Pub Date : 2024-12-25DOI: 10.1016/j.jsv.2024.118924
David E. Rosenstock, David Elata
We present a rigorous analysis of the in-plane flexural vibrations of a thin rotating circular ring. The ring is made from an anisotropic material with cubic symmetry, as in (100) single-crystalline silicon. The ring is assumed to be sufficiently thin, such that it can be considered as an inextensible Euler-Bernoulli beam. In this study, both the natural frequencies and their related mode shapes are analytically derived using an asymptotic method, for the modes numbered n = 2, 3 and 4. We show that due to a rate of rotation, these modes exhibit a precession-like response, which was previously shown to occur in isotropic rings. However, for rotating rings that are made from an anisotropic material, we show that the even-ordered modes n = 2 and n = 4, exhibit a ‘breathing’ phenomenon in the precessing mode. In deriving the asymptotic approximation of the frequencies and mode shapes, we adopt a technique used in quantum mechanics, and modify it appropriately for the problem at hand. The theoretical predictions are verified by comparing them to finite element simulations, showing good agreement. This work is relevant to the emerging technology of vibrating ring gyroscopes that are made from (100) single-crystalline silicon.
{"title":"Flexural vibrations of anisotropic thin rotating rings","authors":"David E. Rosenstock, David Elata","doi":"10.1016/j.jsv.2024.118924","DOIUrl":"10.1016/j.jsv.2024.118924","url":null,"abstract":"<div><div>We present a rigorous analysis of the in-plane flexural vibrations of a thin rotating circular ring. The ring is made from an anisotropic material with cubic symmetry, as in (100) single-crystalline silicon. The ring is assumed to be sufficiently thin, such that it can be considered as an inextensible Euler-Bernoulli beam. In this study, both the natural frequencies and their related mode shapes are analytically derived using an asymptotic method, for the modes numbered <em>n</em> = 2, 3 and 4. We show that due to a rate of rotation, these modes exhibit a precession-like response, which was previously shown to occur in isotropic rings. However, for rotating rings that are made from an anisotropic material, we show that the even-ordered modes <em>n</em> = 2 and <em>n</em> = 4, exhibit a ‘breathing’ phenomenon in the precessing mode. In deriving the asymptotic approximation of the frequencies and mode shapes, we adopt a technique used in quantum mechanics, and modify it appropriately for the problem at hand. The theoretical predictions are verified by comparing them to finite element simulations, showing good agreement. This work is relevant to the emerging technology of vibrating ring gyroscopes that are made from (100) single-crystalline silicon.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"604 ","pages":"Article 118924"},"PeriodicalIF":4.3,"publicationDate":"2024-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377747","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 : 2024-12-25DOI: 10.1016/j.jsv.2024.118923
Zhenwei Xu , Roshan S. Kaundinya , Shobhit Jain , George Haller
Dynamical systems in engineering and physics are often subject to irregular excitations that are best modeled as random. Monte Carlo simulations are routinely performed on such random models to obtain statistics on their long-term response. Such simulations, however, are prohibitively expensive and time consuming for high-dimensional nonlinear systems. Here we propose to decrease this numerical burden significantly by reducing the full system to very low-dimensional, attracting, random invariant manifolds in its phase space and performing the Monte Carlo simulations on that reduced dynamical system. The random spectral submanifolds (SSMs) we construct for this purpose generalize the concept of SSMs from deterministic systems under uniformly bounded random forcing. We illustrate the accuracy and speed of random SSM reduction by computing the SSM-reduced power spectral density of the randomly forced mechanical systems that range from simple oscillator chains to finite-element models of beams and plates.
