In this article, the nonlinear principal and internal resonance properties of a soft ferromagnetic rectangular thin plate are investigated in a magnetic field environment. The nonlinear partial differential equation of motion of a soft ferromagnetic rectangular thin plate is derived under the effect of homogeneous simple harmonic excitation. The system of nonlinear differential equations with multiple degrees of freedom is established by the assumed one-sided fixed trilateral simply support condition using the Galerkin’s method. The system of nonlinear differential equations is solved by the multiscale method to obtain the response of two modes under the simple harmonic force at the principal and internal resonance. The numerical results of the system response show that when the frequency of the simple harmonic force is close to one of the modes (first-order or second-order mode) causing it to resonate, the other mode will also resonate internally. The magnetic field can have an inhibiting effect on the resonant response of the system and also affect the kinematic state of the system. The internal resonance provides a mechanism for transferring energy from a high mode to a lower mode.
{"title":"Joint Resonance Analysis in Multiple Modes of Soft Ferromagnetic Rectangular Thin Plate","authors":"Xiaofang Kang, Xinzong Wang, Qingguan Lei, Zhengxing Zhu, Ziyi Sheng, Fuyi Zhang","doi":"10.13052/ejcm2642-2085.3311","DOIUrl":"https://doi.org/10.13052/ejcm2642-2085.3311","url":null,"abstract":"In this article, the nonlinear principal and internal resonance properties of a soft ferromagnetic rectangular thin plate are investigated in a magnetic field environment. The nonlinear partial differential equation of motion of a soft ferromagnetic rectangular thin plate is derived under the effect of homogeneous simple harmonic excitation. The system of nonlinear differential equations with multiple degrees of freedom is established by the assumed one-sided fixed trilateral simply support condition using the Galerkin’s method. The system of nonlinear differential equations is solved by the multiscale method to obtain the response of two modes under the simple harmonic force at the principal and internal resonance. The numerical results of the system response show that when the frequency of the simple harmonic force is close to one of the modes (first-order or second-order mode) causing it to resonate, the other mode will also resonate internally. The magnetic field can have an inhibiting effect on the resonant response of the system and also affect the kinematic state of the system. The internal resonance provides a mechanism for transferring energy from a high mode to a lower mode.","PeriodicalId":45463,"journal":{"name":"European Journal of Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140374164","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 : 2024-03-27DOI: 10.13052/ejcm2642-2085.3314
Zhenlong Tong, Zhongya Han, Zenglin Wu, Dongyu Yang
Utilizing the nonlinear finite element analysis software, ABAQUS, an examination is undertaken to evaluate the ductility characteristics and seismic design methodologies pertinent to a representative reinforced concrete hollow high pier. The research encompasses several focal areas: elucidation of seismic design strategies related to ductility categories, exploration of plastic energy dissipation mechanisms, determination of ductility indices, and delineation of structural measures to enhance ductility. Employing the nonlinear FEA software, ABAQUS, it is recommended that the longitudinal reinforcement ratio for ductile piers fall within the range of 0.6% to 4%. Furthermore, for flexible bridge piers, the maximum spacing of confinement reinforcements should either exceed 100 mm, be sixfold the diameter of the longitudinal reinforcement, or equate to at least one-quarter of the pier column’s bending direction section width. Combined with the influence of high pier ductility seismic axial pressure ratio, reinforcement, concrete factors such as factor analysis results, put forward and checking a reinforced concrete hollow high pier ductility seismic optimization scheme, increase the strength of the plastic hinge area section, through the comparative analysis in different seismic strength of plastic hinge unit cloth, maximum ductility coefficient and pier top displacement to verify its influence on the ductile seismic.
