Applied and Computational Mechanics最新文献

{"title":"A Nonlinear Error Compensator for FDM 3D Printed Part Dimensions Using a Hybrid Algorithm Based on GMDH Neural Network","authors":"Hamid Haghshenas Gorgani, H. Korani, Reihaneh Jahedan, Sharif Shabani","doi":"10.22059/JCAMECH.2021.325325.628","DOIUrl":"https://doi.org/10.22059/JCAMECH.2021.325325.628","url":null,"abstract":"Following the advances in Computer-Aided Design (CAD) and Additive Manufacturing (AM), with regards to the numerous benefits of the Fused Deposition Modeling (FDM) as a popular AM process, resolving its weaknesses has become increasingly important. A serious problem of the FDM is the dimensional error or size difference between the CAD model and the actual 3D printed part.In this study, the approach is compensating the error regardless of its source. At First, all parameters affecting the dimensional accuracy of FDM are comprehensively identified. Then, multi-input–single-output (MISO) data is prepared by designing experiments using the Taguchi method and obtaining the results from 3D printed samples. Next, a GMDH neural network is applied, which uses a simple nonlinear regression formula in each neuron but can create very complex neuron combinations. So, it is possible to analyze small or even noisy data. Regulatory parameters of the Neural Net have been optimized to increase efficiency. The case study shows a decrease in the RSME for the Nominal CAD Model from 0.377 to 0.033, displaying the compensator's efficiency.","PeriodicalId":37801,"journal":{"name":"Applied and Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48252534","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}

{"title":"Forced vibration of a magnetoelastic laminated composite beam on Pasternak’s foundation","authors":"A. Zenkour, H. El-Shahrany","doi":"10.22059/JCAMECH.2021.326538.636","DOIUrl":"https://doi.org/10.22059/JCAMECH.2021.326538.636","url":null,"abstract":"Vibrational behavior prediction of a laminated composite beam on Winkler-Pasternak’s medium is analyzed in the present article. The proposed beam contains four smart actuating layers of magnetostrictive material to vibration control of the system with a simple constant feedback control gain distribution. The designed structure undergoes an external force in x direction and a magnetic field. A higher-order shear deformation theory with an exponential shape function is used to model the proposed system. Hamilton’s principle and Navier’s approach are used to obtain and solve the dynamic system. The natural frequencies, deflections, and suppression time of the studied system are computed for different thickness ratios, ply orientations, number and location of the magnetostrictive layers, foundation stiffness, velocity feedback gain value, and external force.","PeriodicalId":37801,"journal":{"name":"Applied and Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49466757","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}

{"title":"Nonlocal effect on the axisymmetric nonlinear vibrational response of nano-disks using variational iteration method","authors":"M. Shariati, M. Shishesaz, R. Mosalmani, S. A. S. Roknizadeh, M. Hosseini","doi":"10.22059/JCAMECH.2021.305561.525","DOIUrl":"https://doi.org/10.22059/JCAMECH.2021.305561.525","url":null,"abstract":"In this study, the nonlinear free vibration of a nano-disk considering small scale effects has been investigated by using the nonlocal elasticity. To take into account the nonlinear geometric effects, the nonlinear model of von Karman strain has been used while the governing differential equation was extracted according to Hamilton principle. The Galerkin weighted residual method in conjunction with the variational iteration method (VIM) was introduced to solve the governing equations for simply supported and clamped edge boundary conditions. For further comparison, the nonlinear equation was solved using the fourth-order Runge-Kutta method. Very good agreements were observed between the results of both methods, while the former method made the solution much easier. Additionally, it was observed that the ratio of thickness to radius, h/R, plays an important role on the nonlinear frequencies. This effect appears to be minute if the local elasticity theory is adopted. However, results indicated that the nonlocal effect may be ignored provided h/R ratio is very small.","PeriodicalId":37801,"journal":{"name":"Applied and Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44629774","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}

{"title":"Dynamic Response of Functionally Graded Carbon Nanotube-Reinforced Hybrid Composite Plates","authors":"Chun-Sheng Chen, C. Fung, Hai Wang, Wei-Ren Chen","doi":"10.22055/JACM.2021.37884.3108","DOIUrl":"https://doi.org/10.22055/JACM.2021.37884.3108","url":null,"abstract":"Dynamic instability behavior of functionally graded carbon nanotube reinforced hybrid composite plates subjected to periodic loadings is studied. The governing equations of motion of Mathieu-type are established by using the Galerkin method with reduced eigenfunctions transforms. With the Mathieu equations, the dynamic instability regions of hybrid nanocomposite plates are determined by using the Bolotin’s method. Results reveal that the dynamic instability is significantly affected by the carbon nanotube volume fraction, layer thickness ratio, bending stress, static and dynamic load parameters. The effects of important parameters on the instability region and dynamic instability index of hybrid nanocomposite plates are discussed.","PeriodicalId":37801,"journal":{"name":"Applied and Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48265618","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}

