Pub Date : 2025-02-05DOI: 10.1016/j.ijmecsci.2025.110044
Hao-Bo Qi , Shi-Wang Fan , Mu Jiang , Zhu Tong , Badreddine Assouar , Yue-Sheng Wang
Achieving effective sound insulation across a broadband range at low frequency while ensuring sufficient ventilation remains a significant challenge in the field of acoustic engineering, as there exist complex trade-offs in attenuation capacity, operating frequency, and opening size. Here, a double Archimedean spiral structure is proposed and then optimized using genetic algorithms. The sparse design, featuring ventilated channels on both sides of the unit, significantly expands the operational frequency range, effectively blocking over 80 % of incident energy within the 546–1575 Hz range. Its working mechanism can be attributed to the Fano-like resonance effect, which is further revealed by employing a mechanical analogy based on the spring-mass model. Moreover, the addition of foams and a reconfigurable modular assembly enhances both broadband sound reduction and flexibility. Consistency between numerical simulations and experimental results validate the potential for this approach in applications of ventilated acoustic insulation, offering advantageous theoretical and practical perspectives.
{"title":"Low-frequency broadband metamaterials for ventilated acoustic insulation","authors":"Hao-Bo Qi , Shi-Wang Fan , Mu Jiang , Zhu Tong , Badreddine Assouar , Yue-Sheng Wang","doi":"10.1016/j.ijmecsci.2025.110044","DOIUrl":"10.1016/j.ijmecsci.2025.110044","url":null,"abstract":"<div><div>Achieving effective sound insulation across a broadband range at low frequency while ensuring sufficient ventilation remains a significant challenge in the field of acoustic engineering, as there exist complex trade-offs in attenuation capacity, operating frequency, and opening size. Here, a double Archimedean spiral structure is proposed and then optimized using genetic algorithms. The sparse design, featuring ventilated channels on both sides of the unit, significantly expands the operational frequency range, effectively blocking over 80 % of incident energy within the 546–1575 Hz range. Its working mechanism can be attributed to the Fano-like resonance effect, which is further revealed by employing a mechanical analogy based on the spring-mass model. Moreover, the addition of foams and a reconfigurable modular assembly enhances both broadband sound reduction and flexibility. Consistency between numerical simulations and experimental results validate the potential for this approach in applications of ventilated acoustic insulation, offering advantageous theoretical and practical perspectives.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"289 ","pages":"Article 110044"},"PeriodicalIF":7.1,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-02-05DOI: 10.1016/j.ijmecsci.2025.110037
Fengrui Liu , Tatsuro Terakawa , Ji Lin , Masaharu Komori
Origami-inspired deployable structures have extreme compactness and design flexibility, suitable for aerospace structures, disaster relief robots, and medical devices. However, due to the lack of rigid-foldability, many origami applications rely on soft materials, limiting their load-bearing capacity and range of applications. To address this issue, this study proposes an origami design called Foldable Cube origami (FC-ori), which allows a cube to be rigidly folded into a square. By adding a translational degree of freedom along the rotational axis on some creases, FC-ori effectively mitigates the effects of thickness while preserving both rigid and flat foldability. By attaching various magnets and springs, an FC-ori unit can exhibit programmable multistability. Utilizing these units, we designed a modular, deployable mobile robot that can adapt to various terrains and tasks by transforming its configuration, demonstrating the potential of FC-ori in rigid origami applications.
