scholarly journals Identification of Three-Dimensional Equivalent Material Properties for Laminated Disks Pack of Electric Machine Stators: Application in Reciprocal Compressors

2019 ◽  
Vol 2019 ◽  
pp. 1-18
Author(s):  
Jean C. Marcon ◽  
Olavo M. Silva ◽  
Thiago A. Fiorentin ◽  
Arcanjo Lenzi
Keyword(s):  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Magnetic Core ◽  
Synthesis Methods ◽  
Equivalent Material ◽  
The Difference ◽  
Three Dimensional Models ◽  
Orthotropic Properties ◽  
Definition Of ◽  
Laminated Structures

Laminated structures can be represented computationally by the finite element method (FEM) using the homogenization procedure, which consists of the adjustment of equivalent orthotropic properties to a homogeneous structure. The application occurs in stators of electric machines composed of stacked laminated disks connected to each other through windings and other fastening components. This paper describes a method to the dynamic characterization of a typical laminated stator through the application of the homogenization technique to the magnetic core and consideration of the effect of winding contour conditions and screw joints. Two simplified three-dimensional models for the stator were compared. The first considers the application of a typical tightening of the fastening screws and the presence of a homogeneous isotropic volume representing the winding. The second considers the effect of the boundary condition of the winding on the region of the teeth of the nucleus in order to reduce the degrees of freedom of the complete model. The coupling between the components is accomplished through the application of modal synthesis methods, which require the definition of the surfaces and the type of connection between the components. The obtainment of the set of equivalent orthotropic properties is based on the minimization of residues related to the difference between the natural and experimental frequencies in the range of 0 to 10 kHz. This was carried out using the multiobjective genetic algorithm (MOGA) method used in conjunction with commercial Ansys® software. Both models presented satisfactory experimental correlation. The simplified model demonstrated limitations of representativeness emphasized in specific frequency bands.

scholarly journals Comparative Evaluation of Biomechanical Performance of Titanium and Stainless Steel Mini Implants at Different Angulations in Maxilla: A Finite Element Analysis

2019 ◽  
Vol 53 (3) ◽  
pp. 197-205
Author(s):  
Kshitij Hemant Sabley ◽  
Usha Shenoy ◽  
Sujoy Banerjee ◽  
Pankaj Akhare ◽  
Ananya Hazarey ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Titanium Implant ◽  
Titanium Implants ◽  
Element Analysis ◽  
Mini Implants ◽  
The Difference ◽  
Tractional Forces ◽  
Three Dimensional Models

Objective: To assess and compare the tensions and deformations (stresses and strains) generated after application of two types of forces (traction and torsion) in miniscrews of two different materials (titanium and stainless steel) placed at five different angulations. Materials and Methods: Three-dimensional models of the posterior maxillary area and the mini-implants were constructed using computer-aided design software program (CATIA P3 V5-6 R2015 B26 / 2016; Dassault Systèmes). Titanium and stainless steel materials were used for miniscrews. The area constructed was in between the maxillary second premolar and first molar. The models with mini-implants were inserted at five different angulations (30°, 45°, 60°, 75° and 90°). Torsional and tractional forces were applied on these implants, and the models were solved using ANSYS 10.0. Stress generated in implant and in the cortical and cancellous bones was evaluated and compared at all the five angulations. Results: Stress generated in stainless steel mini-implant during torsional and linear force application was less when compared with titanium mini-implant. Also, stress generated in implants of both materials increased as the angle increased from 30° to 90°. Difference in stress generated by stainless steel implant in the cortical bone for both linear and torsional forces was less when compared with titanium implant, whereas for cancellous bone, the difference was insignificant at all the angles. Conclusion: Irrespective of angles, difference in stress generated in stainless steel implants and titanium implants for both the forces was not significant, and hence, stainless steel implants can be used effectively in a clinical setting.

