Pub Date : 2026-04-28Epub Date: 2026-01-16DOI: 10.1016/j.jsv.2026.119660
Giacomo Abbasciano , Balázs Endrész , Gábor Stépán , George Haller
We illustrate how the recent theory of Spectral Submanifolds (SSM) can capture global bifurcations and complex dynamics in mechanical systems even under delay and spatial discretization. Specifically, we build a parameter-dependent SSM-reduced model that predicts global heteroclinic and local bifurcations in a Furuta pendulum under control with delay, and verify these predictions numerically. Under additional spatial discretization of the digital controller, we also obtain an SSM-reduced model that correctly reproduces a numerically and experimentally observed microchaotic attractor in the system.
{"title":"Data-driven modeling of global bifurcations and chaos in a mechanical system under delayed and quantized control","authors":"Giacomo Abbasciano , Balázs Endrész , Gábor Stépán , George Haller","doi":"10.1016/j.jsv.2026.119660","DOIUrl":"10.1016/j.jsv.2026.119660","url":null,"abstract":"<div><div>We illustrate how the recent theory of Spectral Submanifolds (SSM) can capture global bifurcations and complex dynamics in mechanical systems even under delay and spatial discretization. Specifically, we build a parameter-dependent SSM-reduced model that predicts global heteroclinic and local bifurcations in a Furuta pendulum under control with delay, and verify these predictions numerically. Under additional spatial discretization of the digital controller, we also obtain an SSM-reduced model that correctly reproduces a numerically and experimentally observed microchaotic attractor in the system.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"628 ","pages":"Article 119660"},"PeriodicalIF":4.9,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036175","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}
Bridge Weigh-in-Motion (B-WIM) systems provide vital traffic data for bridge design, management, and maintenance, yet conventional approaches often rely on bridge influence lines that are notoriously challenging to be identified accurately. While some model-independent approaches have been proposed, they typically estimate only partial parameters like axle loads, lacking the capability to simultaneously determine axle spacings. To address these limitations, this study proposes a model-free B-WIM methodology for simultaneous identification of vehicle axle loads and spacings using an influence line-free transmissibility-like index. This index, defined as the ratio of frequency-domain responses at the same location for two distinct vehicles, is analytically proven to equal the ratio of their moving load functions in the frequency domain, thereby eliminating the need for influence line estimation. Given the response of a reference vehicle with known axle configuration, this property enables the simultaneous identification of both axle loads and spacings. A Bayesian inference scheme is further developed to integrate multiple measurements and accommodate uncertainties stemming from measurement noise and modeling errors. Moreover, analytical likelihood function, gradients, and posterior covariances are derived to support efficient optimization scheme. Ultimately, numerical simulations and experimental studies validate the method’s accuracy and robustness under varying scenarios, without requiring influence line estimation.
{"title":"A model-free B-WIM scheme for simultaneously identifying vehicle axle load and spacing with transmissibility-like index","authors":"Teng-Teng Hao , Wang-Ji Yan , Meng-Kai Niu , Ka-Veng Yuen , Costas Papadimitriou","doi":"10.1016/j.jsv.2026.119637","DOIUrl":"10.1016/j.jsv.2026.119637","url":null,"abstract":"<div><div>Bridge Weigh-in-Motion (B-WIM) systems provide vital traffic data for bridge design, management, and maintenance, yet conventional approaches often rely on bridge influence lines that are notoriously challenging to be identified accurately. While some model-independent approaches have been proposed, they typically estimate only partial parameters like axle loads, lacking the capability to simultaneously determine axle spacings. To address these limitations, this study proposes a model-free B-WIM methodology for simultaneous identification of vehicle axle loads and spacings using an influence line-free transmissibility-like index. This index, defined as the ratio of frequency-domain responses at the same location for two distinct vehicles, is analytically proven to equal the ratio of their moving load functions in the frequency domain, thereby eliminating the need for influence line estimation. Given the response of a reference vehicle with known axle configuration, this property enables the simultaneous identification of both axle loads and spacings. A Bayesian inference scheme is further developed to integrate multiple measurements and accommodate uncertainties stemming from measurement noise and modeling errors. Moreover, analytical likelihood function, gradients, and posterior covariances are derived to support efficient optimization scheme. Ultimately, numerical simulations and experimental studies validate the method’s accuracy and robustness under varying scenarios, without requiring influence line estimation.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"628 ","pages":"Article 119637"},"PeriodicalIF":4.9,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079964","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}