{"title":"Design of modular deployable structure with programmable multistability","authors":"Fengrui Liu , Tatsuro Terakawa , Ji Lin , Masaharu Komori","doi":"10.1016/j.ijmecsci.2025.110037","DOIUrl":"10.1016/j.ijmecsci.2025.110037","url":null,"abstract":"<div><div>Origami-inspired deployable structures have extreme compactness and design flexibility, suitable for aerospace structures, disaster relief robots, and medical devices. However, due to the lack of rigid-foldability, many origami applications rely on soft materials, limiting their load-bearing capacity and range of applications. To address this issue, this study proposes an origami design called Foldable Cube origami (FC-ori), which allows a cube to be rigidly folded into a square. By adding a translational degree of freedom along the rotational axis on some creases, FC-ori effectively mitigates the effects of thickness while preserving both rigid and flat foldability. By attaching various magnets and springs, an FC-ori unit can exhibit programmable multistability. Utilizing these units, we designed a modular, deployable mobile robot that can adapt to various terrains and tasks by transforming its configuration, demonstrating the potential of FC-ori in rigid origami applications.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"288 ","pages":"Article 110037"},"PeriodicalIF":7.1,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amorphous-crystal nanomultilayers (ACNMs) exhibit outstanding mechanical properties, but the micro-mechanisms responsible for the enhancement of their mechanical performance remain incompletely understood. Molecular dynamics (MD) simulations were performed on the tensile processes of NiTiAl ACNMs to examine the microstructure evolutions during deformation in crystals, amorphous (MGs), and crystal-amorphous interfaces (CAIs). ACNMs increase in strength and decrease in plasticity with decreasing interface spacing. The MGs layer can accommodate larger strains. The intense competition among shear transformation zones (STZs) mitigates strain localization in MGs and boosts the plasticity of ACNMs. In the crystal layer, the main plastic deformation mechanism is that FCC clusters are disrupted and converted into other MGs clusters. As the interface spacing decreases, the geometrically constrained dispersion of STZs boosts material strength. The self-developed Largest Standard Cluster Analysis (LaSCA) method was employed to accurately depict the microstructure evolution of CAIs. The CAIs are responsible for strain transmission and induce dislocation accumulation in their vicinity, leading to localized strain. This study elucidates the microstructural changes in ACNMs during tensile deformation, offering insights for optimizing their mechanical properties through interface spacing design.
{"title":"Micro-mechanism of mechanical enhancement of NiTiAl amorphous-crystal nanomultilayers","authors":"Yuanwei Pu , Yongchao Liang , Yu Zhou , Qian Chen , Tinghong Gao , Lili Zhou , Zean Tian","doi":"10.1016/j.ijmecsci.2025.110020","DOIUrl":"10.1016/j.ijmecsci.2025.110020","url":null,"abstract":"<div><div>Amorphous-crystal nanomultilayers (ACNMs) exhibit outstanding mechanical properties, but the micro-mechanisms responsible for the enhancement of their mechanical performance remain incompletely understood. Molecular dynamics (MD) simulations were performed on the tensile processes of NiTiAl ACNMs to examine the microstructure evolutions during deformation in crystals, amorphous (MGs), and crystal-amorphous interfaces (CAIs). ACNMs increase in strength and decrease in plasticity with decreasing interface spacing. The MGs layer can accommodate larger strains. The intense competition among shear transformation zones (STZs) mitigates strain localization in MGs and boosts the plasticity of ACNMs. In the crystal layer, the main plastic deformation mechanism is that FCC clusters are disrupted and converted into other MGs clusters. As the interface spacing decreases, the geometrically constrained dispersion of STZs boosts material strength. The self-developed Largest Standard Cluster Analysis (LaSCA) method was employed to accurately depict the microstructure evolution of CAIs. The CAIs are responsible for strain transmission and induce dislocation accumulation in their vicinity, leading to localized strain. This study elucidates the microstructural changes in ACNMs during tensile deformation, offering insights for optimizing their mechanical properties through interface spacing design.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"288 ","pages":"Article 110020"},"PeriodicalIF":7.1,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dielectric elastomer tubular actuators (DETA) as a new type of smart material actuator, has attracted wide attention in recent years. Its basic working principle is to use the deformation generated by dielectric elastomers (DEs) under the electric field to achieve the actuation function. Compared with the traditional actuators, DETA has the advantages of high energy density, fast response, simple structure, lightweight, soft and large deformation. In engineering applications, good structural design can improve the efficiency of actuation, reduce energy loss and prolong service life. The purpose of this paper is to explore the electromechanical coupling principle of DETA. Based on the Absolute Nodal Coordinate Formulation (ANCF), we use the electromechanically coupled 8-node hexahedral element, and consider the viscoelastic properties of the material to derive the dynamic equations of the flexible system containing DETA. Subsequently, the static and dynamic behaviors of the system are studied, and the correctness and validity of the method proposed in this work are verified by comparing with the experimental results. The research in this paper not only enriches the modeling and theoretical analysis of DEs, but also provides new ideas and methods for its application.
