Pub Date : 2023-03-25DOI: 10.1177/14613484231166362
Yifeng Fu, Huming Wang, P. Cao
Underwater sound absorption materials with a stable performance at various hydrostatic pressures are important for marine applications. However, most studies about underwater sound absorption materials only focused on the performance at atmospheric hydrostatic pressure, while ignoring the influence of various hydrostatic pressures. Aiming to improve the underwater sound absorption stability of a metamaterial at various hydrostatic pressures, different structures and a Nelder–Mead algorithm with an acoustic-structure fully coupled finite element method (FEM) model are developed to optimize the structure of the metamaterial at various hydrostatic pressures. In this numerical modeling, the metamaterial is a PDMS matrix embedded with periodic cylinders. Firstly, the effect of hydrostatic pressure on the metamaterial is evaluated in the frequency range [0, 8 kHz]. Secondly, different cases are designed to improve the underwater sound absorption stability at various hydrostatic pressures, including different cylinder radii, different distances between the air cylinder and the steel backing, and different void shapes. Then two layers of air and/or steel cylinders are introduced to further improve sound absorption performance under various hydrostatic pressures. The results indicate that PDMS with two layers of air cylinders have the optimal sound absorption stability performance under various hydrostatic pressures, which can be attributed to the top layer of air cylinders absorbing the main deformation. Lastly, the optimization algorithm significantly improves the sound absorption performance of the metamaterials at various hydrostatic pressures. This combination of an optimistic algorithm and FEM can guide the design of underwater sound absorption metamaterials at various hydrostatic pressures.
{"title":"Numerical design and optimization of metamaterials for underwater sound absorption at various hydrostatic pressures","authors":"Yifeng Fu, Huming Wang, P. Cao","doi":"10.1177/14613484231166362","DOIUrl":"https://doi.org/10.1177/14613484231166362","url":null,"abstract":"Underwater sound absorption materials with a stable performance at various hydrostatic pressures are important for marine applications. However, most studies about underwater sound absorption materials only focused on the performance at atmospheric hydrostatic pressure, while ignoring the influence of various hydrostatic pressures. Aiming to improve the underwater sound absorption stability of a metamaterial at various hydrostatic pressures, different structures and a Nelder–Mead algorithm with an acoustic-structure fully coupled finite element method (FEM) model are developed to optimize the structure of the metamaterial at various hydrostatic pressures. In this numerical modeling, the metamaterial is a PDMS matrix embedded with periodic cylinders. Firstly, the effect of hydrostatic pressure on the metamaterial is evaluated in the frequency range [0, 8 kHz]. Secondly, different cases are designed to improve the underwater sound absorption stability at various hydrostatic pressures, including different cylinder radii, different distances between the air cylinder and the steel backing, and different void shapes. Then two layers of air and/or steel cylinders are introduced to further improve sound absorption performance under various hydrostatic pressures. The results indicate that PDMS with two layers of air cylinders have the optimal sound absorption stability performance under various hydrostatic pressures, which can be attributed to the top layer of air cylinders absorbing the main deformation. Lastly, the optimization algorithm significantly improves the sound absorption performance of the metamaterials at various hydrostatic pressures. This combination of an optimistic algorithm and FEM can guide the design of underwater sound absorption metamaterials at various hydrostatic pressures.","PeriodicalId":56067,"journal":{"name":"Journal of Low Frequency Noise Vibration and Active Control","volume":"84 1","pages":"1434 - 1450"},"PeriodicalIF":2.3,"publicationDate":"2023-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77042858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-03-15DOI: 10.1177/14613484231163997
Bowen Yao, Yanni Zhang, Qinbo Zhou, B. He, X. Rui
The acoustic black hole (ABH) has been proved to reduce broadband vibration response in beams and plates. While the traditional analytical and semi-analytical methods can only deal with the response of simple ABH structures; for complex ABH structures, the numerical methods such as the finite element method (FEM) have to be resorted and these methods are too often time-consuming. In this work, the vibration isolation by a beam structure embedded with periodic embedded symmetric ABHs is investigated. The vibration transmission of a single embedded symmetric ABH beam unit is first studied by the Riccati transfer matrix method (RTMM). A comparative analysis of the convergence speed and the computation efficiency of the unit by the RTMM and the FEM demonstrates the computation time using the RTMM increases linearly with the number of segments while that using the FEM increases exponentially and quickly exceeds the former as the number of segments increases. The computation time is consistent with the computational complexity associated with their respective algorithms. A hybrid dynamics method (HDM) is then proposed to derive for the vibration transmission solution of the beam with single and multiple periodically embedded symmetric ABHs. A comparison of the responses with those calculated by the RTMM demonstrates that the proposed HDM provides an efficient tool for solving the vibration response of the finite beam with periodic embedded ABHs, leading to much improved computational efficiency with ensured numerical stability and accuracy. This advantage in computation efficiency becomes even more obvious for larger structures when the number of the ABH units increased considerably. The proposed hybrid dynamic approach provides a basis for solving the vibration transmission/isolation problems of more complex ABH structures.
