Journal of Sound and Vibration最新文献

{"title":"Time–frequency-ridges-based synchrosqueezing transform for flexible thin-wall bearing fault diagnosis","authors":"Yanjiang Yu,&nbsp;Xuezhi Zhao","doi":"10.1016/j.jsv.2025.119128","DOIUrl":"10.1016/j.jsv.2025.119128","url":null,"abstract":"<div><div>Within the realm of fault diagnosis, the flexible thin-wall bearing, with its unique kinematic attributes diverging from those of rolling bearings, presents a challenge. The reassignment method, as a post-processing technique in time-frequency analysis, enhances time-frequency representation readability but compromises signal reconstruction. To address this, a time–frequency-ridges-based synchrosqueezing transform is proposed in this paper. Initially, to identify periodic components, the estimation of instantaneous frequency and group delay is obtain as time–frequency ridges from wavelet transform. Then, a localization method is employed to lower the error between the estimation ridges and the true ridges. Furthermore, an energy-intersection method is designed to divide the ridges into impulse and harmonic types. On this basis, the proposed method reassigns the energy of impulsive components and harmonic components separately. Consequently, an improvement in the readability of time-frequency representation is achieved, alongside the preservation of reconstructive ability. Experimental validation using simulated and vibration signals underscores its efficacy in identifying periodic components and providing precise diagnostics for flexible thin-wall bearings.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"611 ","pages":"Article 119128"},"PeriodicalIF":4.3,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143882099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A broadband solid impedance transformer for acoustic transmission between water and air","authors":"Hesam Bakhtiary Yekta,&nbsp;Andrew N. Norris","doi":"10.1016/j.jsv.2025.119120","DOIUrl":"10.1016/j.jsv.2025.119120","url":null,"abstract":"<div><div>Broadband acoustic transmission between air and water can be obtained with a solid interface comprising three parallel thin elastic plates connected by two sets of parallel rigid ribs. Theoretical analysis combined with numerical optimization shows that the optimal 3-plate impedance transformer has a central plate far thicker than those facing air and water. This implies a simpler interpretation of the optimal 3-plate impedance transformer as two elastic plates separated by a mass-like impedance. The properties of the broadband transformer may then be understood using results for a previously studied 2-plate system and asymptotic approximations using the small air-to-water impedance ratio. Optimal systems with water and air-side plates of similar material have relative thicknesses of approximately three to one, respectively, with the central mass having areal density approximately 17 times the water side plate. Further identities relate the frequency of total transmission to the plate thicknesses and to the rib separation length. The impedance transformer is compared to an ideal two layer quarter wavelength model, allowing us to identify a minimal attainable Q-factor of about 5.5, which is achieved in examples presented. The explicit approximations to the optimized parameters also serve as the initial values for numerical optimization, greatly accelerating the process. Together, the theoretical and numerical results point to a remarkably simple class of purely solid impedance transformers, with system parameters well defined by the asymptotically small parameter: the ratio of air-to-water acoustic impedances.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"611 ","pages":"Article 119120"},"PeriodicalIF":4.3,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143899106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fiducial marker-based decentralized computer vision for structural modal identification","authors":"Shivank Mittal,&nbsp;Ayan Sadhu","doi":"10.1016/j.jsv.2025.119152","DOIUrl":"10.1016/j.jsv.2025.119152","url":null,"abstract":"<div><div>Due to the advancement in optics and computer vision, the implementation of the vision-based technique is extensively being investigated for structural health monitoring. Compared with traditional contact sensing measurements, computer-vision technology offers contactless and remote measurements with high spatial density at low cost and instrumentation time. This study proposes an innovative contactless vision-based decentralized vibration measurement technique, where the fiducial marker is utilized as an inexpensive virtual sensor to extract structural vibration measurements using 3D pose estimation through camera calibration. Once the vibration measurements are extracted, covariance-driven stochastic subspace identification is employed due to its robustness for effective mode decomposition and noise reduction capabilities. This paper enables the extraction of 3D time series without deploying a stereo camera system and combines the multiple fields of view of different regions of interest from