Pub Date : 2024-01-08DOI: 10.3390/vibration7010003
Yuli Zhao, M. Khayet, Xu Wang
A reliable prediction model can greatly contribute to the research of car seating system vibration control. The novelty of this paper lies in the development of a hybrid method of an artificial neural network (ANN) and response surface methodology (RSM) to predict the peak seat-to-head transmissibility ratio of a seating suspension system and to evaluate its ride comfort for different seat design parameters. Additionally, this method can remove the experimental design of the RSM model. In this paper, four seat design parameters are selected as input parameters and arranged using the central composite design method. The peak transmissibility ratio from seat to head at 4 Hz is chosen as the response target output value. To illustrate this hybrid method, the response target output value of the peak transmissibility ratio is calculated from the frequency response of a five-degrees-of-freedom (5-DOF) lumped-parameter biodynamic seating suspension model. The input design parameters and the response target output values are used to train an ANN to establish the relationship between the seat design parameters and the peak transmissibility ratio. At the same time, the input design parameters and the response target output values predicted by the ANN are used to develop the relationship between the seat design parameters and the peak transmissibility ratio using the response surface method and linear regression models. The hybrid of the ANN and response surface methods makes the planning or design of experiments not essential. The hybrid model of the ANN and response surface method is more accurate and convenient than a linear regression model for the study of seating system vibration isolation.
一个可靠的预测模型可以极大地促进汽车座椅系统振动控制的研究。本文的创新之处在于开发了一种人工神经网络（ANN）和响应面方法（RSM）的混合方法，用于预测座椅悬挂系统的峰值座面传递比，并评估不同座椅设计参数下的乘坐舒适性。此外，该方法还可以去除 RSM 模型的实验设计。本文选取四个座椅设计参数作为输入参数，并采用中心复合设计法进行排列。选择 4 Hz 时座椅到头部的峰值透射比作为响应目标输出值。为了说明这种混合方法，峰值传递率的响应目标输出值是通过五自由度（5-DOF）整数参数生物动力学座椅悬架模型的频率响应计算得出的。输入设计参数和响应目标输出值用于训练 ANN，以建立座椅设计参数与峰值传递率之间的关系。同时，使用响应面法和线性回归模型，将输入设计参数和 ANN 预测的响应目标输出值用于建立座椅设计参数与峰值传递率之间的关系。由于采用了方差网络和响应面法的混合方法，因此不需要进行试验规划或设计。在座椅系统隔振研究中，ANN 和响应面法的混合模型比线性回归模型更准确、更方便。
{"title":"A Study of Seating Suspension System Vibration Isolation Using a Hybrid Method of an Artificial Neural Network and Response Surface Modelling","authors":"Yuli Zhao, M. Khayet, Xu Wang","doi":"10.3390/vibration7010003","DOIUrl":"https://doi.org/10.3390/vibration7010003","url":null,"abstract":"A reliable prediction model can greatly contribute to the research of car seating system vibration control. The novelty of this paper lies in the development of a hybrid method of an artificial neural network (ANN) and response surface methodology (RSM) to predict the peak seat-to-head transmissibility ratio of a seating suspension system and to evaluate its ride comfort for different seat design parameters. Additionally, this method can remove the experimental design of the RSM model. In this paper, four seat design parameters are selected as input parameters and arranged using the central composite design method. The peak transmissibility ratio from seat to head at 4 Hz is chosen as the response target output value. To illustrate this hybrid method, the response target output value of the peak transmissibility ratio is calculated from the frequency response of a five-degrees-of-freedom (5-DOF) lumped-parameter biodynamic seating suspension model. The input design parameters and the response target output values are used to train an ANN to establish the relationship between the seat design parameters and the peak transmissibility ratio. At the same time, the input design parameters and the response target output values predicted by the ANN are used to develop the relationship between the seat design parameters and the peak transmissibility ratio using the response surface method and linear regression models. The hybrid of the ANN and response surface methods makes the planning or design of experiments not essential. The hybrid model of the ANN and response surface method is more accurate and convenient than a linear regression model for the study of seating system vibration isolation.","PeriodicalId":75301,"journal":{"name":"Vibration","volume":"4 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139447004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The contact-less sensing and fault diagnosis characteristics induced by fixing short Metglas® 2826MB ribbons onto the surface of thin cantilever polymer beams are examined and statistically evaluated in this study. Excitation of the beam’s free end generates magnetic flux from the vibrating ribbon (fixed near the clamp side), which, via a coil suspended above the ribbon surface, is recorded as voltage with an oscilloscope. Cost-efficient design and operation are key objectives of this setup since only conventional equipment (coil, oscilloscope) is used, whereas filtering, amplification and similar circuits are absent. A statistical framework for extending past findings on the relationship between spectral changes in voltage and fault occurrence is introduced. Currently, different levels of beam excitation (within a frequency range) are shown to result in statistically different voltage spectral changes (frequency shifts). The principle is also valid for loads (faults) of different magnitudes and/or locations on the beam for a given excitation. Testing with either various beam excitation frequencies or different loads (magnitude/locations) at a given excitation demonstrates that voltage spectral changes are statistically mapped onto excitation levels or occurrences of distinct faults (loads). Thus, conventional beams may cost-efficiently acquire contact-less sensing and fault diagnosis capabilities using limited hardware/equipment.