Pub Date : 2026-04-28Epub Date: 2026-01-16DOI: 10.1016/j.jsv.2026.119664
Xueyi Jiang , Zhong-Rong Lu , Xuliang Lin , Jie Yuan , Li Wang , Dahao Yang
The effectiveness of Vibro-Impact Nonlinear Energy Sink cells (VI-NES cells) in suppressing multi-mode vibration is highly sensitive to contact stiffness, mass ratio, and impact gap, necessitating precise tuning of these parameters. This paper develops an event-driven sensitivity method to optimize a time-domain objective function, automatically obtaining cells’ parameters with approximately global optimized vibration suppression efficiency. First, the vibro-impact process between VI-NES cells and a host structure is regularized as a Hertzian model with linear contact stiffness and damping, yielding explicitly piecewise linear forces governed by contact-separation phase transitions. Subsequently, an event-driven time integration algorithm is developed to analyze dynamic responses by detecting transition points. Before and after the contact-separation transition points, the sensitivity affine relation is derived in detail, resulting in the time-domain response sensitivity with respect to mass and impact gap. Ultimately, the acquired response sensitivities and Tikhonov regularization are applied to optimize a time-domain objective function about VI-NES parameters, minimizing the dynamic vibration responses of the host structure. Numerical studies validate that the proposed method enhances the multi-mode vibration suppression performance of VI-NES cells, and clarifies the energy dissipation, targeted energy transfer, and coupling mechanics of VI-NES cells, offering an essential framework toward large-scale simulations and optimization of the host structure with VI-NES cells.
{"title":"An event-driven time-domain sensitivity method for optimizing parameters of vibro-impact NES cells to suppress multi-mode vibration","authors":"Xueyi Jiang , Zhong-Rong Lu , Xuliang Lin , Jie Yuan , Li Wang , Dahao Yang","doi":"10.1016/j.jsv.2026.119664","DOIUrl":"10.1016/j.jsv.2026.119664","url":null,"abstract":"<div><div>The effectiveness of Vibro-Impact Nonlinear Energy Sink cells (VI-NES cells) in suppressing multi-mode vibration is highly sensitive to contact stiffness, mass ratio, and impact gap, necessitating precise tuning of these parameters. This paper develops an event-driven sensitivity method to optimize a time-domain objective function, automatically obtaining cells’ parameters with approximately global optimized vibration suppression efficiency. First, the vibro-impact process between VI-NES cells and a host structure is regularized as a Hertzian model with linear contact stiffness and damping, yielding explicitly piecewise linear forces governed by contact-separation phase transitions. Subsequently, an event-driven time integration algorithm is developed to analyze dynamic responses by detecting transition points. Before and after the contact-separation transition points, the sensitivity affine relation is derived in detail, resulting in the time-domain response sensitivity with respect to mass and impact gap. Ultimately, the acquired response sensitivities and Tikhonov regularization are applied to optimize a time-domain objective function about VI-NES parameters, minimizing the dynamic vibration responses of the host structure. Numerical studies validate that the proposed method enhances the multi-mode vibration suppression performance of VI-NES cells, and clarifies the energy dissipation, targeted energy transfer, and coupling mechanics of VI-NES cells, offering an essential framework toward large-scale simulations and optimization of the host structure with VI-NES cells.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"628 ","pages":"Article 119664"},"PeriodicalIF":4.9,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036235","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}
Pub Date : 2026-04-28Epub Date: 2026-01-29DOI: 10.1016/j.jsv.2026.119675
Hufei Li , Yuan Liu , Sha Wei , Hu Ding , Li-Qun Chen
This study investigates bimodal analysis of random vibrations in fluid-conveying pipes by considering gyroscopic effects, contrasting with previous studies that relied on single modal analysis by first-order Galerkin truncation models. A high-dimensional coupled stochastic differential equation for the pipe system is established to capture complex modal interactions and nonlinear coupling effects. The right boundary of the Itô equation obtained from the pipe system with the gyroscopic term is proven to be the exit boundary. Through the stochastic averaging method for quasi non-integrable Hamilton systems, a time-varying Fokker-Planck-Kolmogorov (FPK) equation is derived and numerically solved to calculate the transient probability density function of the system total energy. The results accuracy is validated by comparing results with the Monte Carlo approach in two ways: the exact expression and numerical integration results of the diffusion coefficient. The variation of transient probability density functions with time is studied over a certain period, and the effects of noise intensity, fluid speed and pipe length on probability density functions of the system total energy are investigated. Numerical examples show that compared to the results of single modal analysis, this approach improves the prediction accuracy and accurately captures the random vibration characteristics of the fluid-conveying pipe.