various cameras in a decentralized manner to capture high-density and high-resolution spatial data for full-field measurement. Two laboratory tests were conducted on a lab-scale building model and a lab-scale beam model to validate the robustness and effectiveness of the proposed methodology. Following the laboratory validation, field tests on a full-scale truss bridge were performed to demonstrate the efficacy of the proposed technique. The relative error in the estimation of the modal frequencies in lab-scale experimentation is &lt;2 %, whereas, for the field study, it is &lt;5.5 %, considering the working distance between the camera and field bridge is over 30 m. The modal assurance criterion (MAC) between the extracted mode shapes is also estimated, and the average MAC values for lab-scale building and lab-scale beam models are 98.61 % and 97.28 %, respectively. The proposed technique has proven to capture the minuscule vibration of the structure at a considerable distance between the structure and the vision-based system, including a detailed comparative study between the vision-based system and accelerometers.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"612 ","pages":"Article 119152"},"PeriodicalIF":4.3,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143894694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Frequency shift due to azimuthal temperature gradients in an annular combustor","authors":"Vishal Acharya,&nbsp;Timothy Lieuwen","doi":"10.1016/j.jsv.2025.119119","DOIUrl":"10.1016/j.jsv.2025.119119","url":null,"abstract":"<div><div>Annular combustors have multiple thermoacoustic modes that are linearly stable or unstable at a wide range of frequencies. Due to azimuthal symmetry, there exist pairs of either degenerate (i.e., two modes with identical frequencies) or weakly degenerate modes (i.e., modes with nearly identical frequency) in the system. This weak but typically nonzero frequency spacing has significant influences on the system’s nonlinear dynamics, such as stability and existence of potential limit cycle solutions. This paper presents a leading order expression for the frequency split and frequency shift in an annular combustor with mean temperature gradients. The analysis is constructed for small values of the relative temperature gradient, <span><math><mi>ϵ</mi></math></span>. For classical 1-D linear acoustics problems, the frequency shift occurs at <span><math><mrow><mi>O</mi><mrow><mo>(</mo><mi>ϵ</mi><mo>)</mo></mrow></mrow></math></span> through integration of the temperature fluctuations in the combustor. However, azimuthal periodicity results in a 0 contribution from this approximation and a detailed linear analysis shows that the linear correction only splits the frequency resulting in a loss of degeneracy. The analysis was extended to second order, as the leading order frequency shift occurs at <span><math><mrow><mi>O</mi><mrow><mo>(</mo><msup><mrow><mi>ϵ</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>)</mo></mrow></mrow></math></span>. Explicit analytical expressions are presented for this second order correction, as well as example calculations quantifying the effect of different combustor parameters on the shift. These results can then be used by those exploring linear and nonlinear dynamics of annular combustion systems.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"611 ","pages":"Article 119119"},"PeriodicalIF":4.3,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143887625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vibration analysis of polygonal plates using triangular energy element via global-local level mapping","authors":"Zhao Jing,&nbsp;Siqi Wang","doi":"10.1016/j.jsv.2025.119138","DOIUrl":"10.1016/j.jsv.2025.119138","url":null,"abstract":"<div><div>A novel numerical integration strategy, based on global-local level mapping, is proposed in the Ritz method, for the vibration analysis of polygonal plates. At the global level, the polygonal plate is embedded in a rectangular domain, and then the rectangular domain is mapped to a unit square domain. The polygonal plate is then divided into multiple triangular domains. At the local level, each triangular domain is mapped to a right-angled triangular domain and then to a unit square domain, from which triangular energy elements are constructed using Gauss-Legendre quadrature via inverse mapping. By applying the global-local level mapping integration strategy to the vibration analysis of polygonal plates, the energy functionals in terms of global admissible functions can be established on the rectangular domain, and the integration of elements in the stiffness and mass matrices can be performed based on triangular energy elements. As a result, the energy functionals and computation procedures for arbitrarily shaped polygonal plates are standard, and will not be affected by variations in the polygonal plate's geometry. The vibrational behaviors of triangular, skew, trapezoidal, pentagonal, hexagonal, heptagonal, and octagonal plates are investigated, and compared with those reported in the literature. Results demonstrate the generalization, reliability, accuracy of the proposed method. This method is universal for solving 2D variational problems on complex geometric domain within Ritz formulation.