{"title":"Evaluating Contact-Less Sensing and Fault Diagnosis Characteristics in Vibrating Thin Cantilever Beams with a MetGlas® 2826MB Ribbon","authors":"Robert-Gabriel Sultana, Achilleas Davrados, Dimitrios Dimogianopoulos","doi":"10.3390/vibration7010002","DOIUrl":"https://doi.org/10.3390/vibration7010002","url":null,"abstract":"The contact-less sensing and fault diagnosis characteristics induced by fixing short Metglas® 2826MB ribbons onto the surface of thin cantilever polymer beams are examined and statistically evaluated in this study. Excitation of the beam’s free end generates magnetic flux from the vibrating ribbon (fixed near the clamp side), which, via a coil suspended above the ribbon surface, is recorded as voltage with an oscilloscope. Cost-efficient design and operation are key objectives of this setup since only conventional equipment (coil, oscilloscope) is used, whereas filtering, amplification and similar circuits are absent. A statistical framework for extending past findings on the relationship between spectral changes in voltage and fault occurrence is introduced. Currently, different levels of beam excitation (within a frequency range) are shown to result in statistically different voltage spectral changes (frequency shifts). The principle is also valid for loads (faults) of different magnitudes and/or locations on the beam for a given excitation. Testing with either various beam excitation frequencies or different loads (magnitude/locations) at a given excitation demonstrates that voltage spectral changes are statistically mapped onto excitation levels or occurrences of distinct faults (loads). Thus, conventional beams may cost-efficiently acquire contact-less sensing and fault diagnosis capabilities using limited hardware/equipment.","PeriodicalId":75301,"journal":{"name":"Vibration","volume":"56 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139449525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-21DOI: 10.3390/vibration7010001
Bernhard Heinemann, Kai Simanowski, Michael Clasen, Jan Dreesen, D. Sachau
Shockmounts in naval applications are used to mount technical equipment onto the structure of naval vessels. The insulating effect against mechanical shock is important here, as it can excite the structure in the event of underwater explosions and otherwise cause damage to the equipment. Although knowledge of the dynamic properties of shockmounts is important to naval architects, the dynamic force-displacement characteristics of shockmounts are often tested and measured statically and/or in the harmonic field. Recently, an inertia-based method and a dynamic model for measuring the dynamic force-displacement characteristics of shockmounts was described. This paper presents a full description of a testbench for implementing this method. The testbench incorporates a drop table for excitation. The proposed setup can be configured for measuring the dynamic characteristics of elastomer and wire rope shockmounts, with shock loads in compression, tension, shear and roll directions. The advanced Kelvin–Voigt model for shockmounts is applied, showing that the dynamic force-displacement characteristics measured with this setup are qualified to generate model parameters for further use.