{"title":"Nonlinear model reduction to random spectral submanifolds in random vibrations","authors":"Zhenwei Xu , Roshan S. Kaundinya , Shobhit Jain , George Haller","doi":"10.1016/j.jsv.2024.118923","DOIUrl":"10.1016/j.jsv.2024.118923","url":null,"abstract":"<div><div>Dynamical systems in engineering and physics are often subject to irregular excitations that are best modeled as random. Monte Carlo simulations are routinely performed on such random models to obtain statistics on their long-term response. Such simulations, however, are prohibitively expensive and time consuming for high-dimensional nonlinear systems. Here we propose to decrease this numerical burden significantly by reducing the full system to very low-dimensional, attracting, random invariant manifolds in its phase space and performing the Monte Carlo simulations on that reduced dynamical system. The random spectral submanifolds (SSMs) we construct for this purpose generalize the concept of SSMs from deterministic systems under uniformly bounded random forcing. We illustrate the accuracy and speed of random SSM reduction by computing the SSM-reduced power spectral density of the randomly forced mechanical systems that range from simple oscillator chains to finite-element models of beams and plates.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"600 ","pages":"Article 118923"},"PeriodicalIF":4.3,"publicationDate":"2024-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143175944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-12-24DOI: 10.1016/j.jsv.2024.118922
Chuan Wu, Guanchun Li, Dong Wang, Jie Xu
{"title":"Corrigendum to “Dynamic characterization of permanent magnet electrodynamic suspension system with a novel passive damping magnet scheme” [Journal of Sound and Vibration volume (2025) 118849]","authors":"Chuan Wu, Guanchun Li, Dong Wang, Jie Xu","doi":"10.1016/j.jsv.2024.118922","DOIUrl":"10.1016/j.jsv.2024.118922","url":null,"abstract":"","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"599 ","pages":"Article 118922"},"PeriodicalIF":4.3,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143152697","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 : 2024-12-21DOI: 10.1016/j.jsv.2024.118917
Tinnawat Hongphan , Ziv Brand , Matthew O.T. Cole
This study presents a novel approach for achieving model-free active vibration control of rotating cylindrical shells, addressing the challenges posed by incomplete knowledge of physical parameters and model structure. A technique exploiting rotational symmetry is introduced to reconstruct fixed-frame state variables from surface strain measurements, wherein the issue of sensor placement optimization is also addressed. An optimal control methodology based on adaptive dynamic programming (ADP) is then applied where feedback control solutions are computed directly from input-to-state observation data. To achieve prescribed damping levels for targeted flexural vibration modes, a data-based cost-function selection technique is also proposed. Numerical and experimental investigations involving a steel cylinder with fixed-frame electromagnetic actuator confirm the efficacy of the approach in achieving at least 15 % of critical damping, both with and without rotation. The results show significant promise for real-world vibration control problems, including application in machining operations on thin-walled cylinders.
{"title":"A model-free learning approach for active damping of a rotating cylindrical shell using ADP control with rotating-frame state reconstruction technique","authors":"Tinnawat Hongphan , Ziv Brand , Matthew O.T. Cole","doi":"10.1016/j.jsv.2024.118917","DOIUrl":"10.1016/j.jsv.2024.118917","url":null,"abstract":"<div><div>This study presents a novel approach for achieving model-free active vibration control of rotating cylindrical shells, addressing the challenges posed by incomplete knowledge of physical parameters and model structure. A technique exploiting rotational symmetry is introduced to reconstruct fixed-frame state variables from surface strain measurements, wherein the issue of sensor placement optimization is also addressed. An optimal control methodology based on adaptive dynamic programming (ADP) is then applied where feedback control solutions are computed directly from input-to-state observation data. To achieve prescribed damping levels for targeted flexural vibration modes, a data-based cost-function selection technique is also proposed. Numerical and experimental investigations involving a steel cylinder with fixed-frame electromagnetic actuator confirm the efficacy of the approach in achieving at least 15 % of critical damping, both with and without rotation. The results show significant promise for real-world vibration control problems, including application in machining operations on thin-walled cylinders.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"599 ","pages":"Article 118917"},"PeriodicalIF":4.3,"publicationDate":"2024-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143153376","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 : 2024-12-21DOI: 10.1016/j.jsv.2024.118920
Zhuyou Hu , He Guo , Zhihai Xiang
In recent years, the use of moving vehicles to reconstruct the mode shape of bridges has gained considerable interest due to its straightforward operational process. Despite its advantages, this technique is susceptible to the influence of road surface roughness and damping, and is also affected by time-frequency analysis techniques. Comprehensive strategies have been put forward to mitigate the effects of such interferences, including the application of excitations to enhance the signal-to-noise ratio, the employment of auxiliary stationary vehicles, and the reduction of damping through a priori techniques, among others. In order to explore an alternative economical solution, this study proposes to use the mode shape ratio to eliminate the impact of damping. This ratio is calculated in an innovative manner using the residual accelerations from a portable system that features with two auxiliary wheels oscillating at the same frequency as the moving vehicle. In this way, this technique simultaneously reduces the interference caused by the road surface roughness. The effectiveness of this proposed method has been demonstrated through a comprehensive set of numerical simulations across a wide range of parameter configurations. Particular emphasis has been placed on the time-frequency algorithms. The simulation results suggest that the Adaptive Superlet Transform method is a good choice to enhance the accuracy of modal position detection. Furthermore, numerical analyses are also conducted to explore the combined impact of detuned auxiliary wheels and edge effects.