{"title":"A comparative study of crack detection in nanobeams using molecular dynamics simulation, analytical formulations, and finite element method","authors":"Seyyed Sajad Mousavi Nejad Souq, Faramarz Ashenai Ghasemi, M. M. S. Fakhrabadi","doi":"10.22059/JCAMECH.2021.322563.613","DOIUrl":"https://doi.org/10.22059/JCAMECH.2021.322563.613","url":null,"abstract":"The study of material behavior in the presence of defects is one of the studies that can help us recognize and predict material behavior. Studying the behavior of materials in nanoscale illuminates a broad view of the behavior of materials. A variety of studies are available for such a study: numerical, experimental, and quasi-experimental methods. Molecular dynamics is one of the methods that can be used to study the behavior of materials. The vibrational behavior of structures has been the focus of many researchers to analyze and investigate mortar materials' properties. The study of vibrational behavior at the nanoscale can give us a broad view of materials' properties. Therefore, in this study, we study nanowires' vibrational behavior in the presence of edge cracks using molecular dynamics. The influence of crack position and depth on the natural frequencies and shape of iron nanobeam modes with BCC crystal structure have been investigated. Clamped-Clamped boundary conditions with different cracks position and depth have been applied by simulating molecular dynamics. Also, the data obtained from molecular dynamics simulations have been compared with the finite element method and different crack models in one dimensional beams . In order to extract the shape of natural modes and frequencies by molecular dynamics method, FFT applied on the  displacement history of nanobeam atoms after excitation of an amplitude in the center of nanobeam in x and y directions have been used. The crack models studied in this study were linear and rotational crack models on beams with Timoshenko theory. Molecular dynamics simulation data compared to other methods have shown a decrease in the value of natural frequencies in the presence of cracks. Also, finite element data and molecular dynamics are well matched. However, the molecular dynamics method has shown a more significant reduction in natural frequency values   than finite element methods and various crack models with Timoshenko theory. We have also found that in molecular dynamics bribery, the initial excitation type of nanobeams is very useful in extracting nanobeam modes' shape.","PeriodicalId":37801,"journal":{"name":"Applied and Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44417774","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}

{"title":"On the Analytical and Computational Methodologies for Modelling Two-wheeled Vehicles within the Multibody Dynamics Framework: A Systematic Literature Review","authors":"C. A. Manrique-Escobar, C. Pappalardo, D. Guida","doi":"10.22055/JACM.2021.37935.3118","DOIUrl":"https://doi.org/10.22055/JACM.2021.37935.3118","url":null,"abstract":"In this paper, a literature review on two-wheeled vehicle systems is methodically performed and presented. For this purpose, the principal aspects concerning the kinematic, dynamic, control, and identification features of articulated mechanical systems described within the multibody formulation approach are emphasized in this review article. First, the scientific investigations on two-wheeled vehicle modelling are chronologically described employing a historical literature review approach. This is done to set a consistent context for the subsequent developments analyzed in the paper. Then, following the systematic literature review methodology described in this work, a rich corpus of relevant documents in the time span between 2013-present. Moreover, bibliometric methods are used to construct the conceptual structure map of the research field, which also allowed for formulating a thematic classification. Thus, considering the full-texts of the identified corpus of documents, this work presents a synthetic analysis of the fundamental issues about the multibody approaches for modelling two-wheeled vehicles. Finally, future research perspectives are pointed out in this article","PeriodicalId":37801,"journal":{"name":"Applied and Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47094455","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}

{"title":"WaveMIMO Methodology: Numerical Wave Generation of a Realistic Sea State","authors":"B. N. Machado, P. Oleinik, Eduardo de Paula Kirinus, E. D. Santos, L. Rocha, M. N. Gomes, J. Conde, L. Isoldi","doi":"10.22055/JACM.2021.37617.3051","DOIUrl":"https://doi.org/10.22055/JACM.2021.37617.3051","url":null,"abstract":"This paper presents a methodology that allows the numerical simulation of realistic sea waves, called WaveMIMO methodology, which is based on the imposition of transient discrete data as prescribed velocity on a finite volume computational model developed in Fluent software. These transient data are obtained by using the spectral wave model TOMAWAC, where the wave spectrum is converted into a series of free surface elevations treated and processed as wave propagation velocities in the horizontal (x) and vertical (z) directions. The processed discrete transient data of wave propagation velocity are imposed as boundary conditions of a wave channel in Fluent, allowing the numerical simulation of irregular waves with realistic characteristics. From a case study that reproduces the sea state occurring on March 31st, 2014, in Ingleses Beach, in the city of Florianopolis, state of Santa Catarina, Brazil, it was concluded that the WaveMIMO methodology can properly reproduce realistic conditions of a sea state. In sequence, the proposed methodology was employed to numerically simulate the incidence of irregular realistic waves over an oscillating water column (OWC) wave energy converter (WEC). From these results, the WaveMIMO methodology has proved to be a promising technique to numerically analyze the fluid-dynamic behavior of WECs subjected to irregular waves of realistic sea state on any coastal region where the device can be installed.","PeriodicalId":37801,"journal":{"name":"Applied and Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48234220","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}