{"title":"Bimodal analysis on random vibration of pipes conveying fluid","authors":"Hufei Li , Yuan Liu , Sha Wei , Hu Ding , Li-Qun Chen","doi":"10.1016/j.jsv.2026.119675","DOIUrl":"10.1016/j.jsv.2026.119675","url":null,"abstract":"<div><div>This study investigates bimodal analysis of random vibrations in fluid-conveying pipes by considering gyroscopic effects, contrasting with previous studies that relied on single modal analysis by first-order Galerkin truncation models. A high-dimensional coupled stochastic differential equation for the pipe system is established to capture complex modal interactions and nonlinear coupling effects. The right boundary of the Itô equation obtained from the pipe system with the gyroscopic term is proven to be the exit boundary. Through the stochastic averaging method for quasi non-integrable Hamilton systems, a time-varying Fokker-Planck-Kolmogorov (FPK) equation is derived and numerically solved to calculate the transient probability density function of the system total energy. The results accuracy is validated by comparing results with the Monte Carlo approach in two ways: the exact expression and numerical integration results of the diffusion coefficient. The variation of transient probability density functions with time is studied over a certain period, and the effects of noise intensity, fluid speed and pipe length on probability density functions of the system total energy are investigated. Numerical examples show that compared to the results of single modal analysis, this approach improves the prediction accuracy and accurately captures the random vibration characteristics of the fluid-conveying pipe.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"628 ","pages":"Article 119675"},"PeriodicalIF":4.9,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189977","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}
Pub Date : 2026-04-28Epub Date: 2026-01-09DOI: 10.1016/j.jsv.2026.119643
Khaled F. Aljanaideh , Isam Al-Darabsah , Mohammad Al Janaideh
Sensor-to-sensor transmissibility operators are mathematical objects that relate two subsets of system outputs. A transmissibility operator can be used along with one subset of outputs to predict the other subset of outputs of the underlying system without knowledge of a model of the underlying system or the excitation signal acting on it. Transmissibility operators have been used in applications including fault detection, virtual sensing, state estimation, and system identification. Standard transmissibility formulations assume that the number of transmissibility inputs equals the dimension of the excitation signal acting on the underlying system. However, since transmissibilities operate in environments with unknown inputs, estimating the dimension of the excitation signal can be challenging. Moreover, numerical evidence from previous research shows that the predicted outputs obtained using transmissibility operators become more accurate as the number of transmissibility inputs increases. In this paper, we introduce a more general mathematical representation of transmissibility operators that allows the number of transmissibility inputs to exceed the excitation dimension, hence the term generalized transmissibility operators. We further show that the determinant of the difference between two generalized transmissibility operators constructed between the same outputs but under different input locations can be used to determine the poles of the underlying system, outperforming existing time- and frequency-domain transmissibility-based modal estimation techniques. The framework is validated through numerical pole estimation of a mechanical structure and experimental soft sensing of an acoustic system, demonstrating improved accuracy and robustness over existing approaches.