{"title":"Vibration isolation by a periodic beam with embedded acoustic black holes based on a hybrid dynamics method","authors":"Bowen Yao, Yanni Zhang, Qinbo Zhou, B. He, X. Rui","doi":"10.1177/14613484231163997","DOIUrl":"https://doi.org/10.1177/14613484231163997","url":null,"abstract":"The acoustic black hole (ABH) has been proved to reduce broadband vibration response in beams and plates. While the traditional analytical and semi-analytical methods can only deal with the response of simple ABH structures; for complex ABH structures, the numerical methods such as the finite element method (FEM) have to be resorted and these methods are too often time-consuming. In this work, the vibration isolation by a beam structure embedded with periodic embedded symmetric ABHs is investigated. The vibration transmission of a single embedded symmetric ABH beam unit is first studied by the Riccati transfer matrix method (RTMM). A comparative analysis of the convergence speed and the computation efficiency of the unit by the RTMM and the FEM demonstrates the computation time using the RTMM increases linearly with the number of segments while that using the FEM increases exponentially and quickly exceeds the former as the number of segments increases. The computation time is consistent with the computational complexity associated with their respective algorithms. A hybrid dynamics method (HDM) is then proposed to derive for the vibration transmission solution of the beam with single and multiple periodically embedded symmetric ABHs. A comparison of the responses with those calculated by the RTMM demonstrates that the proposed HDM provides an efficient tool for solving the vibration response of the finite beam with periodic embedded ABHs, leading to much improved computational efficiency with ensured numerical stability and accuracy. This advantage in computation efficiency becomes even more obvious for larger structures when the number of the ABH units increased considerably. The proposed hybrid dynamic approach provides a basis for solving the vibration transmission/isolation problems of more complex ABH structures.","PeriodicalId":56067,"journal":{"name":"Journal of Low Frequency Noise Vibration and Active Control","volume":"122 1","pages":"1419 - 1433"},"PeriodicalIF":2.3,"publicationDate":"2023-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90475500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-03-15DOI: 10.1177/14613484231162657
Guojuan Lv
The microelectromechanical devices have triggered rocketing interest in various advanced technologies, that is, sensors, material science, and energy harvesting, and now the devices tend to a nanoscale size, making the technology much more attractive in both academic and industrial communities. This paper takes a graphene nano/microelectromechanical system as an example to study its dynamical property, which is the foundation for the optimal design and reliable operation. As the system is inextricably complex with singularity and zero conditions in a fractal space, the iteration perturbation method is used to obtain the periodic solution of the system. The results show clearly the low-frequency property of the system and pull-in instability; furthermore, the fractal dimension affects greatly the system’s dynamical property.