{"title":"A Testbench for Measuring the Dynamic Force-Displacement Characteristics of Shockmounts","authors":"Bernhard Heinemann, Kai Simanowski, Michael Clasen, Jan Dreesen, D. Sachau","doi":"10.3390/vibration7010001","DOIUrl":"https://doi.org/10.3390/vibration7010001","url":null,"abstract":"Shockmounts in naval applications are used to mount technical equipment onto the structure of naval vessels. The insulating effect against mechanical shock is important here, as it can excite the structure in the event of underwater explosions and otherwise cause damage to the equipment. Although knowledge of the dynamic properties of shockmounts is important to naval architects, the dynamic force-displacement characteristics of shockmounts are often tested and measured statically and/or in the harmonic field. Recently, an inertia-based method and a dynamic model for measuring the dynamic force-displacement characteristics of shockmounts was described. This paper presents a full description of a testbench for implementing this method. The testbench incorporates a drop table for excitation. The proposed setup can be configured for measuring the dynamic characteristics of elastomer and wire rope shockmounts, with shock loads in compression, tension, shear and roll directions. The advanced Kelvin–Voigt model for shockmounts is applied, showing that the dynamic force-displacement characteristics measured with this setup are qualified to generate model parameters for further use.","PeriodicalId":75301,"journal":{"name":"Vibration","volume":"44 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138948840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-12DOI: 10.3390/vibration6040062
Yuanjing Wang, Pengxuan Lei, Binbin Lv, Yuchen Li, H. Guo
The influence of trailing edge deformation on the aerodynamic characteristics of camber morphing wings is an important topic in the aviation field. In this paper, a new memory alloy actuator is proposed to realize trailing edge deformation, and computational fluid dynamics (CFD) and wind tunnel experiments are used to study the influence of trailing edge deformation on the aerodynamic characteristics of the camber morphing wings. The experiments was carried out in a transonic wind tunnel with Mach numbers ranging from 0.4 to 0.8 and angles of attack ranging from 0° to 6°. The external flow fields and aerodynamic force coefficients with and without deformation were calculated using the CFD method. A loose coupled method based on data exchange was used to achieve a fluid–structure interaction (FSI) analysis. The research results indicate that when the trailing edge is deflected downwards, the phenomenon of shock wave forward movement reduces the negative pressure area on the upper wing surface, increases the pressure on the lower wing surface, and ultimately increases the total lift. This work provides a new approach for the implementation of trailing edge deformation and a powerful data reference for the design of camber morphing wings.
{"title":"Study on Fluid–Structure Interaction of a Camber Morphing Wing","authors":"Yuanjing Wang, Pengxuan Lei, Binbin Lv, Yuchen Li, H. Guo","doi":"10.3390/vibration6040062","DOIUrl":"https://doi.org/10.3390/vibration6040062","url":null,"abstract":"The influence of trailing edge deformation on the aerodynamic characteristics of camber morphing wings is an important topic in the aviation field. In this paper, a new memory alloy actuator is proposed to realize trailing edge deformation, and computational fluid dynamics (CFD) and wind tunnel experiments are used to study the influence of trailing edge deformation on the aerodynamic characteristics of the camber morphing wings. The experiments was carried out in a transonic wind tunnel with Mach numbers ranging from 0.4 to 0.8 and angles of attack ranging from 0° to 6°. The external flow fields and aerodynamic force coefficients with and without deformation were calculated using the CFD method. A loose coupled method based on data exchange was used to achieve a fluid–structure interaction (FSI) analysis. The research results indicate that when the trailing edge is deflected downwards, the phenomenon of shock wave forward movement reduces the negative pressure area on the upper wing surface, increases the pressure on the lower wing surface, and ultimately increases the total lift. This work provides a new approach for the implementation of trailing edge deformation and a powerful data reference for the design of camber morphing wings.","PeriodicalId":75301,"journal":{"name":"Vibration","volume":"4 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139008754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-08DOI: 10.3390/vibration6040061
Tian Li, Yifan Li, Lai Wei, Ji-ye Zhang
As the speed of high-speed trains increases, the vehicle’s lateral stability steadily deteriorates. There have been observations of abnormal vibrations in the tail car, particularly on certain sections of the railway line. This study built a high-speed train aerodynamic simulation model for a three-car consist, and a multibody dynamics simulation model for an eight-car consist based on numerical simulations of train aerodynamics and multibody dynamics. It investigated both steady and unsteady aerodynamic loads, flow field characteristics, and the dynamic performance of vehicles under varied aerodynamic loads at 400 km/h. The results indicate that the aerodynamic loads generated during high-speed train operation exhibit highly unsteady characteristics. Steady aerodynamic loads have a relatively minor impact on the vehicle’s dynamic performance, whereas unsteady loads exert a more significant influence. Under unsteady aerodynamic forces, the tail car experiences severe lateral vibrations. The lateral stability index, displacement, velocity, and acceleration of the tail car under unsteady conditions were measured at 2.26, 7.54 mm, and 0.53 m/s2, respectively. These values represent increases of over 17.71%, 148.84%, and 111.24%, respectively, compared to the steady loads. Large oscillation amplitudes result in more significant lateral displacements and accelerations of the vehicle. This phenomenon is a crucial factor contributing to the “tail swing” effect observed in high-speed trains. This study emphasizes the importance of considering unsteady aerodynamic effects in assessing the lateral stability of high-speed trains and highlights the significance of mitigating the adverse impacts of such dynamic responses, particularly in the tail car.