{"title":"Generalized sensor-to-sensor transmissibility operators: Theory, identification, and applications in soft sensing and modal estimation","authors":"Khaled F. Aljanaideh , Isam Al-Darabsah , Mohammad Al Janaideh","doi":"10.1016/j.jsv.2026.119643","DOIUrl":"10.1016/j.jsv.2026.119643","url":null,"abstract":"<div><div>Sensor-to-sensor transmissibility operators are mathematical objects that relate two subsets of system outputs. A transmissibility operator can be used along with one subset of outputs to predict the other subset of outputs of the underlying system without knowledge of a model of the underlying system or the excitation signal acting on it. Transmissibility operators have been used in applications including fault detection, virtual sensing, state estimation, and system identification. Standard transmissibility formulations assume that the number of transmissibility inputs equals the dimension of the excitation signal acting on the underlying system. However, since transmissibilities operate in environments with unknown inputs, estimating the dimension of the excitation signal can be challenging. Moreover, numerical evidence from previous research shows that the predicted outputs obtained using transmissibility operators become more accurate as the number of transmissibility inputs increases. In this paper, we introduce a more general mathematical representation of transmissibility operators that allows the number of transmissibility inputs to exceed the excitation dimension, hence the term <em>generalized</em> transmissibility operators. We further show that the determinant of the difference between two generalized transmissibility operators constructed between the same outputs but under different input locations can be used to determine the poles of the underlying system, outperforming existing time- and frequency-domain transmissibility-based modal estimation techniques. The framework is validated through numerical pole estimation of a mechanical structure and experimental soft sensing of an acoustic system, demonstrating improved accuracy and robustness over existing approaches.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"628 ","pages":"Article 119643"},"PeriodicalIF":4.9,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036556","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}
Pub Date : 2026-04-28Epub Date: 2026-01-09DOI: 10.1016/j.jsv.2026.119654
Devavrit Maharshi , Michael I. Friswell , Barun Pratiher
The demand for lightweight, high-strength rotors with reliable vibration stability is rapidly increasing across aerospace, automotive, turbomachinery, and energy systems. Functionally graded graphene platelet-reinforced composites (FG-GPLRCs) offer a promising solution by enabling tailored stiffness and damping, achieving both weight reduction and enhanced dynamic performance. This study presents a novel analysis of the nonlinear dynamics of axially restrained FG-GPLRC multi-disk shafts under imbalance excitation, explicitly accounting for large-deflection behavior and multi-disk imbalance. The governing equations of the composite shaft-disk system are first derived and reduced using a fundamental-mode Galerkin approximation. The resulting reduced-order model is then analyzed via the method of multiple scales to obtain analytical expressions for the natural frequencies, which are subsequently validated through finite element simulations in ANSYS, confirming predictive accuracy. The investigation systematically examines how four reinforcement patterns, graphene platelet weight fraction, number of layers, and geometric ratios influence the vibration behavior and stability of the system. Results indicate that increasing the graphene platelet content from 0% to 2.5% substantially enhances performance, with natural frequencies rising by 170%-270% and critical damping by nearly 300%, while simultaneously reducing critical eccentricity and jump-down length by 80% and 8%, respectively. The reinforcement pattern and the number of graphene layers further shift frequencies by up to 37%, modify critical damping by 25%, affect jump-down length by 18%, and alter critical eccentricity by up to 30%. Overall, the findings highlight the potential of FG-GPLRC shafts for stable jump-free operation and the reliable design of high-speed rotor systems.
{"title":"Dynamic modeling and stability assessment of functionally graded graphene platelet-reinforced composite multi-Disk rotors","authors":"Devavrit Maharshi , Michael I. Friswell , Barun Pratiher","doi":"10.1016/j.jsv.2026.119654","DOIUrl":"10.1016/j.jsv.2026.119654","url":null,"abstract":"<div><div>The demand for lightweight, high-strength rotors with reliable vibration stability is rapidly increasing across aerospace, automotive, turbomachinery, and energy systems. Functionally graded graphene platelet-reinforced composites (FG-GPLRCs) offer a promising solution by enabling tailored stiffness and damping, achieving both weight reduction and enhanced dynamic performance. This study presents a novel analysis of the nonlinear dynamics of axially restrained FG-GPLRC multi-disk shafts under imbalance excitation, explicitly accounting for large-deflection behavior and multi-disk imbalance. The governing equations of the composite shaft-disk system are first derived and reduced using a fundamental-mode Galerkin approximation. The resulting reduced-order model is then analyzed via the method of multiple scales to obtain analytical expressions for the natural frequencies, which are subsequently validated through finite element simulations