{"title":"Dynamic behaviors for the graphene nano/microelectromechanical system in a fractal space","authors":"Guojuan Lv","doi":"10.1177/14613484231162657","DOIUrl":"https://doi.org/10.1177/14613484231162657","url":null,"abstract":"The microelectromechanical devices have triggered rocketing interest in various advanced technologies, that is, sensors, material science, and energy harvesting, and now the devices tend to a nanoscale size, making the technology much more attractive in both academic and industrial communities. This paper takes a graphene nano/microelectromechanical system as an example to study its dynamical property, which is the foundation for the optimal design and reliable operation. As the system is inextricably complex with singularity and zero conditions in a fractal space, the iteration perturbation method is used to obtain the periodic solution of the system. The results show clearly the low-frequency property of the system and pull-in instability; furthermore, the fractal dimension affects greatly the system’s dynamical property.","PeriodicalId":56067,"journal":{"name":"Journal of Low Frequency Noise Vibration and Active Control","volume":"14 1","pages":"1107 - 1116"},"PeriodicalIF":2.3,"publicationDate":"2023-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89369409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-03-14DOI: 10.1177/14613484231160151
J. Woodall, A. Maji, F. Moreu
This paper investigates the sensitivity of structural system response to the sensor location by investigating consequences of small changes in the location to the structural system response. The paper discusses how maximum observability (based on mode shape and the participation of that mode in the input provided) drives optimal location. The structural responses were investigated in terms of the g-rms response for various low-frequency inputs (pure sinusoids and real-life inputs such as an earthquake and trains). Results were then analyzed in the context of Modal Contributions Factors (MCF) and changes to the Force-to-response Transfer Functions (TRFs). A modal-matching process is first presented using a MatlabTM-based Finite Element Method (FEM) model of a cantilever beam and instrumentation to determine the location of a small mass based on three different criteria. Subsequently, the structural response is investigated using experiments and the FEM model. The accelerometer of small mass (at 1/3 height) was moved up or down to obtain changes in the structural response (TRF) to various realistic low-frequency inputs. Modal Contribution Factor (MCF) and derivative (slope) of the associated mode-shapes were correlated to the observed changes in TRFs. Results show how optimal sensor locations for detecting change in structural response can be based on the MCFs and the associated mode-shapes.
{"title":"Effective sensor location for detection of change in structural dynamic response","authors":"J. Woodall, A. Maji, F. Moreu","doi":"10.1177/14613484231160151","DOIUrl":"https://doi.org/10.1177/14613484231160151","url":null,"abstract":"This paper investigates the sensitivity of structural system response to the sensor location by investigating consequences of small changes in the location to the structural system response. The paper discusses how maximum observability (based on mode shape and the participation of that mode in the input provided) drives optimal location. The structural responses were investigated in terms of the g-rms response for various low-frequency inputs (pure sinusoids and real-life inputs such as an earthquake and trains). Results were then analyzed in the context of Modal Contributions Factors (MCF) and changes to the Force-to-response Transfer Functions (TRFs). A modal-matching process is first presented using a MatlabTM-based Finite Element Method (FEM) model of a cantilever beam and instrumentation to determine the location of a small mass based on three different criteria. Subsequently, the structural response is investigated using experiments and the FEM model. The accelerometer of small mass (at 1/3 height) was moved up or down to obtain changes in the structural response (TRF) to various realistic low-frequency inputs. Modal Contribution Factor (MCF) and derivative (slope) of the associated mode-shapes were correlated to the observed changes in TRFs. Results show how optimal sensor locations for detecting change in structural response can be based on the MCFs and the associated mode-shapes.","PeriodicalId":56067,"journal":{"name":"Journal of Low Frequency Noise Vibration and Active Control","volume":"26 1","pages":"1350 - 1362"},"PeriodicalIF":2.3,"publicationDate":"2023-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87254066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-03-14DOI: 10.1177/14613484231163947
N. Aljahdaly, Maram A. Alharbi, Abrar Alharbi, R. Alharbey, S. El-Tantawy
In this study, the nonlinear damping oscillations in a complex non-Maxwellian plasma are investigated. For this purpose, the set of fluid equations of the present plasma model is reduced to the Burger-modified Korteweg De Vries equation (BmKdV) equation using a reductive perturbation technique. Using the traveling wave transformation, the BmKdV equation can be reduced to a damped Duffing equation. The numerical solutions to the damped Duffing equation are obtained using multistage differential transformation method (MsDTM). Also, we compared the obtained results to the semi-analytical approximations using the Padé differential transformation (PDTM) method and numerical solution, by the 4th-order Rung Kutta (RK4) method and analytical solution by He’s frequency method. The impact of relevant plasma parameters, namely, negative dust concentrations and ion kinematic viscosity on the profile of dust ion-acoustic oscillations are examined. The suggested mathematical approaches can help many authors for explaining the mystery of their laboratory results. Moreover, the suggested numerical method can be applied for solving higher order nonlinearity oscillations for a long domain.