{"title":"Bridge mode shape reconstruction through a moving vehicle with frequency-synchronized structures","authors":"Zhuyou Hu , He Guo , Zhihai Xiang","doi":"10.1016/j.jsv.2024.118920","DOIUrl":"10.1016/j.jsv.2024.118920","url":null,"abstract":"<div><div>In recent years, the use of moving vehicles to reconstruct the mode shape of bridges has gained considerable interest due to its straightforward operational process. Despite its advantages, this technique is susceptible to the influence of road surface roughness and damping, and is also affected by time-frequency analysis techniques. Comprehensive strategies have been put forward to mitigate the effects of such interferences, including the application of excitations to enhance the signal-to-noise ratio, the employment of auxiliary stationary vehicles, and the reduction of damping through a priori techniques, among others. In order to explore an alternative economical solution, this study proposes to use the mode shape ratio to eliminate the impact of damping. This ratio is calculated in an innovative manner using the residual accelerations from a portable system that features with two auxiliary wheels oscillating at the same frequency as the moving vehicle. In this way, this technique simultaneously reduces the interference caused by the road surface roughness. The effectiveness of this proposed method has been demonstrated through a comprehensive set of numerical simulations across a wide range of parameter configurations. Particular emphasis has been placed on the time-frequency algorithms. The simulation results suggest that the Adaptive Superlet Transform method is a good choice to enhance the accuracy of modal position detection. Furthermore, numerical analyses are also conducted to explore the combined impact of detuned auxiliary wheels and edge effects.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"599 ","pages":"Article 118920"},"PeriodicalIF":4.3,"publicationDate":"2024-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143152691","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 : 2024-12-20DOI: 10.1016/j.jsv.2024.118919
A. Stoffel , F. Margnat , C. Prax , F. Vanherpe
Whistling side-view mirror flows are investigated experimentally. Two designs are considered: the baseline, and a controlled one, whose cap is equipped with a protruding step, used as a vortex generator to turn the boundary layer turbulent upstream of the trailing edge. The acoustic field is measured with microphones while the inflow velocity is decreasing from 50 to 15 m s. Hot-wire anemometry and time-resolved particle image velocimetry are performed at 26 and 34 m s, synchronised with microphones, allowing whistling source localisation. Although the feedback loop that generates the tonal noise emission is deactivated in the controlled case in the step region, a switch from single tone to ladder-type structure tones is noticed on the outer side of this side-view mirror. This is associated with a flow intermittency in that region, at a low frequency corresponding to the peak distance. Fluctuation maps at the whistling frequencies are qualitatively different too, suggesting that, in the controlled case, the feedback loop is only active during the phase of the intermittent process when the shear layer deviates outward. This interpretation is supported by the estimation of a higher convection velocity of the fluctuations in the shear layer. Introducing the intermittency into time series models allows to reproduce the ladder-type structure, that is the harmonic jumps when the velocity increases. A Fourier analysis shows that whatever the vortex passing frequency over the trailing edge (e.g. as fixed by the feedback loop), the spectrum is made of harmonics of the intermittency frequency only. However, the specific velocities of rung changes on the ladder results from a higher growth rate of the passing frequency with velocity.