Smooth 3D manifolds based on thin plates

2016 ◽  
Vol 22 (3) ◽  
pp. 477-490
Author(s):  
VA Grachev ◽  
YS Neustadt
Keyword(s):  
Degrees Of Freedom ◽  
3D Structure ◽  
Three Dimensional ◽  
Small Diameter ◽  
Thin Plates ◽  
Mechanics Of Solids ◽  
Dimensional Manifold ◽  
Initial State ◽  
Rigid Plastic ◽  
Definition Of

This paper demonstrates a fractal system of thin plates connected with hinges. The system can be studied using the methods of the mechanics of solids with internal degrees of freedom. The structure is deployable, and initially, it is similar to a small-diameter one-dimensional manifold, which occupies significant volume after deployment. The geometry of solids is studied using the method of the moving hedron. The relationships enabling the definition of the geometry of the introduced manifolds are derived based on the Cartan structure equations. The proof substantially makes use of the fact that the fractal consists of thin plates that are not long compared to the sizes of the system. The mechanics are described for solids with rigid plastic hinges between the plates, and the hinges are made of shape memory material. Based on the ultimate load theorems, estimates are performed to specify the internal pressure that is required to deploy the package into a three-dimensional (3D) structure and the heat input needed to return the system into its initial state. Some possible applications of the smooth 3D manifolds are demonstrated.

scholarly journals Numerical Analysis of the Brittle-Ductile Transition in the Failure-Mode in Polymeric Materials

2014 ◽  
Vol 566 ◽  
pp. 310-315
Author(s):  
Josué Aranda-Ruiz ◽  
J.A. Loya
Keyword(s):  
Failure Mode ◽  
Damage Model ◽  
Three Dimensional ◽  
Polymeric Materials ◽  
Material Behavior ◽  
The Finite Element Method ◽  
Brittle Ductile Transition ◽  
User Subroutine ◽  
The Difference ◽  
Three Dimensional Models

In this paper we analyze, using the Finite Element Method, the process of brittle-ductile transition in the failure mode observed in polycarbonate notched specimens under impact loads. In order to analyze this transition we have implemented, through a user subroutine, a damage model which combines a tensional fracture criterion and an energetic, acting simultaneously. The competition between both criteria predicts the difference in material behavior from a critical impact velocity, and how this transition is produced on different planes through the thickness of the specimen. These results show the necessity of employing three-dimensional models for its study.

On a Leray–α model of turbulence

2005 ◽  
Vol 461 (2055) ◽  
pp. 629-649 ◽  
Author(s):  
Alexey Cheskidov ◽  
Darryl D. Holm ◽  
Eric Olson ◽  
Edriss S. Titi
Keyword(s):  
Power Law ◽  
Upper Bound ◽  
Empirical Data ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Large Eddy Simulation Model ◽  
Eddy Simulation ◽  
Wide Range ◽  
Three Dimensional Models

In this paper we introduce and study a new model for three–dimensional turbulence, the Leray– α model. This model is inspired by the Lagrangian averaged Navier–Stokes– α model of turbulence (also known Navier–Stokes– α model or the viscous Camassa–Holm equations). As in the case of the Lagrangian averaged Navier–Stokes– α model, the Leray– α model compares successfully with empirical data from turbulent channel and pipe flows, for a wide range of Reynolds numbers. We establish here an upper bound for the dimension of the global attractor (the number of degrees of freedom) of the Leray– α model of the order of ( L / l d ) 12/7 , where L is the size of the domain and l d is the dissipation length–scale. This upper bound is much smaller than what one would expect for three–dimensional models, i.e. ( L / l d ) 3 . This remarkable result suggests that the Leray– α model has a great potential to become a good sub–grid–scale large–eddy simulation model of turbulence. We support this observation by studying, analytically and computationally, the energy spectrum and show that in addition to the usual k −5/3 Kolmogorov power law the inertial range has a steeper power–law spectrum for wavenumbers larger than 1/ α . Finally, we propose a Prandtl–like boundary–layer model, induced by the Leray– α model, and show a very good agreement of this model with empirical data for turbulent boundary layers.

scholarly journals AUTOMATICALLY DETERMINING SCALE WITHIN UNSTRUCTURED POINT CLOUDS

2016 ◽  
Vol XLI-B3 ◽  
pp. 617-624
Author(s):  
Jayren Kadamen ◽  
George Sithole
Keyword(s):  
Three Dimensional ◽  
Point Clouds ◽  
Indoor Navigation ◽  
Indoor Environments ◽  
Terrestrial Lidar ◽  
Detection Of Objects ◽  
The Difference ◽  
Computationally Intensive ◽  
Three Dimensional Models ◽  
General Size