{"title":"Study on Lateral Vibration of Tail Coach for High-Speed Train under Unsteady Aerodynamic Loads","authors":"Tian Li, Yifan Li, Lai Wei, Ji-ye Zhang","doi":"10.3390/vibration6040061","DOIUrl":"https://doi.org/10.3390/vibration6040061","url":null,"abstract":"As the speed of high-speed trains increases, the vehicle’s lateral stability steadily deteriorates. There have been observations of abnormal vibrations in the tail car, particularly on certain sections of the railway line. This study built a high-speed train aerodynamic simulation model for a three-car consist, and a multibody dynamics simulation model for an eight-car consist based on numerical simulations of train aerodynamics and multibody dynamics. It investigated both steady and unsteady aerodynamic loads, flow field characteristics, and the dynamic performance of vehicles under varied aerodynamic loads at 400 km/h. The results indicate that the aerodynamic loads generated during high-speed train operation exhibit highly unsteady characteristics. Steady aerodynamic loads have a relatively minor impact on the vehicle’s dynamic performance, whereas unsteady loads exert a more significant influence. Under unsteady aerodynamic forces, the tail car experiences severe lateral vibrations. The lateral stability index, displacement, velocity, and acceleration of the tail car under unsteady conditions were measured at 2.26, 7.54 mm, and 0.53 m/s2, respectively. These values represent increases of over 17.71%, 148.84%, and 111.24%, respectively, compared to the steady loads. Large oscillation amplitudes result in more significant lateral displacements and accelerations of the vehicle. This phenomenon is a crucial factor contributing to the “tail swing” effect observed in high-speed trains. This study emphasizes the importance of considering unsteady aerodynamic effects in assessing the lateral stability of high-speed trains and highlights the significance of mitigating the adverse impacts of such dynamic responses, particularly in the tail car.","PeriodicalId":75301,"journal":{"name":"Vibration","volume":"33 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138587665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Efficient maintenance in the face of complex and interconnected industrial equipment is crucial for corporate competitiveness. Traditional reactive approaches often prove inadequate, necessitating a shift towards proactive strategies. This study addresses the challenges of data scarcity and timely defect identification by providing practical guidance for selecting optimal solutions for various equipment malfunction scenarios. Utilizing three datasets—Machine Sound to Machine Condition Monitoring and Intelligent Information (MIMII), Case Western Reserve University (CWRU), and Machinery Failure Prevention Technology (MFPT)—the study employs the Short-Time Fourier Transform (STFT) as a preprocessing method to enhance feature extraction. To determine the best preprocessing technique, Gammatone Transformation, and raw data are also considered. The research optimizes performance and training efficiency by adjusting hyperparameters, minimizing overfitting, and using the KERAS Early Halting API within resource constraints. To address data scarcity, which is one of the major obstacles to detecting faults in the industrial environment, Few-shot learning (FSL) is employed. Various architectures, including ConvNeXt Base, Large MobileNetV3, ResNet-18, and ResNet-50, are incorporated within a prototypical network-based few-shot learning model. MobileNet’s lower parameter count, high accuracy, efficiency, and portability make it the ideal choice for this application. By combining few-shot learning, MobileNet architecture, and STFT preprocessing, this study proposes a practical and data-efficient fault diagnosis method. The model demonstrates adaptability across datasets, offering valuable insights for enhancing industrial fault detection and preventive maintenance procedures.