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"612 ","pages":"Article 119138"},"PeriodicalIF":4.3,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143899660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A parametrized virtual point reduced estimation framework for determining an unknown force’s magnitude, direction and position of action","authors":"Julian Staiger ,&nbsp;Rafael S.O. Dias ,&nbsp;Simon Vanpaemel ,&nbsp;Frank Naets","doi":"10.1016/j.jsv.2025.119113","DOIUrl":"10.1016/j.jsv.2025.119113","url":null,"abstract":"<div><div>This article challenges the question of whether a force applied to a rigid interface can be estimated jointly with its position and direction of action utilizing a model which does not take such a force explicitly into account. Firstly, we discuss linear model-based estimation as a possibility to determine the amplitude, direction and position of a given unknown force acting on a rigid interface. For this purpose, the estimation results of two linear augmented Kalman filters are considered. One configuration delivers estimates for a set of equivalent forces applied to a rigid interface, which are subsequently reduced to a virtual point. The other configuration considers inputs reduced into the virtual point of interest, estimating directly the forces and moments acting on it. After the estimation process, a nonlinear system of equations is solved to characterize an arbitrary unknown acting force in amplitude, position, and direction. Thereafter, this article proposes two novel approaches based on a nonlinear augmented state–space model defined by using the Virtual Point Transformation (VPT) method that incorporates the explicit position or the lever arms of the unknown applied force as well as its direction of action with respect to the considered virtual point as parameters to be estimated. An observability analysis for these nonlinear systems is provided utilizing recent results to determine the observability of nonlinear systems with direct feedthrough and based on Lie derivatives. It was found that only the latter formulation is fully observable and hence an Augmented Extended Kalman Filter (AEKF) parametrized via the lever arms between the unknown force and the considered virtual point is chosen. The proposed methodology is then experimentally validated on an automotive-grade rubber mount component. The results show a superior performance of the nonlinear estimation framework in the time- and frequency-domain over the linear counterparts. Moreover, the unknown position and direction at which the force is applied can be estimated with higher precision and without further processing using the AEKF framework.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"612 ","pages":"Article 119113"},"PeriodicalIF":4.3,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143864314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Self-similar eigenvalue distribution of a binary tree-structured mass–spring–damper system","authors":"Róbert Rochlitz,&nbsp;Bendegúz Dezső Bak,&nbsp;Tamás Kalmár-Nagy","doi":"10.1016/j.jsv.2025.119111","DOIUrl":"10.1016/j.jsv.2025.119111","url":null,"abstract":"<div><div>The eigenvalue distribution of a binary tree-structured multi-degree-of-freedom linear oscillator is examined. The block masses and spring stiffnesses in the model are a power-law function of the tree level. A recursive formula is proven for the characteristic polynomial of the undamped system. For the power-law quotient <span><math><mrow><mi>σ</mi><mo>=</mo><mn>1</mn><mo>/</mo><mn>2</mn></mrow></math></span> the resulting characteristic equation is solved analytically and the eigenvalue distribution is derived as the function of the tree level up to the limit of the infinite tree. The importance of the eigenvalue distribution is demonstrated with examples of the dynamical behavior, when the system is subjected to small mistuning of its block masses. The mistuning perturbs the block masses by drawing a random value from a uniform distribution centered around the base value of each block mass. The width of the uniform distribution for each block mass is given by the product of the base value of the mass and the mistuning parameter <span><math><mi>r</mi></math></span>. The displacement solutions of the governing differential equation with two sets of initial conditions are compared for different values of the mistuning parameter <span><math><mi>r</mi></math></span>. Even though the mistuning has only a small effect on the eigenfrequencies of the system, it is concluded that the small perturbation of the block masses can cause a significant shift in the apparent frequency of the vibration.