本文研究了复杂非麦克斯韦等离子体中的非线性阻尼振荡。为此，采用约化微扰技术将当前等离子体模型的流体方程组简化为Burger-modified Korteweg De Vries方程(BmKdV)。利用行波变换，可以将BmKdV方程简化为阻尼Duffing方程。采用多级微分变换方法，得到了阻尼Duffing方程的数值解。并将所得结果与pad微分变换(PDTM)法半解析近似和数值解、四阶Rung Kutta (RK4)法和He’s频率法解析解进行了比较。研究了相关等离子体参数，即负尘埃浓度和离子运动粘度对尘埃离子声振荡谱的影响。建议的数学方法可以帮助许多作者解释他们实验室结果的奥秘。此外，所提出的数值方法可用于求解长域的高阶非线性振荡。
{"title":"On the oscillations in a nonextensive complex plasma by improved differential transformation method: An application to a damped Duffing equation","authors":"N. Aljahdaly, Maram A. Alharbi, Abrar Alharbi, R. Alharbey, S. El-Tantawy","doi":"10.1177/14613484231163947","DOIUrl":"https://doi.org/10.1177/14613484231163947","url":null,"abstract":"In this study, the nonlinear damping oscillations in a complex non-Maxwellian plasma are investigated. For this purpose, the set of fluid equations of the present plasma model is reduced to the Burger-modified Korteweg De Vries equation (BmKdV) equation using a reductive perturbation technique. Using the traveling wave transformation, the BmKdV equation can be reduced to a damped Duffing equation. The numerical solutions to the damped Duffing equation are obtained using multistage differential transformation method (MsDTM). Also, we compared the obtained results to the semi-analytical approximations using the Padé differential transformation (PDTM) method and numerical solution, by the 4th-order Rung Kutta (RK4) method and analytical solution by He’s frequency method. The impact of relevant plasma parameters, namely, negative dust concentrations and ion kinematic viscosity on the profile of dust ion-acoustic oscillations are examined. The suggested mathematical approaches can help many authors for explaining the mystery of their laboratory results. Moreover, the suggested numerical method can be applied for solving higher order nonlinearity oscillations for a long domain.","PeriodicalId":56067,"journal":{"name":"Journal of Low Frequency Noise Vibration and Active Control","volume":"16 1","pages":"1319 - 1327"},"PeriodicalIF":2.3,"publicationDate":"2023-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85161618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The disc spring system is applied to the vibration screen, which can effectively reduce the exciting force and improve screening capacity. In this work, the dynamic characteristics and screening performance of the disc spring vibration screen are studied. The modal simulation and experimental results show that the model vibration direction at first natural frequency is consistent with the working direction of the vibration screen. Moreover, the trajectory analysis and discrete element screening simulation prove that the disc spring vibration screen has better screening performance than the coil spring vibration screen. Eventually, by comparing required exciting force under the same amplitude, fatigue life of the spindle bearing, and energy consumption between the coil spring and disc spring vibration screen, it can be found that disc spring vibration screen has better mechanical properties, higher reliability, and lower energy consumption.
{"title":"Study on the dynamics characteristics and screening performance of the disc spring vibration screen","authors":"Jiacheng Zhou, Libin Zhang, Longchao Cao, Junjie Tang, Kuanmin Mao, Lianqing Yu","doi":"10.1177/14613484231162455","DOIUrl":"https://doi.org/10.1177/14613484231162455","url":null,"abstract":"The disc spring system is applied to the vibration screen, which can effectively reduce the exciting force and improve screening capacity. In this work, the dynamic characteristics and screening performance of the disc spring vibration screen are studied. The modal simulation and experimental results show that the model vibration direction at first natural frequency is consistent with the working direction of the vibration screen. Moreover, the trajectory analysis and discrete element screening simulation prove that the disc spring vibration screen has better screening performance than the coil spring vibration screen. Eventually, by comparing required exciting force under the same amplitude, fatigue life of the spindle bearing, and energy consumption between the coil spring and disc spring vibration screen, it can be found that disc spring vibration screen has better mechanical properties, higher reliability, and lower energy consumption.","PeriodicalId":56067,"journal":{"name":"Journal of Low Frequency Noise Vibration and Active Control","volume":"31 1","pages":"1071 - 1086"},"PeriodicalIF":2.3,"publicationDate":"2023-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76616655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-03-10DOI: 10.1177/14613484231160150
Jing Wei, Miaofei Cao, Aiqiang Zhang, Hao Cheng, B. Peng
Considering the comprehensive effect of the internal non-inertial system of planetary gear transmission (PGT) and external non-inertial system of the body, combined with the modified Heywood formula and Hertz formula, a calculation model for the dynamic bending stress and contact dynamic stress of the PGT in a non-inertial system (NIS) is proposed. The stress non-inertial coefficients (KNI) describing the influence of the additional effects on the dynamic stress in the non-inertial system are defined. Additionally, the variation law of non-inertial coefficients under two typical non-inertial conditions of variable-speed horizontal flight and somersault motion was studied. The effect of gear installation and manufacturing errors on the non-inertial coefficients under two maneuvering conditions was analyzed. The results indicated that non-inertial coefficients increase with an increase in the maneuverability of the body, and the variable-speed horizontal flight and somersault motion have significant effects on the changing trend of non-inertial coefficients with the gear installation and manufacturing errors. Compared with the gear error, the effect of the NIS has a significant influence on the non-inertial coefficients.