{"title":"Dynamic modeling and analysis for dielectric elastomer tube actuators","authors":"Yuqing Guo , Liang Li , Dingguo Zhang , Wei-Hsin Liao","doi":"10.1016/j.ijmecsci.2025.109994","DOIUrl":"10.1016/j.ijmecsci.2025.109994","url":null,"abstract":"<div><div>Dielectric elastomer tubular actuators (DETA) as a new type of smart material actuator, has attracted wide attention in recent years. Its basic working principle is to use the deformation generated by dielectric elastomers (DEs) under the electric field to achieve the actuation function. Compared with the traditional actuators, DETA has the advantages of high energy density, fast response, simple structure, lightweight, soft and large deformation. In engineering applications, good structural design can improve the efficiency of actuation, reduce energy loss and prolong service life. The purpose of this paper is to explore the electromechanical coupling principle of DETA. Based on the Absolute Nodal Coordinate Formulation (ANCF), we use the electromechanically coupled 8-node hexahedral element, and consider the viscoelastic properties of the material to derive the dynamic equations of the flexible system containing DETA. Subsequently, the static and dynamic behaviors of the system are studied, and the correctness and validity of the method proposed in this work are verified by comparing with the experimental results. The research in this paper not only enriches the modeling and theoretical analysis of DEs, but also provides new ideas and methods for its application.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"288 ","pages":"Article 109994"},"PeriodicalIF":7.1,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143349971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reducing low-frequency vibration and sound radiation in lightweight sandwich structures remains a significant challenge due to the inherently long wavelength of low-frequency waves. In this study, we proposed a novel metamaterial sandwich plate with compressional-torsional coupling inertial amplification resonators to effectively attenuate low-frequency vibration and suppress sound radiation. The sandwich plate is integrally fabricated by 3D printing technology. A theoretical model for bandgap prediction is developed using Hamilton's principle. Theoretical, numerical, and experimental results converge to demonstrate that the proposed metamaterial sandwich plate exhibits superior low-frequency bandgap performance while ensuring the lightweight and compactness of the structure. The bandgap starting frequency of the compressional-torsional coupling resonator is 45 % lower than that of the conventional resonator, despite having identical mass and stiffness. Moreover, for the same bandgap starting frequency and stiffness, its mass is only 30 % of that of the conventional counterpart. Crucially, it also occupies significantly less space compared to the lever-type inertial amplification local resonator. This work introduces a promising strategy for the reduction of low-frequency vibration in engineering applications.
{"title":"Vibro-acoustic suppression in metamaterial sandwich plate using compressional-torsional coupling resonator","authors":"Rui Zhang , Wei Ding , Hao Liu , Peicheng Feng , Weizhe Ding , Tianning Chen , Jian Zhu","doi":"10.1016/j.ijmecsci.2025.110039","DOIUrl":"10.1016/j.ijmecsci.2025.110039","url":null,"abstract":"<div><div>Reducing low-frequency vibration and sound radiation in lightweight sandwich structures remains a significant challenge due to the inherently long wavelength of low-frequency waves. In this study, we proposed a novel metamaterial sandwich plate with compressional-torsional coupling inertial amplification resonators to effectively attenuate low-frequency vibration and suppress sound radiation. The sandwich plate is integrally fabricated by 3D printing technology. A theoretical model for bandgap prediction is developed using Hamilton's principle. Theoretical, numerical, and experimental results converge to demonstrate that the proposed metamaterial sandwich plate exhibits superior low-frequency bandgap performance while ensuring the lightweight and compactness of the structure. The bandgap starting frequency of the compressional-torsional coupling resonator is 45 % lower than that of the conventional resonator, despite having identical mass and stiffness. Moreover, for the same bandgap starting frequency and stiffness, its mass is only 30 % of that of the conventional counterpart. Crucially, it also occupies significantly less space compared to the lever-type inertial amplification local resonator. This work introduces a promising strategy for the reduction of low-frequency vibration in engineering applications.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"288 ","pages":"Article 110039"},"PeriodicalIF":7.1,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143349972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-02-02DOI: 10.1016/j.ijmecsci.2025.110036
Pengpeng Liu, Jie Tang, Yang Guo, Yinghui Li