{"title":"Whistling side-view mirrors: Modelling ladder-type structure tonal noise from flow intermittency","authors":"A. Stoffel , F. Margnat , C. Prax , F. Vanherpe","doi":"10.1016/j.jsv.2024.118919","DOIUrl":"10.1016/j.jsv.2024.118919","url":null,"abstract":"<div><div>Whistling side-view mirror flows are investigated experimentally. Two designs are considered: the baseline, and a controlled one, whose cap is equipped with a protruding step, used as a vortex generator to turn the boundary layer turbulent upstream of the trailing edge. The acoustic field is measured with microphones while the inflow velocity is decreasing from 50 to 15 m s<span><math><msup><mrow></mrow><mrow><mi>−1</mi></mrow></msup></math></span>. Hot-wire anemometry and time-resolved particle image velocimetry are performed at 26 and 34 m s<span><math><msup><mrow></mrow><mrow><mi>−1</mi></mrow></msup></math></span>, synchronised with microphones, allowing whistling source localisation. Although the feedback loop that generates the tonal noise emission is deactivated in the controlled case in the step region, a switch from single tone to ladder-type structure tones is noticed on the outer side of this side-view mirror. This is associated with a flow intermittency in that region, at a low frequency corresponding to the peak distance. Fluctuation maps at the whistling frequencies are qualitatively different too, suggesting that, in the controlled case, the feedback loop is only active during the phase of the intermittent process when the shear layer deviates outward. This interpretation is supported by the estimation of a higher convection velocity of the fluctuations in the shear layer. Introducing the intermittency into time series models allows to reproduce the ladder-type structure, that is the harmonic jumps when the velocity increases. A Fourier analysis shows that whatever the vortex passing frequency over the trailing edge (e.g. as fixed by the feedback loop), the spectrum is made of harmonics of the intermittency frequency only. However, the specific velocities of rung changes on the ladder results from a higher growth rate of the passing frequency with velocity.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"601 ","pages":"Article 118919"},"PeriodicalIF":4.3,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143175518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-12-16DOI: 10.1016/j.jsv.2024.118908
Sahar Rosenberg, Oriel Shoshani
Nano- and micro-mechanical beams are widely used as resonators in research and engineering applications. One of the key challenges of utilizing their immense potential is effectively amplifying their signal above the noise floor level to achieve a large signal-to-noise ratio. In this study, building upon prior work, we develop an optimization procedure for the initial curvature of a mechanical beam that maximizes the inherent amplification of the forced transverse vibrations of the beam due to a nonlinear interaction with driven longitudinal vibrations. We focus on two possible cases: (i) direct amplification, which is obtained when the driving frequency of the longitudinal vibrations is close to the eigenfrequency of the transverse mode, and (ii) parametric amplification, which is obtained when the driving frequency of the longitudinal vibrations is close to twice the eigenfrequency of the transverse mode. By using a simple genetic algorithm scheme, we find that the optimal curved beams enhance the amplification by a factor of 205 for direct amplification and by a factor of 60 for parametric amplification.
{"title":"Shape optimization of a curved mechanical beam for transverse vibrations amplification via nonlinear interaction with longitudinal vibrations","authors":"Sahar Rosenberg, Oriel Shoshani","doi":"10.1016/j.jsv.2024.118908","DOIUrl":"10.1016/j.jsv.2024.118908","url":null,"abstract":"<div><div>Nano- and micro-mechanical beams are widely used as resonators in research and engineering applications. One of the key challenges of utilizing their immense potential is effectively amplifying their signal above the noise floor level to achieve a large signal-to-noise ratio. In this study, building upon prior work, we develop an optimization procedure for the initial curvature of a mechanical beam that maximizes the inherent amplification of the forced transverse vibrations of the beam due to a nonlinear interaction with driven longitudinal vibrations. We focus on two possible cases: (i) direct amplification, which is obtained when the driving frequency of the longitudinal vibrations is close to the eigenfrequency of the transverse mode, and (ii) parametric amplification, which is obtained when the driving frequency of the longitudinal vibrations is close to twice the eigenfrequency of the transverse mode. By using a simple genetic algorithm scheme, we find that the optimal curved beams enhance the amplification by a factor of 205 for direct amplification and by a factor of 60 for parametric amplification.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"599 ","pages":"Article 118908"},"PeriodicalIF":4.3,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143152693","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 : 2024-12-16DOI: 10.1016/j.jsv.2024.118918
Masoud Rezaei , Michael I Friswell , Wei-Hsin Liao