Three dimensional models obtained from imagery have an arbitrary scale and therefore have to be scaled. Automatically scaling these models requires the detection of objects in these models which can be computationally intensive. Real-time object detection may pose problems for applications such as indoor navigation. This investigation poses the idea that relational cues, specifically height ratios, within indoor environments may offer an easier means to obtain scales for models created using imagery. The investigation aimed to show two things, (a) that the size of objects, especially the height off ground is consistent within an environment, and (b) that based on this consistency, objects can be identified and their general size used to scale a model. To test the idea a hypothesis is first tested on a terrestrial lidar scan of an indoor environment. Later as a proof of concept the same test is applied to a model created using imagery. The most notable finding was that the detection of objects can be more readily done by studying the ratio between the dimensions of objects that have their dimensions defined by human physiology. For example the dimensions of desks and chairs are related to the height of an average person. In the test, the difference between generalised and actual dimensions of objects were assessed. A maximum difference of 3.96% (2.93<i>cm</i>) was observed from automated scaling. By analysing the ratio between the heights (distance from the floor) of the tops of objects in a room, identification was also achieved.

scholarly journals METHODS FOR MODELS PARAMETERS ESTIMATE TO SOLVE PROBLEMS ON 3D RECONSTRUCTION OF REAL OBJECTS COMPLEX MODELS

2016 ◽  
Vol 2016 (3) ◽  
pp. 233-242 ◽  
Author(s):  
Владислав Колякин ◽  
Vladislav Kolyakin ◽  
Владимир Аверченков ◽  
Vladimir Averchenkov ◽  
Максим Терехов ◽  
...  
Keyword(s):  
Computer Games ◽  
Three Dimensional ◽  
3D Models ◽  
Model Parameters ◽  
Complex Objects ◽  
Image Brightness ◽  
Real Objects ◽  
Complex Models ◽  
Three Dimensional Models ◽  
Definition Of

Virtual threedimensional (3 D) models of complex objects are used in many fields of science and engineering, such as architecture, industry, medicine, robotics. Besides, 3D models are used in geoinformation systems, computer games, virtual and supplemented reality and so on. Three dimensional models can be formed in dif-ferent ways, one of which consists in 3 D reconstruc-tion. One of the stages of the 3 D reconstruction of complex models of real objects is a definition of the mathematical models of geometric primitives emphasized on the image. One of the ways for the estimate of model parameters is a method of Hough vote and its modifications – Hough probabilistic transformation, Hough random transformation, Hough hierarchical transformation, phase space blurriness, use of a gra-dient of image brightness and so on. As an alternative way for models selection is a choice of suitable points from a set of data.

scholarly journals AUTOMATICALLY DETERMINING SCALE WITHIN UNSTRUCTURED POINT CLOUDS

2016 ◽  
Vol XLI-B3 ◽  
pp. 617-624
Author(s):  
Jayren Kadamen ◽  
George Sithole
Keyword(s):  
Three Dimensional ◽  
Point Clouds ◽  
Indoor Navigation ◽  
Indoor Environments ◽  
Terrestrial Lidar ◽  
Detection Of Objects ◽  
The Difference ◽  
Computationally Intensive ◽  
Three Dimensional Models ◽  
General Size

Three dimensional models obtained from imagery have an arbitrary scale and therefore have to be scaled. Automatically scaling these models requires the detection of objects in these models which can be computationally intensive. Real-time object detection may pose problems for applications such as indoor navigation. This investigation poses the idea that relational cues, specifically height ratios, within indoor environments may offer an easier means to obtain scales for models created using imagery. The investigation aimed to show two things, (a) that the size of objects, especially the height off ground is consistent within an environment, and (b) that based on this consistency, objects can be identified and their general size used to scale a model. To test the idea a hypothesis is first tested on a terrestrial lidar scan of an indoor environment. Later as a proof of concept the same test is applied to a model created using imagery. The most notable finding was that the detection of objects can be more readily done by studying the ratio between the dimensions of objects that have their dimensions defined by human physiology. For example the dimensions of desks and chairs are related to the height of an average person. In the test, the difference between generalised and actual dimensions of objects were assessed. A maximum difference of 3.96% (2.93<i>cm</i>) was observed from automated scaling. By analysing the ratio between the heights (distance from the floor) of the tops of objects in a room, identification was also achieved.

scholarly journals Comparative Study of Two Pose Measuring Systems Used to Reduce Robot Localization Error