In this paper, a cross-well dynamics model of bistable composite panels in centrifugal environments is proposed. The external excitation applied at the four corners is assumed to be a uniformly distributed harmonic acceleration. Nonlinear equations are derived by combining geometric nonlinearity, thermal stresses, and centrifugal effects with the first-order shear deformation theory, and are expressed in terms of curvature. Additionally, the maximum Lyapunov exponent is used to classify vibration types. Observations of periodic and chaotic snap-throughs are categorized into vibration type domains. To facilitate understanding, bifurcation diagrams, phase portraits, time histories, and Poincaré maps are presented for representative operating conditions. The effects of centrifugal environments, external excitation amplitude, and frequency on snap-through behavior are thoroughly investigated. The results show that there exists a critical static angular velocity, beyond which the panel cannot maintain bistability, and indicate that snap-through behavior in bistable panels is caused by negative stiffness due to residual thermal stresses. Bistable composite panels exhibit both forward and backward bouncing. Furthermore, three types of frequencies are identified: upper Stable I frequency, lower Stable II frequency, and snap-through frequency. It is also noted that the impact of angular velocity on these frequencies is not uniform. When the external excitation frequency approaches one stable state frequency, it can destabilize the configuration, causing vibrations to occur in the other configuration.
{"title":"Snap-through behaviors of bistable composite panel in centrifugal environments","authors":"Pengpeng Liu, Jie Tang, Yang Guo, Yinghui Li","doi":"10.1016/j.ijmecsci.2025.110036","DOIUrl":"10.1016/j.ijmecsci.2025.110036","url":null,"abstract":"<div><div>In this paper, a cross-well dynamics model of bistable composite panels in centrifugal environments is proposed. The external excitation applied at the four corners is assumed to be a uniformly distributed harmonic acceleration. Nonlinear equations are derived by combining geometric nonlinearity, thermal stresses, and centrifugal effects with the first-order shear deformation theory, and are expressed in terms of curvature. Additionally, the maximum Lyapunov exponent is used to classify vibration types. Observations of periodic and chaotic snap-throughs are categorized into vibration type domains. To facilitate understanding, bifurcation diagrams, phase portraits, time histories, and Poincaré maps are presented for representative operating conditions. The effects of centrifugal environments, external excitation amplitude, and frequency on snap-through behavior are thoroughly investigated. The results show that there exists a critical static angular velocity, beyond which the panel cannot maintain bistability, and indicate that snap-through behavior in bistable panels is caused by negative stiffness due to residual thermal stresses. Bistable composite panels exhibit both forward and backward bouncing. Furthermore, three types of frequencies are identified: upper Stable I frequency, lower Stable II frequency, and snap-through frequency. It is also noted that the impact of angular velocity on these frequencies is not uniform. When the external excitation frequency approaches one stable state frequency, it can destabilize the configuration, causing vibrations to occur in the other configuration.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"288 ","pages":"Article 110036"},"PeriodicalIF":7.1,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143295505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-02-02DOI: 10.1016/j.ijmecsci.2025.110024
Wei Cai , Jingyang Xiang , Guojun Dong , Kee-hung Lai , Marian Wiercigroch
Slender shafts have wide application on the aerospace, automotive and medical devices. However, they are prone to bending deformation during cutting process due to their low rigidity, resulting in poor machining accuracy and efficiency. A parallel multidirectional cutting (PMC) method is proposed using two tools to simultaneously cut the workpiece in forward or reverse directions contributing to overcome the problem of large deflections of these shafts. The main concept and PMC shared and unshared cutting modes are elucidated. An analytical model for PMC is established including chip geometry model, cutting force model and workpiece deflection feedback model. Given tool geometry, feed and depth of cut, chip load is accurately calculated using cutting edge discretization. The Johnson-Cook constitutive model is used to determine shear stress and shear force on the primary shear plane, and therefore the three-dimensional cutting force is obtained. The force condition of the workpiece is analysed under two clamping methods and the deformation of the workpiece is calculated and feed back into the model. On this basis, the influencing mechanism of cutting force, cutting power, cutting temperature and machining error of PMC is explored under different cutting modes, machined shaft geometry, tool parameters and cutting parameters. The smaller-the-better characteristic of Taguchi's method and signal-to-noise ratio are used to analyse the effect of cutting parameters on the PMC performance. Furthermore, an experimental validation is conducted to verify the cutting power, temperature, and diameter errors obtained by the proposed model, and the result shows a strong correlation with simulation predictions. The proposed method significantly improves machining precision and efficiency, with promising applications in high-precision manufacturing industries such as aerospace and medical device production.