{"title":"A study on dynamic stress of planetary gear transmission in non-inertial system","authors":"Jing Wei, Miaofei Cao, Aiqiang Zhang, Hao Cheng, B. Peng","doi":"10.1177/14613484231160150","DOIUrl":"https://doi.org/10.1177/14613484231160150","url":null,"abstract":"Considering the comprehensive effect of the internal non-inertial system of planetary gear transmission (PGT) and external non-inertial system of the body, combined with the modified Heywood formula and Hertz formula, a calculation model for the dynamic bending stress and contact dynamic stress of the PGT in a non-inertial system (NIS) is proposed. The stress non-inertial coefficients (KNI) describing the influence of the additional effects on the dynamic stress in the non-inertial system are defined. Additionally, the variation law of non-inertial coefficients under two typical non-inertial conditions of variable-speed horizontal flight and somersault motion was studied. The effect of gear installation and manufacturing errors on the non-inertial coefficients under two maneuvering conditions was analyzed. The results indicated that non-inertial coefficients increase with an increase in the maneuverability of the body, and the variable-speed horizontal flight and somersault motion have significant effects on the changing trend of non-inertial coefficients with the gear installation and manufacturing errors. Compared with the gear error, the effect of the NIS has a significant influence on the non-inertial coefficients.","PeriodicalId":56067,"journal":{"name":"Journal of Low Frequency Noise Vibration and Active Control","volume":"15 1","pages":"1087 - 1106"},"PeriodicalIF":2.3,"publicationDate":"2023-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72389772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-03-06DOI: 10.1177/14613484221149515
Yanni Zhang, Zhenyi Zhao, J. Pang
This paper deals with fractal Van der Pol damped nonlinear oscillators equation having nonlinearity. By combining the techniques of the Laplace transform and the variational iteration method, we establish approximate periodic solutions for the fractal damped nonlinear systems. In this simple way, nonlinear differential equations can be easily converted into linear differential equations. Illustrative examples including the Van der Pol damped nonlinear oscillator reveal that this method is very effective and convenient for solving fractal nonlinear differential equations. Finally, comparison of the obtained results with those of the other achieved method, also reveals that this coupling method not only suggests an easier method due to the Lagrange multiplier but also can be easily extended to other nonlinear systems.
{"title":"Approximate solutions of the fractional damped nonlinear oscillator subject to Van der Pol system","authors":"Yanni Zhang, Zhenyi Zhao, J. Pang","doi":"10.1177/14613484221149515","DOIUrl":"https://doi.org/10.1177/14613484221149515","url":null,"abstract":"This paper deals with fractal Van der Pol damped nonlinear oscillators equation having nonlinearity. By combining the techniques of the Laplace transform and the variational iteration method, we establish approximate periodic solutions for the fractal damped nonlinear systems. In this simple way, nonlinear differential equations can be easily converted into linear differential equations. Illustrative examples including the Van der Pol damped nonlinear oscillator reveal that this method is very effective and convenient for solving fractal nonlinear differential equations. Finally, comparison of the obtained results with those of the other achieved method, also reveals that this coupling method not only suggests an easier method due to the Lagrange multiplier but also can be easily extended to other nonlinear systems.","PeriodicalId":56067,"journal":{"name":"Journal of Low Frequency Noise Vibration and Active Control","volume":"31 1","pages":"1312 - 1318"},"PeriodicalIF":2.3,"publicationDate":"2023-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84646150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-03-03DOI: 10.1177/14613484231161425
Y. El‐Dib, Haifa A. Alyousef
In the present study, several successive approximate solutions of the nonlinear oscillator are derived by using the efficient frequency formula. A systematical analysis of the formulation of the nonlinear frequency helps to establish a general periodic solution. Each approximation represents, individually, the solution of the nonlinear oscillator. For the optimal design and accurate prediction of structural behavior, a new optimizer is demonstrated for efficient solutions. The classical Duffing frequency formula has been modified. The numerical calculations show high agreement with the exact frequency. The justifiability of the obtained solutions is confirmed by comparison with the numerical solution. It is shown that the enhanced solution is accurate for large amplitudes and is not restricted to oscillations that have small amplitudes. The new approach can provide a perfect approximation for the nonlinear oscillation.