Sensors ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 1305
Author(s):  
Marek Franaszek ◽  
Geraldine S. Cheok ◽  
Jeremy A. Marvel
Keyword(s):  
Rigid Body ◽  
Body Condition ◽  
Degrees Of Freedom ◽  
Industrial Robot ◽  
Substantial Reduction ◽  
Three Dimensional ◽  
Robot Localization ◽  
Localization Error ◽  
Measuring Systems ◽  
The Difference

The performance of marker-based, six degrees of freedom (6DOF) pose measuring systems is investigated. For instruments in this class, the pose is derived from locations of a few three-dimensional (3D) points. For such configurations to be used, the rigid-body condition—which requires that the distance between any two points must be fixed, regardless of orientation and position of the configuration—must be satisfied. This report introduces metrics that gauge the deviation from the rigid-body condition. The use of these metrics is demonstrated on the problem of reducing robot localization error in assembly applications. Experiments with two different systems used to reduce the localization error of the same industrial robot yielded two conflicting outcomes. The data acquired with one system led to substantial reduction in both position and orientation error of the robot, while the data acquired with a second system led to comparable reduction in the position error only. The difference is attributed to differences between metrics used to characterize the two systems.

A framework for the automatic annotation of car aesthetics

2007 ◽  
Vol 21 (1) ◽  
pp. 73-90 ◽  
Author(s):  
CHIARA E. CATALANO ◽  
FRANCA GIANNINI ◽  
MARINA MONTI ◽  
GIULIANA UCELLI
Keyword(s):  
Computational Models ◽  
Three Dimensional ◽  
Multimedia Data ◽  
Computer Assisted ◽  
Target Market ◽  
Automatic Annotation ◽  
Digital Models ◽  
Semantic Data ◽  
Three Dimensional Models ◽  
Definition Of

The design of a new car is guided by a set of directives indicating the target market, specific engineering, and aesthetic constraints, which may also include the preservation of the company brand identity or the restyling of products already on the market. When creating a new product, designers usually evaluate other existing products to find sources of inspiration or to possibly reuse successful solutions. In the perspective of an optimized styling workflow, great benefit could be derived from the possibility of easily retrieving the related documentation and existing digital models both from internal and external repositories. In fact, the rapid growth of resources on the Web and the widespread adoption of computer-assisted design tools have made available huge amounts of data, the utilization of which could be improved by using more selective retrieval methods. In particular, the retrieval of aesthetic elements may help designers to create digital models conforming to specific styling properties more efficiently. The aim of our research is the definition of a framework that supports (semi)automatic extraction of semantic data from three-dimensional models and other multimedia data to allow car designers to reuse knowledge and design solutions within the styling department. The first objective is then to capture and structure the explicit and implicit elements contributing to the definition of car aesthetics, which can be realistically tackled through computational models and methods. The second step is the definition of a system architecture that is able to transfer such semantic evaluation through the automatic annotation of car models.

scholarly journals AlphaFold-Predicted Structures of KCTD Proteins Unravel Previously Undetected Relationships among the Members of the Family

Biomolecules ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1862
Author(s):  
Luciana Esposito ◽  
Nicole Balasco ◽  
Giovanni Smaldone ◽  
Rita Berisio ◽  
Alessia Ruggiero ◽  
...  
Keyword(s):  
Structural Information ◽  
Three Dimensional ◽  
Structural Data ◽  
Protein Family ◽  
General Sequence ◽  
Btb Domain ◽  
The Family ◽  
Three Dimensional Models ◽  
Definition Of ◽  
Sequence Similarities

One of the most striking features of KCTD proteins is their involvement in apparently unrelated yet fundamental physio-pathological processes. Unfortunately, comprehensive structure–function relationships for this protein family have been hampered by the scarcity of the structural data available. This scenario is rapidly changing due to the release of the protein three-dimensional models predicted by AlphaFold (AF). Here, we exploited the structural information contained in the AF database to gain insights into the relationships among the members of the KCTD family with the aim of facilitating the definition of the structural and molecular basis of key roles that these proteins play in many biological processes. The most important finding that emerged from this investigation is the discovery that, in addition to the BTB domain, the vast majority of these proteins also share a structurally similar domain in the C-terminal region despite the absence of general sequence similarities detectable in this region. Using this domain as reference, we generated a novel and comprehensive structure-based pseudo-phylogenetic tree that unraveled previously undetected similarities among the protein family. In particular, we generated a new clustering of the KCTD proteins that will represent a solid ground for interpreting their many functions.

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