{"title":"Analytical modelling of parallel multidirectional cutting of slender shafts","authors":"Wei Cai , Jingyang Xiang , Guojun Dong , Kee-hung Lai , Marian Wiercigroch","doi":"10.1016/j.ijmecsci.2025.110024","DOIUrl":"10.1016/j.ijmecsci.2025.110024","url":null,"abstract":"<div><div>Slender shafts have wide application on the aerospace, automotive and medical devices. However, they are prone to bending deformation during cutting process due to their low rigidity, resulting in poor machining accuracy and efficiency. A parallel multidirectional cutting (PMC) method is proposed using two tools to simultaneously cut the workpiece in forward or reverse directions contributing to overcome the problem of large deflections of these shafts. The main concept and PMC shared and unshared cutting modes are elucidated. An analytical model for PMC is established including chip geometry model, cutting force model and workpiece deflection feedback model. Given tool geometry, feed and depth of cut, chip load is accurately calculated using cutting edge discretization. The Johnson-Cook constitutive model is used to determine shear stress and shear force on the primary shear plane, and therefore the three-dimensional cutting force is obtained. The force condition of the workpiece is analysed under two clamping methods and the deformation of the workpiece is calculated and feed back into the model. On this basis, the influencing mechanism of cutting force, cutting power, cutting temperature and machining error of PMC is explored under different cutting modes, machined shaft geometry, tool parameters and cutting parameters. The smaller-the-better characteristic of Taguchi's method and signal-to-noise ratio are used to analyse the effect of cutting parameters on the PMC performance. Furthermore, an experimental validation is conducted to verify the cutting power, temperature, and diameter errors obtained by the proposed model, and the result shows a strong correlation with simulation predictions. The proposed method significantly improves machining precision and efficiency, with promising applications in high-precision manufacturing industries such as aerospace and medical device production.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"288 ","pages":"Article 110024"},"PeriodicalIF":7.1,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.ijmecsci.2025.109965
Gang Wang , Weilong Liu , Ziyuan Zhu , Yijie He , Menglong Dong , Jiajun Wu , Chuanyang Wang
Control of structural vibration and noise is crucial in the engineering field, and research on related technologies has significant engineering applications. This paper presents a semi-analytical analysis method to evaluate the vibro-acoustic properties of plate-cavity coupled systems with single or multiple symmetrically embedded suppressed acoustic spots (SAS). The numerical element division method (NEDM) combined with a power-law function to discretely approximate the SAS domain is used to solve the complex boundary integration problem. The spectral-geometry method (SGM) is adopted to express the plate displacement and the sound pressure in the cavity as continuous modified Fourier series to ensure boundary smoothness. Based on the Lagrange energy principle, the coupled theoretical model is constructed and the modal parameters are solved by the generalized Rayleigh-Ritz method, the accuracy of which is verified by comparison with the finite element method (FEM). The study discusses the vibro-acoustic attenuation mechanism of the SAS plate-cavity coupled system under the sound source excitation in the cavity, and the SAS plate parameters are analyzed in depth. The results reveal that when SAS with damping layers (SAS+DL) plates are used for noise reduction, an optimal match between SAS and damping layers needs to be sought rather than simply increasing SAS or damping, which provides a potential theoretical research basis for the design of damped structures applying the SAS principle.