{"title":"A Few-Shot Learning Based Fault Diagnosis Model Using Sensors Data from Industrial Machineries","authors":"Farhan Md. Siraj, Syed Tasnimul Karim Ayon, Jia Uddin","doi":"10.3390/vibration6040059","DOIUrl":"https://doi.org/10.3390/vibration6040059","url":null,"abstract":"Efficient maintenance in the face of complex and interconnected industrial equipment is crucial for corporate competitiveness. Traditional reactive approaches often prove inadequate, necessitating a shift towards proactive strategies. This study addresses the challenges of data scarcity and timely defect identification by providing practical guidance for selecting optimal solutions for various equipment malfunction scenarios. Utilizing three datasets—Machine Sound to Machine Condition Monitoring and Intelligent Information (MIMII), Case Western Reserve University (CWRU), and Machinery Failure Prevention Technology (MFPT)—the study employs the Short-Time Fourier Transform (STFT) as a preprocessing method to enhance feature extraction. To determine the best preprocessing technique, Gammatone Transformation, and raw data are also considered. The research optimizes performance and training efficiency by adjusting hyperparameters, minimizing overfitting, and using the KERAS Early Halting API within resource constraints. To address data scarcity, which is one of the major obstacles to detecting faults in the industrial environment, Few-shot learning (FSL) is employed. Various architectures, including ConvNeXt Base, Large MobileNetV3, ResNet-18, and ResNet-50, are incorporated within a prototypical network-based few-shot learning model. MobileNet’s lower parameter count, high accuracy, efficiency, and portability make it the ideal choice for this application. By combining few-shot learning, MobileNet architecture, and STFT preprocessing, this study proposes a practical and data-efficient fault diagnosis method. The model demonstrates adaptability across datasets, offering valuable insights for enhancing industrial fault detection and preventive maintenance procedures.","PeriodicalId":75301,"journal":{"name":"Vibration","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134902644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To simulate a lightweight structure with integrated actuators and sensors, two-dimensional finite elements are utilized. The study looks at the optimal location and active vibration control for a piezoelectric smart flexible structure. Intelligent applications are commonly used in engineering applications. In computational mechanics, selecting the ideal position for actuators to suppress oscillations is crucial. The structure oscillates due to dynamic disturbance, and active control is used to try to reduce the oscillation. Utilizing an LQR and Hinfinity controller, optimization is carried out to determine the best controller weights, which will dampen the oscillation. Challenging issues arise in the design of control techniques for piezoelectric smart structures. Piezoelectric materials have been investigated for use in distributed parameter systems (for example airplane wings, intelligent bridges, etc.) to provide active control efficiently and affordably. Still, no full suppression of the oscillation with this approach has been achieved so far. The controller’s order is then decreased using optimization techniques. Piezoelectric actuators are positioned optimally according to an enhanced optimization method. The outcomes demonstrate that the actuator optimization strategies used in the piezoelectric smart single flexible manipulator system have increased observability in addition to good vibration suppression results.
{"title":"Optimal Placement and Active Control Methods for Integrating Smart Material in Dynamic Suppression Structures","authors":"Amalia Moutsopoulou, Georgios E. Stavroulakis, Markos Petousis, Anastasios Pouliezos, Nectarios Vidakis","doi":"10.3390/vibration6040058","DOIUrl":"https://doi.org/10.3390/vibration6040058","url":null,"abstract":"To simulate a lightweight structure with integrated actuators and sensors, two-dimensional finite elements are utilized. The study looks at the optimal location and active vibration control for a piezoelectric smart flexible structure. Intelligent applications are commonly used in engineering applications. In computational mechanics, selecting the ideal position for actuators to suppress oscillations is crucial. The structure oscillates due to dynamic disturbance, and active control is used to try to reduce the oscillation. Utilizing an LQR and Hinfinity controller, optimization is carried out to determine the best controller weights, which will dampen the oscillation. Challenging issues arise in the design of control techniques for piezoelectric smart structures. Piezoelectric materials have been investigated for use in distributed parameter systems (for example airplane wings, intelligent bridges, etc.) to provide active control efficiently and affordably. Still, no full suppression of the oscillation with this approach has been achieved so far. The controller’s order is then decreased using optimization techniques. Piezoelectric actuators are positioned optimally according to an enhanced optimization method. The outcomes demonstrate that the actuator optimization strategies used in the piezoelectric smart single flexible manipulator system have increased observability in addition to good vibration suppression results.","PeriodicalId":75301,"journal":{"name":"Vibration","volume":"361 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135392038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-04DOI: 10.3390/vibration6040057