in ANSYS, confirming predictive accuracy. The investigation systematically examines how four reinforcement patterns, graphene platelet weight fraction, number of layers, and geometric ratios influence the vibration behavior and stability of the system. Results indicate that increasing the graphene platelet content from 0% to 2.5% substantially enhances performance, with natural frequencies rising by 170%-270% and critical damping by nearly 300%, while simultaneously reducing critical eccentricity and jump-down length by 80% and 8%, respectively. The reinforcement pattern and the number of graphene layers further shift frequencies by up to 37%, modify critical damping by 25%, affect jump-down length by 18%, and alter critical eccentricity by up to 30%. Overall, the findings highlight the potential of FG-GPLRC shafts for stable jump-free operation and the reliable design of high-speed rotor systems.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"628 ","pages":"Article 119654"},"PeriodicalIF":4.9,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036557","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}
Pub Date : 2026-04-28Epub Date: 2026-01-14DOI: 10.1016/j.jsv.2026.119639
Shiyi Mei , Colin Caprani , Daniel Cantero
A separation-of-variable dynamic stiffness method (SOV-DSM) is proposed for the free vibration analysis of an thin orthotropic rectangular plate with general homogeneous boundary conditions. Firstly, the extended SOV solution satisfying Rayleigh’s principle is extended to handle arbitrary boundary conditions and then applied to develop closed-form dynamic stiffness formulations. Then, an enhanced Wittrick-Williams (W-W) algorithm is used to solve the eigenvalue problem rather than solving the highly nonlinear eigenvalue equations. The J0 count problem involved in applying the W-W algorithm is addressed by providing an explicit and closed-form expression for the J0 term based on the characteristics of the SOV solution. Furthermore, a numerical technique is provided to calculate the mode shape of the plate with any arbitrary boundary conditions. The accuracy of the proposed method is validated through numerical experiments by comparison with other analytical solutions.
{"title":"A separation-of-variable dynamic stiffness method for the free vibration of thin orthotropic rectangular plates with general homogeneous boundary conditions","authors":"Shiyi Mei , Colin Caprani , Daniel Cantero","doi":"10.1016/j.jsv.2026.119639","DOIUrl":"10.1016/j.jsv.2026.119639","url":null,"abstract":"<div><div>A separation-of-variable dynamic stiffness method (SOV-DSM) is proposed for the free vibration analysis of an thin orthotropic rectangular plate with general homogeneous boundary conditions. Firstly, the extended SOV solution satisfying Rayleigh’s principle is extended to handle arbitrary boundary conditions and then applied to develop closed-form dynamic stiffness formulations. Then, an enhanced Wittrick-Williams (W-W) algorithm is used to solve the eigenvalue problem rather than solving the highly nonlinear eigenvalue equations. The <em>J</em><sub>0</sub> count problem involved in applying the W-W algorithm is addressed by providing an explicit and closed-form expression for the <em>J</em><sub>0</sub> term based on the characteristics of the SOV solution. Furthermore, a numerical technique is provided to calculate the mode shape of the plate with any arbitrary boundary conditions. The accuracy of the proposed method is validated through numerical experiments by comparison with other analytical solutions.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"628 ","pages":"Article 119639"},"PeriodicalIF":4.9,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036186","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}
Pub Date : 2026-04-28Epub Date: 2026-01-07DOI: 10.1016/j.jsv.2026.119642
Sylvain C. Humbert , Alessandro Orchini
The impacts of non-uniform flame response distributions on the stability of azimuthal thermoacoustic modes in annular combustors are investigated theoretically and illustrated in an experimental annular combustor test-rig with electroacoustic feedback. First, we exploit analytical results from an existing reduced-order model to establish and apply a general passive control strategy based on flame response staging to mitigate thermoacoustic instabilities stemming from both degenerate and non-degenerate eigenvalues. By means of a suitable pattern, an acoustics-flame response interaction that has a destabilising effect in the baseline symmetric configuration can be suppressed or turned into a stabilising interaction. For a mode pair whose degeneracy is lifted by the flame response staging pattern, our mitigation strategy exploits the presence of symmetry-breaking-induced exceptional points, which were recently identified in a previous study. The mitigation rules obtained when considering a degenerate or a non-degenerate mode in an isolated fashion are finally combined to establish a multi-mode strategy to prevent all azimuthal modes from being linearly unstable. The mitigation strategy is devised using a low-order model, and validated using an existing experimentally-determined state-space model and experiments in an electroacoustic feedback annular combustor test-rig. In addition, we show that if accurate estimates of the acoustic and thermoacoustic eigenvalues in the reference (symmetric) configuration are available, they can be exploited to calibrate the low-order model and then analytically predict the eigenvalues in the asymmetric configurations with good accuracy.