{"title":"Study on Seismic Mechanical Properties of Reinforced Concrete Energy Dissipation Wall and Seismic Response Analysis of Structure","authors":"Zhenlong Tong, Zhongya Han, Zenglin Wu, Dongyu Yang","doi":"10.13052/ejcm2642-2085.3314","DOIUrl":"https://doi.org/10.13052/ejcm2642-2085.3314","url":null,"abstract":"Utilizing the nonlinear finite element analysis software, ABAQUS, an examination is undertaken to evaluate the ductility characteristics and seismic design methodologies pertinent to a representative reinforced concrete hollow high pier. The research encompasses several focal areas: elucidation of seismic design strategies related to ductility categories, exploration of plastic energy dissipation mechanisms, determination of ductility indices, and delineation of structural measures to enhance ductility. Employing the nonlinear FEA software, ABAQUS, it is recommended that the longitudinal reinforcement ratio for ductile piers fall within the range of 0.6% to 4%. Furthermore, for flexible bridge piers, the maximum spacing of confinement reinforcements should either exceed 100 mm, be sixfold the diameter of the longitudinal reinforcement, or equate to at least one-quarter of the pier column’s bending direction section width. Combined with the influence of high pier ductility seismic axial pressure ratio, reinforcement, concrete factors such as factor analysis results, put forward and checking a reinforced concrete hollow high pier ductility seismic optimization scheme, increase the strength of the plastic hinge area section, through the comparative analysis in different seismic strength of plastic hinge unit cloth, maximum ductility coefficient and pier top displacement to verify its influence on the ductile seismic.","PeriodicalId":45463,"journal":{"name":"European Journal of Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140375878","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 : 2024-02-24DOI: 10.13052/ejcm2642-2085.3261
Xiaojian Xu, Guangtao Xin, Zhao Jian, Chen Yu
This article investigates the coupled vibration problem of suspension bridge structures under earthquake action, and conducts static and dynamic analysis using computer algorithms. In terms of static analysis, complex structures are divided into many small elements, and the stress and deformation of each element are calculated through finite element analysis, thereby obtaining the static characteristics of the entire structure. In terms of dynamic analysis, the seismic response analysis method based on time history considers seismic action as a time-varying external excitation, and calculates and simulates the dynamic response of the suspension bridge structure. In order to achieve efficient and accurate calculations, this article also adopts optimization algorithms and numerical calculation methods. Through a comprehensive study of statics and dynamics analysis, the key characteristics and regularities of coupled vibration of suspension bridge structures under earthquake action have been obtained. These research results not only provide important theoretical guidance and technical support for related engineering practices, but also provide useful references and inspirations for dynamic analysis and optimization design of similar structures. Meanwhile, using computer algorithms and simulation software for static and dynamic analysis can significantly reduce analysis costs and time, improve analysis accuracy and efficiency, and have broad application prospects.
{"title":"Static and Dynamic Analysis of Coupled Vibration of Suspension Bridge Structure Under Earthquake Action","authors":"Xiaojian Xu, Guangtao Xin, Zhao Jian, Chen Yu","doi":"10.13052/ejcm2642-2085.3261","DOIUrl":"https://doi.org/10.13052/ejcm2642-2085.3261","url":null,"abstract":"This article investigates the coupled vibration problem of suspension bridge structures under earthquake action, and conducts static and dynamic analysis using computer algorithms. In terms of static analysis, complex structures are divided into many small elements, and the stress and deformation of each element are calculated through finite element analysis, thereby obtaining the static characteristics of the entire structure. In terms of dynamic analysis, the seismic response analysis method based on time history considers seismic action as a time-varying external excitation, and calculates and simulates the dynamic response of the suspension bridge structure. In order to achieve efficient and accurate calculations, this article also adopts optimization algorithms and numerical calculation methods. Through a comprehensive study of statics and dynamics analysis, the key characteristics and regularities of coupled vibration of suspension bridge structures under earthquake action have been obtained. These research results not only provide important theoretical guidance and technical support for related engineering practices, but also provide useful references and inspirations for dynamic analysis and optimization design of similar structures. Meanwhile, using computer algorithms and simulation software for static and dynamic analysis can significantly reduce analysis costs and time, improve analysis accuracy and efficiency, and have broad application prospects.","PeriodicalId":45463,"journal":{"name":"European Journal of Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140433943","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 : 2024-02-24DOI: 10.13052/ejcm2642-2085.3263
Zhenlong Tong, Zenglin Wu, Dongyu Yang, Zhongya Han
This article aims to analyse the mechanical properties of FRP confined concrete core rods under cyclic loading. By observing the behaviour characteristics of FRP confined concrete core rods under different cyclic loads, the influence of FRP confinement on concrete cyclic loading is analysed. Based on theoretical analysis, this article establishes a corresponding mechanical model and analyses the response mechanism of FRP constraints to concrete cyclic loads through simulation calculations. Through experimental research and theoretical analysis, it is possible to fully understand the performance of new composite structural materials. The research results of this article indicate that the confinement of FRP bars can significantly improve the compressive strength of concrete specimens. At a constraint ratio of 20%, the compressive strength of the specimen increased by 30% compared to the unconstrained ratio; At 40%, the compressive strength increased by 50%, therefore, FRP confinement can significantly improve the ductility of concrete and reduce fatigue damage under cyclic loading. Through this research method, important evidence can be provided for the application of concrete in practical engineering.