{"title":"Numerical Study on the Ferrofluid Droplet Splitting in a T-junction with Branches of Unequal Widths using Asymmetric Magnetic Field","authors":"M. Aboutalebi, M. Shafii, S. Hannani","doi":"10.22055/JACM.2021.36722.2892","DOIUrl":"https://doi.org/10.22055/JACM.2021.36722.2892","url":null,"abstract":"Research on the microdroplet splitting phenomenon has intensified in recent years. Microdroplet splitting has numerous applications in chemical synthesis, biology, and separation processes. The current paper covers the numerical study of ferrofluid microdroplet splitting at various lengths and velocities inside the T-junction with branches of unequal widths under asymmetric magnetic fields. Microdroplet splitting can be controlled by using an asymmetric magnetic field and the asymmetry in the width of T-junctions branches. Three geometrical models of the T-junction with different widths ratio (0.7, 0.85, and 1), along with a magnetic field with various intensities are studied. This magnetic field is generated by a line dipole. In this study, the distance between the dipole and origin is kept constant. The splitting ratio of ferrofluid microdroplets at different velocities (different capillary numbers), different non-dimensional lengths and different magnetic force (different magnetic Bond numbers) at the center of T-junction are calculated for each amount of branch width. The results are verified with previous works and their correctness is proved. The splitting ratio is defined as the volumetric ratio of the larger daughter droplet to the mother droplet. The results indicate that generally, the stronger the asymmetric magnetic force is, the more asymmetric the splitting will become, with the splitting ratio becoming closer to 1. Also, as asymmetry increases between the widths of the two branches of the T-junction, the splitting ratio approaches 1.","PeriodicalId":37801,"journal":{"name":"Applied and Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42476619","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}

{"title":"Effect of the Gravity and Magnetic Field to Find Regular Precessions of a Satellite-gyrostat with Principal Axes on a Circular Orbit","authors":"H. Yehia, H. N. El-kenani","doi":"10.22055/JACM.2021.37913.3113","DOIUrl":"https://doi.org/10.22055/JACM.2021.37913.3113","url":null,"abstract":"We consider the motion of a magnetized satellite-gyrostat in a circular orbit due to the combined influence of uniform gravity and magnetic fields. Based on the Lagrangian equations, the necessary conditions for the existence of regular precessions are determined in which the axis of precession is perpendicular to the orbital plane. All possible regular precessions and permanent rotations are determined and classified. We show the usage of Lagrange equations taking Eulerian angles as generalized coordinates for determining the regular precessions is more effective and accurate than utilization of Euler-Poisson equations.","PeriodicalId":37801,"journal":{"name":"Applied and Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45735811","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}

{"title":"Natural Magneto-velocity Coordinate System for Satellite Attitude Stabilization: The Concept and Kinematic Analysis","authors":"A. Tikhonov","doi":"10.22055/JACM.2021.37817.3094","DOIUrl":"https://doi.org/10.22055/JACM.2021.37817.3094","url":null,"abstract":"An artificial Earth satellite with an electric charge and an intrinsic magnetic moment is considered. Due to the geomagnetic field, the satellite experiences the influence of the Lorentz and magnetic torques. To set the angular position of the satellite, we introduce natural coordinate system associated with the directions of geomagnetic induction vector and Lorentz force vector which is orthogonal both to the geomagnetic induction and relative velocity of the satellite. It is shown that such a natural magneto-velocity coordinate system is convenient for attitude stabilization of a satellite operating in the mode of scanning the Earth's surface. The properties of the trajectory of the satellite axis on the Earth's surface are analysed. The rotation tensor connecting the natural magneto-velocity and the orbital coordinate systems is obtained. The angular velocity of the natural magneto-velocity trihedron is found. Kinematic differential equations for the unit vectors of the natural magneto-velocity coordinate system are derived.","PeriodicalId":37801,"journal":{"name":"Applied and Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46666981","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}