Nurlan Zhangabay, Marco Bonopera, Akmaral Utelbayeva, Timur Tursunkululy, Murat Rakhimov
This article analyzes the convergence of the obtained values as a result of the authors’ earlier experimental and theoretical studies. On the basis of the correlations, it was found that the analyses of a traditional cylindrical steel tank without a steel wire strand wrapping and with a filling level of zero by a liquid showed a difference in natural vibration frequencies of 8.4%, while with half and maximal filling by a liquid showed differences equal to 3.2% and 6.2%, respectively. Vice versa, analyses of a cylindrical steel tank with a steel wire strand winding pitch of a = 3d and with a filling level of zero by a liquid showed a difference in natural vibration frequencies of 8.1%, while with half and maximum filling by a liquid and with the same steel wire strand winding pitch showed differences of 10.1% and 5.9%, respectively. Conversely, analyses of a cylindrical steel tank with a steel wire strand winding pitch of a = d and in absence of filling level amounted to a difference of 5.5%, while with half and maximum filling and with the same steel wire strand winding pitch of a = d, differences of 1.6% and 1.4% were, respectively, achieved. Based on the aforementioned results, the general difference between experimental and theoretical vibration frequencies showed up to 10%, which is a satisfactory result of convergence. The obtained findings of this research can be used by engineers and technical workers in the industries of various fields, research institutes and professional companies in designing new earthquake-resistant steel tanks and strengthening existing ones. Conclusions were then mentioned at the end of the article.
{"title":"Experimental and Theoretical Reproducibility Research on the Earthquake Resistance of Cylindrical Steel Tanks","authors":"Nurlan Zhangabay, Marco Bonopera, Akmaral Utelbayeva, Timur Tursunkululy, Murat Rakhimov","doi":"10.3390/vibration6040057","DOIUrl":"https://doi.org/10.3390/vibration6040057","url":null,"abstract":"This article analyzes the convergence of the obtained values as a result of the authors’ earlier experimental and theoretical studies. On the basis of the correlations, it was found that the analyses of a traditional cylindrical steel tank without a steel wire strand wrapping and with a filling level of zero by a liquid showed a difference in natural vibration frequencies of 8.4%, while with half and maximal filling by a liquid showed differences equal to 3.2% and 6.2%, respectively. Vice versa, analyses of a cylindrical steel tank with a steel wire strand winding pitch of a = 3d and with a filling level of zero by a liquid showed a difference in natural vibration frequencies of 8.1%, while with half and maximum filling by a liquid and with the same steel wire strand winding pitch showed differences of 10.1% and 5.9%, respectively. Conversely, analyses of a cylindrical steel tank with a steel wire strand winding pitch of a = d and in absence of filling level amounted to a difference of 5.5%, while with half and maximum filling and with the same steel wire strand winding pitch of a = d, differences of 1.6% and 1.4% were, respectively, achieved. Based on the aforementioned results, the general difference between experimental and theoretical vibration frequencies showed up to 10%, which is a satisfactory result of convergence. The obtained findings of this research can be used by engineers and technical workers in the industries of various fields, research institutes and professional companies in designing new earthquake-resistant steel tanks and strengthening existing ones. Conclusions were then mentioned at the end of the article.","PeriodicalId":75301,"journal":{"name":"Vibration","volume":"39 17","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135773646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-18DOI: 10.3390/vibration6040055
Andrea Dincher
Parkinson’s disease is an incurable neurological disease. Only the symptoms can be treated with medication or exercise therapy. The present analysis is intended to show how whole-body vibration training affects the symptoms of Parkinson’s disease, distinguishing between acute and long-term effects. Methods: online databases (EMBASE, PubMed, PEDro) were searched for reviews, meta-analyses and new studies since the previous most recent review/meta-analysis. Studies with at least a medium methodological quality (PEDro score at least 5 points) were selected. Results were presented as forest plots that indicated standardized mean differences with 95% confidence interval. Results: Sixteen studies were found with a PEDro-score of at least 5 points. Of these, three studies were excluded from the qualitative analysis because the necessary data, such as standard deviation or control group results, were missing. The effect sizes are very mixed. In some parameters there is no effect, in others a very strong effect. The effects in the comparison between single and multiple treatments are similar. Discussion: The different effects may be partly due to the different vibration frequencies or sentence durations, as well as to different valid test procedures. Conclusions: Since the study situation still does not show clear results, further studies must follow that compare different frequencies, sentence durations and vibration types with each other, so that training recommendations can be given on this basis.