{"title":"Suppressing azimuthal thermoacoustic instabilities through symmetry-breaking flame response staging and exceptional points","authors":"Sylvain C. Humbert , Alessandro Orchini","doi":"10.1016/j.jsv.2026.119642","DOIUrl":"10.1016/j.jsv.2026.119642","url":null,"abstract":"<div><div>The impacts of non-uniform flame response distributions on the stability of azimuthal thermoacoustic modes in annular combustors are investigated theoretically and illustrated in an experimental annular combustor test-rig with electroacoustic feedback. First, we exploit analytical results from an existing reduced-order model to establish and apply a general passive control strategy based on flame response staging to mitigate thermoacoustic instabilities stemming from both degenerate and non-degenerate eigenvalues. By means of a suitable pattern, an acoustics-flame response interaction that has a destabilising effect in the baseline symmetric configuration can be suppressed or turned into a stabilising interaction. For a mode pair whose degeneracy is lifted by the flame response staging pattern, our mitigation strategy exploits the presence of symmetry-breaking-induced exceptional points, which were recently identified in a previous study. The mitigation rules obtained when considering a degenerate or a non-degenerate mode in an isolated fashion are finally combined to establish a multi-mode strategy to prevent all azimuthal modes from being linearly unstable. The mitigation strategy is devised using a low-order model, and validated using an existing experimentally-determined state-space model and experiments in an electroacoustic feedback annular combustor test-rig. In addition, we show that if accurate estimates of the acoustic and thermoacoustic eigenvalues in the reference (symmetric) configuration are available, they can be exploited to calibrate the low-order model and then analytically predict the eigenvalues in the asymmetric configurations with good accuracy.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"628 ","pages":"Article 119642"},"PeriodicalIF":4.9,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145986744","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}
Pub Date : 2026-04-14Epub Date: 2026-01-12DOI: 10.1016/j.jsv.2026.119659
M. Trabelssi , S. El-Borgi , N. Challamel , M.I. Friswell
The present study investigates bandgap formation in micromorphic metamaterial Euler-Bernoulli beams, with the problem also modeled using a nonlocal strain gradient framework. Both models are mathematically well-posed, sharing identical governing equations but differing in the definiteness of their potential energy. Multiple oscillators, arranged in two distinct configurations according to the local resonance principle, are employed to realize a double bandgap structure. Application of Hamilton’s principle yields the non-dimensional governing equations of motion, expressed as a sixth-order system with corresponding boundary conditions. Bandgap edge frequencies are determined from wave dispersion analysis in an infinitely long beam by means of periodic unit cell modeling. Dispersion relations derived through homogenization and transfer matrix methods are consistent with each other and with previously established results. Two homogenization approaches are examined: a one-field displacement-based formulation, which neglects nonlocal oscillator inertia and fails to guarantee asymptotic consistency when the nonlocal and strain gradient parameters are equal and large; and a two-field formulation, which resolves this limitation and preserves consistency. Dispersion curves obtained from both homogenization schemes are compared with those from the transfer matrix method to assess accuracy. The dispersion characteristics derived from the infinite medium formulation are further validated by frequency response functions of a finite-length nanobeam, demonstrating agreement between spectral predictions and bounded system dynamics. Finally, a parametric study explores the influence of key parameters, including the nonlocal and strain gradient coefficients, unit cell length, and resonator-to-unit-cell mass ratio, on bandgap formation in metamaterial beams.