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"611 ","pages":"Article 119111"},"PeriodicalIF":4.3,"publicationDate":"2025-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143874837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of misaligned flow on trailing-edge noise","authors":"Donghun Kang,&nbsp;Seongkyu Lee","doi":"10.1016/j.jsv.2025.119102","DOIUrl":"10.1016/j.jsv.2025.119102","url":null,"abstract":"<div><div>This study presents the influence of misaligned flow on trailing-edge noise through high-fidelity large-eddy simulations, focusing on a NACA 0012 airfoil at a Reynolds number of <span><math><mrow><mn>4</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>5</mn></mrow></msup></mrow></math></span>, a Mach number of 0.058, and a zero incidence angle. To model misaligned flow, the <span><math><mrow><mn>30</mn><mo>°</mo></mrow></math></span> and <span><math><mrow><mn>45</mn><mo>°</mo></mrow></math></span> swept airfoils are considered. Additionally, we simulate a straight airfoil with reduced Mach numbers equal to the chordwise velocity component of the swept airfoil, without spanwise flows. Numerical results are cross-examined with extended Amiet’s trailing-edge theory for a swept airfoil. It is found that the noise reduction trend with misaligned flow does not exactly correspond to the trend of reduced chordwise velocity. Our findings reveal that the presence of misaligned flow reduces the hydrodynamic wall-pressure spectrum near the trailing edge and generates destructive interference, efficiently mitigating airfoil noise; the latter has a more significant effect than the former. In particular, spanwise anti-phase coherent flow convection is found to be crucial for phase interference, which is not considered in the analytical approach. It is also found that the spanwise correlation length differs between numerical simulations and the generalized Corcos’ model, affecting the discrepancy in the level of noise reduction between numerical results and analytical results. As the acoustic behavior driven by flow misalignment in the swept airfoil represents a simplified flow pattern applicable to serrated geometries and straight blades undergoing the Coriolis effect in rotating motion, this work is anticipated to be instrumental in providing physical insights into practical applications.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"611 ","pages":"Article 119102"},"PeriodicalIF":4.3,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143877306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reconfigurable acoustic focusing based on origami-inspired metalens","authors":"Chen Liu ,&nbsp;Nengyin Wang ,&nbsp;Tuo Liu ,&nbsp;Zhongming Gu ,&nbsp;Yong Li ,&nbsp;Jie Zhu","doi":"10.1016/j.jsv.2025.119096","DOIUrl":"10.1016/j.jsv.2025.119096","url":null,"abstract":"<div><div>In the realm of acoustics, the ability to focus sound using metalenses holds significant promise for various applications. However, contemporary research on such focusing lenses predominantly relies on static structures, lacking adaptability and reconfigurability. In this study, we introduce an innovative, origami-inspired reconfigurable gradient metalens. The novel design comprises foldable V-shaped unit cells, each boasting high transmission efficiency and spanning a full <span><math><mrow><mn>2</mn><mi>π</mi></mrow></math></span> phase shift within the target frequency range. Notably, by merely adjusting the folding angle, we can achieve phase differences of <span><math><mi>π</mi></math></span> between two unit cells at different frequencies, facilitating a versatile and selectable focusing effect characterized by a variable focal length. To further the concept, we demonstrate a metalens using eight distinct foldable unit cells, aiming to achieve pinpoint acoustic focusing through varying folding configurations. To validate this approach, we present evidence from both numerical simulations and experimental measurements of our origami-based reconfigurable metalens. The methodology offers a new perspective in constructing adaptable gradient metalenses and potential applications in acoustic sensors, energy collection devices and imaging systems.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"612 ","pages":"Article 119096"},"PeriodicalIF":4.3,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143870616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Observation of exceptional points in a spherical open elastic system","authors":"Hiroaki Deguchi ,&nbsp;Kei Matsushima ,&nbsp;Takayuki Yamada","doi":"10.1016/j.jsv.2025.119114","DOIUrl":"10.1016/j.jsv.2025.119114","url":null,"abstract":"<div><div>Exceptional points (EPs) are spectral singularities in non-Hermitian systems where eigenvalues and their corresponding eigenstates coalesce simultaneously. In this study, we calculate scattering poles in an open spherical solid and propose a depth-first search-based method to identify EPs. Using the proposed method, we numerically identify multiple EPs in a parameter space and confirm the simultaneous degeneracy of scattering poles through numerical experiments. The proposed method and findings enable the exploration of applications in practical three-dimensional models.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"611 ","pages":"Article 119114"},"PeriodicalIF":4.3,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}