{"title":"Analysis on Mechanical Properties of FRP Constrained Concrete Core Reinforcement Under Cyclic Load","authors":"Zhenlong Tong, Zenglin Wu, Dongyu Yang, Zhongya Han","doi":"10.13052/ejcm2642-2085.3263","DOIUrl":"https://doi.org/10.13052/ejcm2642-2085.3263","url":null,"abstract":"This article aims to analyse the mechanical properties of FRP confined concrete core rods under cyclic loading. By observing the behaviour characteristics of FRP confined concrete core rods under different cyclic loads, the influence of FRP confinement on concrete cyclic loading is analysed. Based on theoretical analysis, this article establishes a corresponding mechanical model and analyses the response mechanism of FRP constraints to concrete cyclic loads through simulation calculations. Through experimental research and theoretical analysis, it is possible to fully understand the performance of new composite structural materials. The research results of this article indicate that the confinement of FRP bars can significantly improve the compressive strength of concrete specimens. At a constraint ratio of 20%, the compressive strength of the specimen increased by 30% compared to the unconstrained ratio; At 40%, the compressive strength increased by 50%, therefore, FRP confinement can significantly improve the ductility of concrete and reduce fatigue damage under cyclic loading. Through this research method, important evidence can be provided for the application of concrete in practical engineering.","PeriodicalId":45463,"journal":{"name":"European Journal of Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140433966","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 : 2024-02-24DOI: 10.13052/ejcm2642-2085.3262
Yu Peng, Shuang Zhou
This study advances the use of high-strength concrete beams in structural engineering by analyzing their flexural behavior. Utilizing a combination of theoretical and empirical methods, the research develops equations for calculating the cracking moment and ultimate load capacity of these beams. Key findings include a shear-bearing capacity calculation model, validated by experimental data, with discrepancies in cracking moment and ultimate load-bearing capacity formulas being only 6.16% and 1.53% respectively. These results offer significant insights for the design and analysis of high-strength concrete beams in architectural engineering, demonstrating high accuracy and stability.
{"title":"Mechanical Behavior Analysis of High Strength Concrete Beams in Architectural Design: Simplified Calculation Method of Flexural and Shear Bearing Capacity","authors":"Yu Peng, Shuang Zhou","doi":"10.13052/ejcm2642-2085.3262","DOIUrl":"https://doi.org/10.13052/ejcm2642-2085.3262","url":null,"abstract":"This study advances the use of high-strength concrete beams in structural engineering by analyzing their flexural behavior. Utilizing a combination of theoretical and empirical methods, the research develops equations for calculating the cracking moment and ultimate load capacity of these beams. Key findings include a shear-bearing capacity calculation model, validated by experimental data, with discrepancies in cracking moment and ultimate load-bearing capacity formulas being only 6.16% and 1.53% respectively. These results offer significant insights for the design and analysis of high-strength concrete beams in architectural engineering, demonstrating high accuracy and stability.","PeriodicalId":45463,"journal":{"name":"European Journal of Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140434350","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 : 2024-02-24DOI: 10.13052/ejcm2642-2085.3264
Zhifang Ma, Shihao Zhang, Xiaoguang Guo
This article systematically studies the shear characteristics and structural mechanical response characteristics of composite beam joints. The results indicate that the shear stiffness of the connector is between 1000 N/mm and 2500 N/mm, with high stiffness performance. Meanwhile, as the stiffness increases, the frequency of the structure shows a significant increasing trend, indicating that high stiffness helps to improve the stability of the structure. In the trend chart of shear characteristics and performance of connectors over time, the shear characteristics of connectors significantly increased between 2018 and 2023, with an average shear strength increasing from 1500 N to 2100 N, an increase of 40%. By studying the static and dynamic response characteristics, as well as the bearing capacity, stability, and fatigue performance of composite beams. The results indicate that the response characteristics of the new connector are significantly better than those of traditional connectors. Based on the research results, this article proposes strategies and suggestions for optimizing connector design and improving overall structural performance, providing important theoretical support and practical guidance for practical engineering applications. This study not only enriches the theoretical system of composite beams, but also has important significance in promoting technological progress in related fields.