{"title":"Effects of a Single Session of Whole Body Vibration Compared to Multiple Sessions—An Updated Review and Meta-Analysis","authors":"Andrea Dincher","doi":"10.3390/vibration6040055","DOIUrl":"https://doi.org/10.3390/vibration6040055","url":null,"abstract":"Parkinson’s disease is an incurable neurological disease. Only the symptoms can be treated with medication or exercise therapy. The present analysis is intended to show how whole-body vibration training affects the symptoms of Parkinson’s disease, distinguishing between acute and long-term effects. Methods: online databases (EMBASE, PubMed, PEDro) were searched for reviews, meta-analyses and new studies since the previous most recent review/meta-analysis. Studies with at least a medium methodological quality (PEDro score at least 5 points) were selected. Results were presented as forest plots that indicated standardized mean differences with 95% confidence interval. Results: Sixteen studies were found with a PEDro-score of at least 5 points. Of these, three studies were excluded from the qualitative analysis because the necessary data, such as standard deviation or control group results, were missing. The effect sizes are very mixed. In some parameters there is no effect, in others a very strong effect. The effects in the comparison between single and multiple treatments are similar. Discussion: The different effects may be partly due to the different vibration frequencies or sentence durations, as well as to different valid test procedures. Conclusions: Since the study situation still does not show clear results, further studies must follow that compare different frequencies, sentence durations and vibration types with each other, so that training recommendations can be given on this basis.","PeriodicalId":75301,"journal":{"name":"Vibration","volume":"164 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135889330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-18DOI: 10.3390/vibration6040056
Nikolaos M. Papadakis, Nikolaos Nikolidakis, Georgios E. Stavroulakis
Cretan lyra is a stringed instrument very popular on the island of Crete, Greece, and an important part of its musical tradition. For stringed musical instruments, the air mode resonance plays a vital part in their sound, especially in the low frequency range. For this study, the air mode resonance of a Cretan lyra is investigated with the use of finite element method (FEM). Two different FEM acoustic models were utilized: First, a pressure acoustics model with the Cretan lyra body treated as rigid was used to provide an approximate result. Secondly, an acoustic–structure interaction model was applied for a more accurate representation. In addition, acoustic measurements were performed to identify the air mode resonance frequency. The results of this study reveal that the acoustic–structure interaction model has a 3.7% difference regarding the actual measurements of the resonance frequency. In contrast, the pressure acoustics solution is approximately 13.8% too high compared with the actual measurements. Taken together, the findings of this study support the idea that utilizing the FEM acoustic–structure interaction models could possibly predict the vibroacoustic behavior of musical instruments more accurately, which in turn can enable the determination of key aspects that can be used to control the instrument’s tone and sound quality.
{"title":"FEM Investigation of the Air Resonance in a Cretan Lyra","authors":"Nikolaos M. Papadakis, Nikolaos Nikolidakis, Georgios E. Stavroulakis","doi":"10.3390/vibration6040056","DOIUrl":"https://doi.org/10.3390/vibration6040056","url":null,"abstract":"Cretan lyra is a stringed instrument very popular on the island of Crete, Greece, and an important part of its musical tradition. For stringed musical instruments, the air mode resonance plays a vital part in their sound, especially in the low frequency range. For this study, the air mode resonance of a Cretan lyra is investigated with the use of finite element method (FEM). Two different FEM acoustic models were utilized: First, a pressure acoustics model with the Cretan lyra body treated as rigid was used to provide an approximate result. Secondly, an acoustic–structure interaction model was applied for a more accurate representation. In addition, acoustic measurements were performed to identify the air mode resonance frequency. The results of this study reveal that the acoustic–structure interaction model has a 3.7% difference regarding the actual measurements of the resonance frequency. In contrast, the pressure acoustics solution is approximately 13.8% too high compared with the actual measurements. Taken together, the findings of this study support the idea that utilizing the FEM acoustic–structure interaction models could possibly predict the vibroacoustic behavior of musical instruments more accurately, which in turn can enable the determination of key aspects that can be used to control the instrument’s tone and sound quality.","PeriodicalId":75301,"journal":{"name":"Vibration","volume":"126 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135890094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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