{"title":"Successive approximate solutions for nonlinear oscillation and improvement of the solution accuracy with efficient non-perturbative technique","authors":"Y. El‐Dib, Haifa A. Alyousef","doi":"10.1177/14613484231161425","DOIUrl":"https://doi.org/10.1177/14613484231161425","url":null,"abstract":"In the present study, several successive approximate solutions of the nonlinear oscillator are derived by using the efficient frequency formula. A systematical analysis of the formulation of the nonlinear frequency helps to establish a general periodic solution. Each approximation represents, individually, the solution of the nonlinear oscillator. For the optimal design and accurate prediction of structural behavior, a new optimizer is demonstrated for efficient solutions. The classical Duffing frequency formula has been modified. The numerical calculations show high agreement with the exact frequency. The justifiability of the obtained solutions is confirmed by comparison with the numerical solution. It is shown that the enhanced solution is accurate for large amplitudes and is not restricted to oscillations that have small amplitudes. The new approach can provide a perfect approximation for the nonlinear oscillation.","PeriodicalId":56067,"journal":{"name":"Journal of Low Frequency Noise Vibration and Active Control","volume":"3 1","pages":"1296 - 1311"},"PeriodicalIF":2.3,"publicationDate":"2023-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89698774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-02-28DOI: 10.1177/14613484231160911
Pengchuang Liu, Yiqi Zhou, Rui Li
The unique dynamic characteristics and energy focalisation of the acoustic black hole (ABH) have been confirmed. Meanwhile, an ABH composite structure covered with a damping layer exhibits excellent performance in vibration control. However, limited by machining accuracy and conditions, imperfect ABH is easier to obtain than ideal ABH. This study focuses on the sound radiation characteristics of an imperfect ABH thin plate without a damping layer in the low-frequency range. The imperfect ABH in this paper replaces the traditional curve with an oblique line near the centre of two-dimensional ABH. The vibration and acoustic changes of imperfect ABH plate are investigated based on three key variables: ABH diameter, residual thickness and centre position of imperfect ABH indentation. The finite element method (FEM) is used to calculate the radiation efficiency of various imperfect ABH plates at eigenfrequencies. The acoustic radiation efficiency is measured and estimated via a sound-intensity experiment. Both the simulation and experimental results show that the acoustic radiation efficiency of thin plates can be controlled by an imperfect ABH in the low-frequency band, which is associated closely with the geometric parameters and position of imperfect ABH.
{"title":"Low-frequency sound radiation characteristics of imperfect acoustic black hole in thin plate","authors":"Pengchuang Liu, Yiqi Zhou, Rui Li","doi":"10.1177/14613484231160911","DOIUrl":"https://doi.org/10.1177/14613484231160911","url":null,"abstract":"The unique dynamic characteristics and energy focalisation of the acoustic black hole (ABH) have been confirmed. Meanwhile, an ABH composite structure covered with a damping layer exhibits excellent performance in vibration control. However, limited by machining accuracy and conditions, imperfect ABH is easier to obtain than ideal ABH. This study focuses on the sound radiation characteristics of an imperfect ABH thin plate without a damping layer in the low-frequency range. The imperfect ABH in this paper replaces the traditional curve with an oblique line near the centre of two-dimensional ABH. The vibration and acoustic changes of imperfect ABH plate are investigated based on three key variables: ABH diameter, residual thickness and centre position of imperfect ABH indentation. The finite element method (FEM) is used to calculate the radiation efficiency of various imperfect ABH plates at eigenfrequencies. The acoustic radiation efficiency is measured and estimated via a sound-intensity experiment. Both the simulation and experimental results show that the acoustic radiation efficiency of thin plates can be controlled by an imperfect ABH in the low-frequency band, which is associated closely with the geometric parameters and position of imperfect ABH.","PeriodicalId":56067,"journal":{"name":"Journal of Low Frequency Noise Vibration and Active Control","volume":"76 1","pages":"985 - 996"},"PeriodicalIF":2.3,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79619266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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