{"title":"Double bandgap formation in a locally resonant metamaterial micromorphic beam","authors":"M. Trabelssi , S. El-Borgi , N. Challamel , M.I. Friswell","doi":"10.1016/j.jsv.2026.119659","DOIUrl":"10.1016/j.jsv.2026.119659","url":null,"abstract":"<div><div>The present study investigates bandgap formation in micromorphic metamaterial Euler-Bernoulli beams, with the problem also modeled using a nonlocal strain gradient framework. Both models are mathematically well-posed, sharing identical governing equations but differing in the definiteness of their potential energy. Multiple oscillators, arranged in two distinct configurations according to the local resonance principle, are employed to realize a double bandgap structure. Application of Hamilton’s principle yields the non-dimensional governing equations of motion, expressed as a sixth-order system with corresponding boundary conditions. Bandgap edge frequencies are determined from wave dispersion analysis in an infinitely long beam by means of periodic unit cell modeling. Dispersion relations derived through homogenization and transfer matrix methods are consistent with each other and with previously established results. Two homogenization approaches are examined: a one-field displacement-based formulation, which neglects nonlocal oscillator inertia and fails to guarantee asymptotic consistency when the nonlocal and strain gradient parameters are equal and large; and a two-field formulation, which resolves this limitation and preserves consistency. Dispersion curves obtained from both homogenization schemes are compared with those from the transfer matrix method to assess accuracy. The dispersion characteristics derived from the infinite medium formulation are further validated by frequency response functions of a finite-length nanobeam, demonstrating agreement between spectral predictions and bounded system dynamics. Finally, a parametric study explores the influence of key parameters, including the nonlocal and strain gradient coefficients, unit cell length, and resonator-to-unit-cell mass ratio, on bandgap formation in metamaterial beams.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"627 ","pages":"Article 119659"},"PeriodicalIF":4.9,"publicationDate":"2026-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024964","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}
Pub Date : 2026-04-14Epub Date: 2026-01-14DOI: 10.1016/j.jsv.2026.119661
Paweł Olejnik, Yared D. Desta
This work investigates the tribo-structural dynamics of a slender post-buckled beam interacting with a translating surface through rolling, sticking and slipping at a line contact. Extreme slenderness, strong geometric nonlinearity and compliant boundary conditions create a highly sensitive frictional environment in which small variations in contact kinematics generate measurable near-field acoustic emission. A dedicated experimental setup was developed to synchronously record beam motion, roller rotation, contact forces and near-field pressure signatures.
A nonlinear mechanical model is formulated using Euler–Bernoulli kinematics with von Kármán strain, Hertzian normal contact and a smooth velocity-dependent friction law reproducing rolling and stick–slip transitions. Motivated by experimental observations that near-field acoustic activity correlates with cycle-to-cycle slip variability, a compact phenomenological modulation acting solely on the kinetic friction coefficient is introduced. The measured near-field signal is treated as a bounded, non-energetic observable and used as a diagnostic descriptor of unresolved microscale contact fluctuations, without implying physical acoustic feedback.
Coupled structural–acoustic finite-element simulations reproduce changes in stick–slip periodicity, effective damping and the tonal components of the measured acoustic response. The resulting framework provides an energetically admissible diagnostic perspective on tribo-acoustic behaviour in slender post-buckled structures with rolling contact and addresses an under-explored relationship between near-field sound and frictional sliding variability.
{"title":"Phenomenological friction modulation and near-field acoustic signatures in a slender post-buckled beam with rolling–stick–slip contact","authors":"Paweł Olejnik, Yared D. Desta","doi":"10.1016/j.jsv.2026.119661","DOIUrl":"10.1016/j.jsv.2026.119661","url":null,"abstract":"<div><div>This work investigates the tribo-structural dynamics of a slender post-buckled beam interacting with a translating surface through rolling, sticking and slipping at a line contact. Extreme slenderness, strong geometric nonlinearity and compliant boundary conditions create a highly sensitive frictional environment in which small variations in contact kinematics generate measurable near-field acoustic emission. A dedicated experimental setup was developed to synchronously record beam motion, roller rotation, contact forces and near-field pressure signatures.</div><div>A nonlinear mechanical model is formulated using Euler–Bernoulli kinematics with von Kármán strain, Hertzian normal contact and a smooth velocity-dependent friction law reproducing rolling and stick–slip transitions. Motivated by experimental observations that near-field acoustic activity correlates with cycle-to-cycle slip variability, a compact phenomenological modulation acting solely on the kinetic friction coefficient is introduced. The measured near-field signal is treated as a bounded, non-energetic observable and used as a diagnostic descriptor of unresolved microscale contact fluctuations, without implying physical acoustic feedback.</div><div>Coupled structural–acoustic finite-element simulations reproduce changes in stick–slip periodicity, effective damping and the tonal components of the measured acoustic response. The resulting framework provides an energetically admissible diagnostic perspective on tribo-acoustic behaviour in slender post-buckled structures with rolling contact and addresses an under-explored relationship between near-field sound and frictional sliding variability.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"627 ","pages":"Article 119661"},"PeriodicalIF":4.9,"publicationDate":"2026-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981905","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号