{"title":"Analysis on Shear Resistance of Joint and Structural Mechanical Response of Assembled Composite Beam Joints","authors":"Zhifang Ma, Shihao Zhang, Xiaoguang Guo","doi":"10.13052/ejcm2642-2085.3264","DOIUrl":"https://doi.org/10.13052/ejcm2642-2085.3264","url":null,"abstract":"This article systematically studies the shear characteristics and structural mechanical response characteristics of composite beam joints. The results indicate that the shear stiffness of the connector is between 1000 N/mm and 2500 N/mm, with high stiffness performance. Meanwhile, as the stiffness increases, the frequency of the structure shows a significant increasing trend, indicating that high stiffness helps to improve the stability of the structure. In the trend chart of shear characteristics and performance of connectors over time, the shear characteristics of connectors significantly increased between 2018 and 2023, with an average shear strength increasing from 1500 N to 2100 N, an increase of 40%. By studying the static and dynamic response characteristics, as well as the bearing capacity, stability, and fatigue performance of composite beams. The results indicate that the response characteristics of the new connector are significantly better than those of traditional connectors. Based on the research results, this article proposes strategies and suggestions for optimizing connector design and improving overall structural performance, providing important theoretical support and practical guidance for practical engineering applications. This study not only enriches the theoretical system of composite beams, but also has important significance in promoting technological progress in related fields.","PeriodicalId":45463,"journal":{"name":"European Journal of Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140435170","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 : 2023-12-30DOI: 10.13052/ejcm2642-2085.3251
Hafid Mataich, Bouchta El Amrani
In this study, we will evaluate the effect of bending/torsion coupling on the buckling instability and free vibration behavior of symmetrical laminated plates. We will load these plates in-plane with bi-axial or uni-axial, uniform or non-uniform mechanical loads. To quantify this behavior, we’ll compare the results obtained with those of specially orthotropic symmetrical plates (where bending/torsion coupling is absent). A parametric study will be carried out by varying the plate’s aspect ratio, anisotropy ratio and/or lamination angle. The aim of these studies is to construct a planar loading margin for the plate while remaining elastically stable, and to determine a physically admissible limit where we can approximate the behavior of symmetrical laminates to that of specially orthotropic plates (easy to study). We will base ourselves on a Rayleigh-Ritz energy formulation of the problem because of the difficulty of finding closed-form solutions. Following validation of this formulation, a numerical survey of the results will be carried out to quantify the effect of bending/torsion coupling on the instability of this type of plate. Various conditions on the plate boundaries will be used.
{"title":"The Impact of Flexural/Torsional Coupling on the Stability of Symmetrical Laminated Plates","authors":"Hafid Mataich, Bouchta El Amrani","doi":"10.13052/ejcm2642-2085.3251","DOIUrl":"https://doi.org/10.13052/ejcm2642-2085.3251","url":null,"abstract":"In this study, we will evaluate the effect of bending/torsion coupling on the buckling instability and free vibration behavior of symmetrical laminated plates. We will load these plates in-plane with bi-axial or uni-axial, uniform or non-uniform mechanical loads. To quantify this behavior, we’ll compare the results obtained with those of specially orthotropic symmetrical plates (where bending/torsion coupling is absent). A parametric study will be carried out by varying the plate’s aspect ratio, anisotropy ratio and/or lamination angle. The aim of these studies is to construct a planar loading margin for the plate while remaining elastically stable, and to determine a physically admissible limit where we can approximate the behavior of symmetrical laminates to that of specially orthotropic plates (easy to study). We will base ourselves on a Rayleigh-Ritz energy formulation of the problem because of the difficulty of finding closed-form solutions. Following validation of this formulation, a numerical survey of the results will be carried out to quantify the effect of bending/torsion coupling on the instability of this type of plate. Various conditions on the plate boundaries will be used.","PeriodicalId":45463,"journal":{"name":"European Journal of Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139140755","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 : 2023-12-30DOI: 10.13052/ejcm2642-2085.3253
Alexander Kevin, M. Akbar, Leonardo Gunawan, Darryl Khalid Aulia, Rizqy Agung, S. S. Rawikara, R. A. Sasongko, D. Widagdo
In the present work, a new study on the piezoelectric-based structure by means of Finite Element Method (FEM) is conducted. Currently, the piezoelectric model in the FEM-based commercial software is only applicable via 2D plane stress and 3D solid elements. However, piezoelectric structures are usually manufactured as thin-walled structures, i.e., plates and disks. Therefore, it is more convenient to model a piezoelectric-based structure with 2D shell elements. In this study, FEM with a thermal analogy approach is implemented. Thermal coupling characteristics are utilised as the equivalent of electromechanical properties. Thermal analysis is much more established in FEM-based software; thus, applications with various types of elements are enabled. Therefore, the evaluation of piezoelectric structure via shell element with a thermal analogy approach could be performed. Static and dynamic analyses are conducted with experimental and numerical validations. As depicted in some details in this paper, the shell model with thermal analogy shows an excellent agreement with the 3D solid piezoelectric elements with insignificant variances, less than 0.3%.