Mechanical oscillator resonance frequencies are of paramount importance and determine their performance from different perspectives such as bandwidth, vibration mitigation, and energy harvesting. As active tuning is hindered by energy consumption, this research investigates comprehensively for the first time if the inherent energy of a vibrating oscillator can supply the required energy to alter its natural frequency. To investigate the viability of this concept, a nonlinear partially covered piezoelectric beam-based oscillator with a full bridge rectifier and magnetic tuning mechanism under base excitation is considered, and its geometrically nonlinear model is derived. First, an approximate solution is proposed to study the capacitor charging process in steady-state excitation. Then, numerical integration and the multi- harmonic balance method (HBM) with pseudo-arclength continuation are exploited to investigate the nonlinear dynamics, mechanical response, and external capacitor voltage of the self-powered tunable oscillator (SPTOS). To investigate the sufficiency of the SPTOS energy for tuning, the required energy for different levels of change in the SPTOS natural frequency are obtained. It is found that the SPTOS can supply the energy to significantly change its natural frequency. The capacitor charging time and generated energy depend on the ratio of external capacitance to internal capacitance. The SPTOS efficiency under chirp excitation is then investigated, and the results show that both the chirp rate and the capacitance ratio affect the capacitor energy. Finally, by comparing the maxima of energy for the steady-state and chirp excitations, it is shown that the SPTOS energy in the former case is considerably higher than the latter case. Thus, the SPTOS can make larger changes in its frequency when excited in a steady-state scenario.
{"title":"Towards self-powered tunable mechanical oscillators: A conceptual study","authors":"Masoud Rezaei , Michael I Friswell , Wei-Hsin Liao","doi":"10.1016/j.jsv.2024.118918","DOIUrl":"10.1016/j.jsv.2024.118918","url":null,"abstract":"<div><div>Mechanical oscillator resonance frequencies are of paramount importance and determine their performance from different perspectives such as bandwidth, vibration mitigation, and energy harvesting. As active tuning is hindered by energy consumption, this research investigates comprehensively for the first time if the inherent energy of a vibrating oscillator can supply the required energy to alter its natural frequency. To investigate the viability of this concept, a nonlinear partially covered piezoelectric beam-based oscillator with a full bridge rectifier and magnetic tuning mechanism under base excitation is considered, and its geometrically nonlinear model is derived. First, an approximate solution is proposed to study the capacitor charging process in steady-state excitation. Then, numerical integration and the multi- harmonic balance method (HBM) with pseudo-arclength continuation are exploited to investigate the nonlinear dynamics, mechanical response, and external capacitor voltage of the self-powered tunable oscillator (SPTOS). To investigate the sufficiency of the SPTOS energy for tuning, the required energy for different levels of change in the SPTOS natural frequency are obtained. It is found that the SPTOS can supply the energy to significantly change its natural frequency. The capacitor charging time and generated energy depend on the ratio of external capacitance to internal capacitance. The SPTOS efficiency under chirp excitation is then investigated, and the results show that both the chirp rate and the capacitance ratio affect the capacitor energy. Finally, by comparing the maxima of energy for the steady-state and chirp excitations, it is shown that the SPTOS energy in the former case is considerably higher than the latter case. Thus, the SPTOS can make larger changes in its frequency when excited in a steady-state scenario.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"599 ","pages":"Article 118918"},"PeriodicalIF":4.3,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143152694","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 : 2024-12-16DOI: 10.1016/j.jsv.2024.118910
Weijia Li , Xiaohong Shen , Yaan Li , Zhe Chen , Jing Zhou
Detecting target signals in a reverberant underwater environment has long been a prominent and enduring challenge in the field of underwater acoustic signal processing. Traditional frequency-based methods are only effective when dealing with high signal-to-reverberation ratios (SRR) and significant Doppler shifts. This paper introduces the sample entropy (SampEn) and multiscale sample entropy (MSE) algorithms to explore the complexity differences between target echoes and reverberation. By conducting simulations under various SRR and Doppler shifts, we analyze the performance of traditional frequency-energy-based detection method, as well as entropy-based detection methods. The results show that in situations with a minor Doppler shift but a high SRR, frequency-based methods fail, yet the SampEn remains effective in detecting the target echo. Moreover, even when the Doppler shift is insignificant and SRR decreases to 0 dB, MSE can still detect the target echo.