{"title":"Vibro-acoustic behaviors of a plate-cavity symmetrically embedded with suppressed acoustic spots","authors":"Gang Wang , Weilong Liu , Ziyuan Zhu , Yijie He , Menglong Dong , Jiajun Wu , Chuanyang Wang","doi":"10.1016/j.ijmecsci.2025.109965","DOIUrl":"10.1016/j.ijmecsci.2025.109965","url":null,"abstract":"<div><div>Control of structural vibration and noise is crucial in the engineering field, and research on related technologies has significant engineering applications. This paper presents a semi-analytical analysis method to evaluate the vibro-acoustic properties of plate-cavity coupled systems with single or multiple symmetrically embedded suppressed acoustic spots (SAS). The numerical element division method (NEDM) combined with a power-law function to discretely approximate the SAS domain is used to solve the complex boundary integration problem. The spectral-geometry method (SGM) is adopted to express the plate displacement and the sound pressure in the cavity as continuous modified Fourier series to ensure boundary smoothness. Based on the Lagrange energy principle, the coupled theoretical model is constructed and the modal parameters are solved by the generalized Rayleigh-Ritz method, the accuracy of which is verified by comparison with the finite element method (FEM). The study discusses the vibro-acoustic attenuation mechanism of the SAS plate-cavity coupled system under the sound source excitation in the cavity, and the SAS plate parameters are analyzed in depth. The results reveal that when SAS with damping layers (SAS+DL) plates are used for noise reduction, an optimal match between SAS and damping layers needs to be sought rather than simply increasing SAS or damping, which provides a potential theoretical research basis for the design of damped structures applying the SAS principle.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"287 ","pages":"Article 109965"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-02-01DOI: 10.1016/j.ijmecsci.2025.109928
Liwei Dong , Chaoyang Zhao , Shuai Qu , Wei Ding , Guobiao Hu , Chengjia Han , Yaowen Yang
Galloping presents a significant challenge in engineering, often causing large-amplitude vibrations in structures such as suspended electrical cables, bridges and towers, posing substantial risks and property damage. While injecting high-frequency excitations can mitigate structural galloping, current active suppression methods, which apply excitations after galloping has developed, are suboptimal, limiting their widespread adoption. In this study, a low-cost and easy-to-implement passive galloping suppression approach utilizing flutter-induced vibrations is proposed, exhibiting robust anti-galloping effects under natural wind conditions. By strategically placing flags, high-frequency fluttering forces generated by wind flow are exploited to impose surface loads on the structure rapidly. This preemptively suppresses low-frequency galloping, mitigating its onset effectively without necessitating substantial force. A distributed aerodynamic model is developed to simulate the suppression phenomenon, accompanied by a comprehensive analysis considering factors such as flutter characteristics, wind speed, and flag position and geometric parameters. The analysis also explores distinct suppression mechanisms that arise when the fluttering frequency approaches the second and third modal frequencies of the structure. The proposed galloping suppression approach has been successfully simulated and validated through theoretical calculations and experimental tests, and test results showcase a significant reduction in vibration amplitudes, with suppression ratios ranging from 85% to 95% across wind speeds of 3 m/s to 10 m/s. Additionally, this approach demonstrates effective suppression capabilities under variable wind speed conditions, indicating its reliability and practicality for mitigating detrimental galloping in real-world scenarios.
{"title":"Structural galloping suppression with high-frequency flutter","authors":"Liwei Dong , Chaoyang Zhao , Shuai Qu , Wei Ding , Guobiao Hu , Chengjia Han , Yaowen Yang","doi":"10.1016/j.ijmecsci.2025.109928","DOIUrl":"10.1016/j.ijmecsci.2025.109928","url":null,"abstract":"<div><div>Galloping presents a significant challenge in engineering, often causing large-amplitude vibrations in structures such as suspended electrical cables, bridges and towers, posing substantial risks and property damage. While injecting high-frequency excitations can mitigate structural galloping, current active suppression methods, which apply excitations after galloping has developed, are suboptimal, limiting their widespread adoption. In this study, a low-cost and easy-to-implement passive galloping suppression approach utilizing flutter-induced vibrations is proposed, exhibiting robust anti-galloping effects under natural wind conditions. By strategically placing flags, high-frequency fluttering forces generated by wind flow are exploited to impose surface loads on the structure rapidly. This preemptively suppresses low-frequency galloping, mitigating its onset effectively