{"title":"Evaluation of Piezoelectric-based Composite for Actuator Application via FEM with Thermal Analogy","authors":"Alexander Kevin, M. Akbar, Leonardo Gunawan, Darryl Khalid Aulia, Rizqy Agung, S. S. Rawikara, R. A. Sasongko, D. Widagdo","doi":"10.13052/ejcm2642-2085.3253","DOIUrl":"https://doi.org/10.13052/ejcm2642-2085.3253","url":null,"abstract":"In the present work, a new study on the piezoelectric-based structure by means of Finite Element Method (FEM) is conducted. Currently, the piezoelectric model in the FEM-based commercial software is only applicable via 2D plane stress and 3D solid elements. However, piezoelectric structures are usually manufactured as thin-walled structures, i.e., plates and disks. Therefore, it is more convenient to model a piezoelectric-based structure with 2D shell elements. In this study, FEM with a thermal analogy approach is implemented. Thermal coupling characteristics are utilised as the equivalent of electromechanical properties. Thermal analysis is much more established in FEM-based software; thus, applications with various types of elements are enabled. Therefore, the evaluation of piezoelectric structure via shell element with a thermal analogy approach could be performed. Static and dynamic analyses are conducted with experimental and numerical validations. As depicted in some details in this paper, the shell model with thermal analogy shows an excellent agreement with the 3D solid piezoelectric elements with insignificant variances, less than 0.3%.","PeriodicalId":45463,"journal":{"name":"European Journal of Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139138222","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 : 2023-12-30DOI: 10.13052/ejcm2642-2085.3252
Zhenguo Xu, Ayush Maria, Kahina Chelli, Thibaut Dumouchel De Premare, Xabadin Bilbao, Christopher Petit, Robert Zoumboulis-Airey, Irene Moulitsas, Tom-Robin Teschner, Seemal Asif, Jun Li
The identification of vortices and cores is crucial for understanding airflow motion in aerodynamics. Currently, numerous methods in Computer Vision and Machine Learning exist for detecting vortices and cores. This research develops a comprehensive framework by combining classic Computer Vision and state-of-the-art Machine Learning techniques for vortex and core detection. It enhances a CNN-based method using Computer Vision algorithms for Feature Engineering and then adopts an Ensemble Learning approach for vortex core classification, through which false positives, false negatives, and computational costs are reduced. Specifically, four features, i.e., Contour Area, Aspect Ratio, Area Difference, and Moment Centre, are employed to identify vortex regions using YOLOv5s, followed by a hard voting classifier based on Random Forest, Adaptive Boosting, and Xtreme Gradient Boosting algorithms for vortex core detection. This novel approach differs from traditional Computer Vision approaches using mathematical variables and image features such as HAAR and SIFT for vortex core detection. The findings show that vortices are detected with a high degree of statistical confidence by a fine-tuned YOLOv5s model, and the integrated technique produces an accuracy score of 97.56% in detecting vortex cores conducted on a total of 133 images generated from a rotor blade NACA0012 simulation. Future work will focus on framework generalisation with a larger and more diverse dataset and intelligent threshold development for more efficient vortex and core detection.