{"title":"Detection of ship echo signals in reverberation background based on sample entropy and multiscale sample entropy","authors":"Weijia Li , Xiaohong Shen , Yaan Li , Zhe Chen , Jing Zhou","doi":"10.1016/j.jsv.2024.118910","DOIUrl":"10.1016/j.jsv.2024.118910","url":null,"abstract":"<div><div>Detecting target signals in a reverberant underwater environment has long been a prominent and enduring challenge in the field of underwater acoustic signal processing. Traditional frequency-based methods are only effective when dealing with high signal-to-reverberation ratios (SRR) and significant Doppler shifts. This paper introduces the sample entropy (SampEn) and multiscale sample entropy (MSE) algorithms to explore the complexity differences between target echoes and reverberation. By conducting simulations under various SRR and Doppler shifts, we analyze the performance of traditional frequency-energy-based detection method, as well as entropy-based detection methods. The results show that in situations with a minor Doppler shift but a high SRR, frequency-based methods fail, yet the SampEn remains effective in detecting the target echo. Moreover, even when the Doppler shift is insignificant and SRR decreases to 0 dB, MSE can still detect the target echo.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"599 ","pages":"Article 118910"},"PeriodicalIF":4.3,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143152696","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 : 2024-12-15DOI: 10.1016/j.jsv.2024.118872
Guimian Liu , Lili Zhang , Jiahao Liu , Hongguan Li , Guangshui Tong , Penghao Duan , Hanjun Jiang , Xia Kong , Fuhao Liu
Dynamic modeling of gear systems is typically constrained by the assumption of small vibration displacements. Additionally, the nonlinear effect of driving speed on evaluating the mesh stiffness with tooth root crack is neglected by many scholars. Based on this, a novel nonlinear dynamic model of a spur gear system that accurately accounts for large vibration displacements is established in this paper. Meanwhile, an original computational algorithm(OCA), based on analytical-FEM framework, is proposed to calculate the velocity-dependent time-varying mesh stiffness(V-TVMS) with tooth root crack, and whose accuracy is validated by FEM. The proposed dynamic model is compared with the traditional model under different support stiffness to illustrate its adaptability to large vibration displacements, and the influence of V-TVMS under different crack depths on the dynamic characteristics of the gear system is analyzed. The results analysis indicates that the fluctuation of V-TVMS intensifies with the increase of crack depth, which further exacerbates the nonlinear vibration of the gear system. And these phenomenons become more pronounced as crack depth increases. The reslut will provide valuable references for future studies on dynamics of cracked gears.
{"title":"Dynamics analysis for an improved gear model considering velocity-dependent mesh stiffness with tooth root crack","authors":"Guimian Liu , Lili Zhang , Jiahao Liu , Hongguan Li , Guangshui Tong , Penghao Duan , Hanjun Jiang , Xia Kong , Fuhao Liu","doi":"10.1016/j.jsv.2024.118872","DOIUrl":"10.1016/j.jsv.2024.118872","url":null,"abstract":"<div><div>Dynamic modeling of gear systems is typically constrained by the assumption of small vibration displacements. Additionally, the nonlinear effect of driving speed on evaluating the mesh stiffness with tooth root crack is neglected by many scholars. Based on this, a novel nonlinear dynamic model of a spur gear system that accurately accounts for large vibration displacements is established in this paper. Meanwhile, an original computational algorithm(OCA), based on analytical-FEM framework, is proposed to calculate the velocity-dependent time-varying mesh stiffness(V-TVMS) with tooth root crack, and whose accuracy is validated by FEM. The proposed dynamic model is compared with the traditional model under different support stiffness to illustrate its adaptability to large vibration displacements, and the influence of V-TVMS under different crack depths on the dynamic characteristics of the gear system is analyzed. The results analysis indicates that the fluctuation of V-TVMS intensifies with the increase of crack depth, which further exacerbates the nonlinear vibration of the gear system. And these phenomenons become more pronounced as crack depth increases. The reslut will provide valuable references for future studies on dynamics of cracked gears.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"600 ","pages":"Article 118872"},"PeriodicalIF":4.3,"publicationDate":"2024-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143175946","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