without necessitating substantial force. A distributed aerodynamic model is developed to simulate the suppression phenomenon, accompanied by a comprehensive analysis considering factors such as flutter characteristics, wind speed, and flag position and geometric parameters. The analysis also explores distinct suppression mechanisms that arise when the fluttering frequency approaches the second and third modal frequencies of the structure. The proposed galloping suppression approach has been successfully simulated and validated through theoretical calculations and experimental tests, and test results showcase a significant reduction in vibration amplitudes, with suppression ratios ranging from 85% to 95% across wind speeds of 3 m/s to 10 m/s. Additionally, this approach demonstrates effective suppression capabilities under variable wind speed conditions, indicating its reliability and practicality for mitigating detrimental galloping in real-world scenarios.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"287 ","pages":"Article 109928"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143167443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-02-01DOI: 10.1016/j.ijmecsci.2025.109941
Liu Rong , Zhong Yifeng , Zhu Yilin , Cao Haiwen , Chen Minfang
The 3D orthogonal accordion core, formed by orthogonal combination of two 2D accordion honeycomb structure, exhibits a multi-directional zero Poisson’s ratio effect and exceptional deformation resistance. To effectively analyze the random-vibration characteristics of the sandwich panel with this type of core, a 2D equivalent Reissner–Mindlin model (2D-ERM) is developed using the variational asymptotic method. The precision of the 2D-ERM in free vibration analysis were validated using free modal vibration test of 3D printed specimens. Its precision in random vibration analysis was confirmed through comparison with 3D Finite Element (FE) simulations, including PSD/RMS responses. Modal analysis indicated that the relative error of 2D-ERM in predicting the first six eigenfrequencies remains below 2%, with the modal clouds demonstrating high reliability. Under base acceleration excitation, the displacement-PSD, velocity-PSD, and acceleration-PSD curves, along with RMS values obtained from 2D-ERM agree well with those from 3D-FEM for various boundary conditions, with the maximum error less than 5%. The length-to-thickness ratio of the extending strut significantly influences the equivalent stiffness, while the re-entrant angle and length-to-thickness ratio of the inclined strut exert the greatest impact on the eigenfrequency and displacement-PSD peak. Compared to SP-3D-XYAS, the equivalent density of SP-3D-OAC is reduced by up to 20%, while still achieving a low displacement-PSD peak. This balance, combined with the absence of coupling effects, makes SP-3D-OAC especially well-suited for applications in precision equipment supports and vibration isolation materials.
{"title":"Free and random-vibration characteristics of sandwich panels featuring orthogonal accordion cores","authors":"Liu Rong , Zhong Yifeng , Zhu Yilin , Cao Haiwen , Chen Minfang","doi":"10.1016/j.ijmecsci.2025.109941","DOIUrl":"10.1016/j.ijmecsci.2025.109941","url":null,"abstract":"<div><div>The 3D orthogonal accordion core, formed by orthogonal combination of two 2D accordion honeycomb structure, exhibits a multi-directional zero Poisson’s ratio effect and exceptional deformation resistance. To effectively analyze the random-vibration characteristics of the sandwich panel with this type of core, a 2D equivalent Reissner–Mindlin model (2D-ERM) is developed using the variational asymptotic method. The precision of the 2D-ERM in free vibration analysis were validated using free modal vibration test of 3D printed specimens. Its precision in random vibration analysis was confirmed through comparison with 3D Finite Element (FE) simulations, including PSD/RMS responses. Modal analysis indicated that the relative error of 2D-ERM in predicting the first six eigenfrequencies remains below 2%, with the modal clouds demonstrating high reliability. Under base acceleration excitation, the displacement-PSD, velocity-PSD, and acceleration-PSD curves, along with RMS values obtained from 2D-ERM agree well with those from 3D-FEM for various boundary conditions, with the maximum error less than 5%. The length-to-thickness ratio of the extending strut significantly influences the equivalent stiffness, while the re-entrant angle and length-to-thickness ratio of the inclined strut exert the greatest impact on the eigenfrequency and displacement-PSD peak. Compared to SP-3D-XYAS, the equivalent density of SP-3D-OAC is reduced by up to 20%, while still achieving a low displacement-PSD peak. This balance, combined with the absence of coupling effects, makes SP-3D-OAC especially well-suited for applications in precision equipment supports and vibration isolation materials.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"287 ","pages":"Article 109941"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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