{"title":"Vortex and Core Detection using Computer Vision and Machine Learning Methods","authors":"Zhenguo Xu, Ayush Maria, Kahina Chelli, Thibaut Dumouchel De Premare, Xabadin Bilbao, Christopher Petit, Robert Zoumboulis-Airey, Irene Moulitsas, Tom-Robin Teschner, Seemal Asif, Jun Li","doi":"10.13052/ejcm2642-2085.3252","DOIUrl":"https://doi.org/10.13052/ejcm2642-2085.3252","url":null,"abstract":"The identification of vortices and cores is crucial for understanding airflow motion in aerodynamics. Currently, numerous methods in Computer Vision and Machine Learning exist for detecting vortices and cores. This research develops a comprehensive framework by combining classic Computer Vision and state-of-the-art Machine Learning techniques for vortex and core detection. It enhances a CNN-based method using Computer Vision algorithms for Feature Engineering and then adopts an Ensemble Learning approach for vortex core classification, through which false positives, false negatives, and computational costs are reduced. Specifically, four features, i.e., Contour Area, Aspect Ratio, Area Difference, and Moment Centre, are employed to identify vortex regions using YOLOv5s, followed by a hard voting classifier based on Random Forest, Adaptive Boosting, and Xtreme Gradient Boosting algorithms for vortex core detection. This novel approach differs from traditional Computer Vision approaches using mathematical variables and image features such as HAAR and SIFT for vortex core detection. The findings show that vortices are detected with a high degree of statistical confidence by a fine-tuned YOLOv5s model, and the integrated technique produces an accuracy score of 97.56% in detecting vortex cores conducted on a total of 133 images generated from a rotor blade NACA0012 simulation. Future work will focus on framework generalisation with a larger and more diverse dataset and intelligent threshold development for more efficient vortex and core detection.","PeriodicalId":45463,"journal":{"name":"European Journal of Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139139580","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: 10.13052/ejcm2642-2085.3244
Ahmed Saimi, Ismail Bensaid, Besma Khouani, Med Yassin Mazari, Ihab Eddine Houalef, Abdelmadjid Cheikh
The free vibration and buckling behaviours of 2D-FG porous microbeams are explored in this paper utilizing the Quasi-3D beam deformation theory based on the modified couple stress theory and a Differential Quadrature Galerkin Method (DQGM) systematically, as a combination of the Differential Quadrature Method (DQM) and the semi-analytical Galerkin method, which has used to reduce computational cost for problems in dynamics. The governing equations are obtained using the Lagrange’s principle. The mass and stiffness matrices are calculated using the weighting coefficient matrices given by the differential quadrature (DQ) and Gauss-Lobatto quadrature rules. The matrices are expressed in a similar form to that of the Differential Quadrature Method by introducing an interpolation basis on the element boundary of the Galerkin method. The sampling points are determined by the Gauss-Lobatto node method. The influence of the thickness-to-material length scale parameter (MLSP) on the nondimensional natural frequencies and nondimensional critical buckling loads of 2D-FG porous microbeams are investigated, along with the effects of the boundary condition, aspect ratio and gradient index. The results are validated with literature to establish the accuracy of the procedure described. This work will provide a numerical basis for the design of FG microstructures in the field of micromechanics. These results can be applied to the engineering design of porous FG microstructures.
{"title":"A Novel Differential Quadrature Galerkin Method for Dynamic and Stability Behaviour of Bi-directional Functionally Graded Porous Micro Beams","authors":"Ahmed Saimi, Ismail Bensaid, Besma Khouani, Med Yassin Mazari, Ihab Eddine Houalef, Abdelmadjid Cheikh","doi":"10.13052/ejcm2642-2085.3244","DOIUrl":"https://doi.org/10.13052/ejcm2642-2085.3244","url":null,"abstract":"The free vibration and buckling behaviours of 2D-FG porous microbeams are explored in this paper utilizing the Quasi-3D beam deformation theory based on the modified couple stress theory and a Differential Quadrature Galerkin Method (DQGM) systematically, as a combination of the Differential Quadrature Method (DQM) and the semi-analytical Galerkin method, which has used to reduce computational cost for problems in dynamics. The governing equations are obtained using the Lagrange’s principle. The mass and stiffness matrices are calculated using the weighting coefficient matrices given by the differential quadrature (DQ) and Gauss-Lobatto quadrature rules. The matrices are expressed in a similar form to that of the Differential Quadrature Method by introducing an interpolation basis on the element boundary of the Galerkin method. The sampling points are determined by the Gauss-Lobatto node method. The influence of the thickness-to-material length scale parameter (MLSP) on the nondimensional natural frequencies and nondimensional critical buckling loads of 2D-FG porous microbeams are investigated, along with the effects of the boundary condition, aspect ratio and gradient index. The results are validated with literature to establish the accuracy of the procedure described. This work will provide a numerical basis for the design of FG microstructures in the field of micromechanics. These results can be applied to the engineering design of porous FG microstructures.","PeriodicalId":45463,"journal":{"name":"European Journal of Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135775781","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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