性特性，如果能达到足够高的信噪比，估计参数会收敛到其实际值，这意味着空间分辨率近似完美。为了降低 ML 优化问题的维度，每个偶极声源对测量压力的贡献被假定为一个潜变量，ML 问题可等效地通过期望最大化（EM）算法来解决，该算法会迭代并依次更新每个声源贡献和相关声源参数。声源的数量也可以通过模型选择方法来确定，这种方法在 ML 目标函数中增加了模型维度的惩罚。通过偶极子扬声器产生声场的实验室实验和在高雷诺数下产生机身空气动力噪声的风洞实验，对所提出的方法进行了评估。实验结果表明，所提出的方法在更高的空间分辨率、更精确的定位以及识别多个偶极声源方向的能力方面优于现有方法。

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引用次数: 0

The design of two-dimensional elastic diffusers 二维弹性扩散器的设计

IF 4.3 2区工程技术 Q1 ACOUSTICS

Journal of Sound and Vibration

Pub Date : 2024-10-03 DOI: 10.1016/j.jsv.2024.118759

F.J.P. Allison , S.G. Haslinger , Ö. Selsil , F. Shi

The ability to design surfaces with specific scattering properties has widespread applicability. In this article, we leverage a stochastic method for designing randomly rough, two-dimensional surfaces with a prescribed mean angular intensity distribution. Analytical and numerical techniques are implemented for a linearly elastic medium-vacuum interface, to generate band-limited diffusers with square and elliptical domains of scattering. Longitudinal incidence is assumed, and the theory allows for bulk wave mode conversions. Multivalued, discontinuous surfaces are formulated, and it is shown that the theoretical model may be satisfied independently of the facet shape utilised, with square and hexagonal discretisations given as examples. In the context of elastic wave scattering, the surfaces presented in this article may have applications in the calibration of scatterometers for wave manipulation as well as for crack detection using ultrasound.

设计具有特定散射特性的表面的能力具有广泛的适用性。在本文中，我们利用随机方法设计具有规定平均角强度分布的随机粗糙二维表面。我们针对线性弹性介质-真空界面采用了分析和数值技术，以生成具有方形和椭圆形散射域的带限扩散器。假设为纵向入射，理论允许体波模式转换。多值、不连续表面被提出来，并证明理论模型可以满足所使用的面形状的要求，并给出了方形和六角形离散的例子。在弹性波散射方面，本文提出的曲面可应用于波浪操纵散射计的校准以及使用超声波进行裂缝检测。

引用次数: 0