scholarly journals Quadrilateral mesh fitting that preserves sharp features based on multi-normals for Laplacian energy

2014 ◽  
Vol 1 (2) ◽  
pp. 88-95 ◽  
Author(s):  
Yusuke Imai ◽  
Hiroyuki Hiraoka ◽  
Hiroshi Kawaharada
Keyword(s):  
Energy Minimization ◽  
Computer Aided Design ◽  
Performance Testing ◽  
Target Surface ◽  
Hexahedral Mesh ◽  
Element Analysis ◽  
Laplacian Energy ◽  
Hexahedral Meshes ◽  
Normal Vectors ◽  
The Cost

Abstract Because the cost of performance testing using actual products is expensive, manufacturers use lower-cost computer-aided design simulations for this function. In this paper, we propose using hexahedral meshes, which are more accurate than tetrahedral meshes, for finite element analysis. We propose automatic hexahedral mesh generation with sharp features to precisely represent the corresponding features of a target shape. Our hexahedral mesh is generated using a voxel-based algorithm. In our previous works, we fit the surface of the voxels to the target surface using Laplacian energy minimization. We used normal vectors in the fitting to preserve sharp features. However, this method could not represent concave sharp features precisely. In this proposal, we improve our previous Laplacian energy minimization by adding a term that depends on multi-normal vectors instead of using normal vectors. Furthermore, we accentuate a convex/concave surface subset to represent concave sharp features.

Quadrilateral Meshing for Hexahedral Mesh Generation Based on Facet Normal Matching

2014 ◽  
Vol 8 (3) ◽  
pp. 356-364 ◽  
Author(s):  
Hiroshi Kawaharada ◽  
◽  
Yusuke Imai ◽  
Hiroyuki Hiraoka
Keyword(s):  
Mesh Generation ◽  
Energy Minimization ◽  
Computer Aided Design ◽  
Performance Testing ◽  
Normal Vector ◽  
Hexahedral Mesh ◽  
Element Analysis ◽  
Laplacian Energy ◽  
Hexahedral Mesh Generation ◽  
Normal Vectors

Because performance testing using actual products is costly, manufacturers use lower-cost Computer-Aided Design (CAD) simulations. In this paper, we focus on hexahedral meshes, which are more accurate than tetrahedral meshes, for finite element analysis. Our final objective is automatic hexahedral mesh generation with sharp features to precisely represent the corresponding features of a target shape. Our hexahedral mesh is generated using a voxel-based algorithm. In our previous works, we fitted the surface of the voxels to the target surface using Laplacian energy minimization and used normal vectors in the fitting to preserve sharp features. However, we were unable to precisely represent sharp concave features using the method. In this proposal, we improve the previously used Laplacian energy minimization by adding a term that depends on facet normalmatching for multi-normal vectors, instead of using normal vector matching.

Edge-Based Quadrilateral Mesh Fitting Using Normal Vector Diffusion

2015 ◽  
Vol 9 (6) ◽  
pp. 756-764
Author(s):  
Yusuke Imai ◽  
◽  
Seungki Kim ◽  
Hiroyuki Hiraoka ◽  
Hiroshi Kawaharada ◽  
...  
Keyword(s):  
Boundary Surface ◽  
Cnc Machining ◽  
Numerical Control ◽  
Normal Vector ◽  
Boundary Edge ◽  
Hexahedral Mesh ◽  
Target Shape ◽  
Laplacian Energy ◽  
Hexahedral Meshes ◽  
Normal Vectors

Nowadays, many manufacturers use computer-aided design (CAD) for processes such as computer numerical control (CNC) machining, simulations, and press working. They use CAD models for their simulations because the cost of performance simulations is lower than that of actual product testing. In this paper, we consider hexahedral meshes for finite element analysis because simulations using such meshes are more accurate than those using tetrahedral meshes. Our aim is to automatically generate hexahedral meshes with sharp features that precisely represent the corresponding features of the target shape. Our hexahedral mesh generation algorithm is voxel-based, and thus in our previous studies, we fitted the surface of voxels to the target surface using Laplacian energy minimization. We used normal vectors during the fitting to preserve any existing sharp features. Each face of the boundary surface of a hexahedral mesh is a quadrilateral face, which we consider to consist of four triangles. Herein, we assume that an edge of a quadrilateral surface has four normal vectors of four connected triangles. Here, we diffuse normal vectors of the target shape after extracting them to accurately preserve the shape features. Moreover, for the Laplacian energy, we add a term that matches the normal vector of the target shape with the four normal vectors of a boundary edge. Finally, we present some experimental results using our method.

Effect of infill and density pattern on the mechanical behaviour of ABS parts manufactured by FDM using Taguchi and ANOVA approach

2021 ◽  
Vol 111 (2) ◽  
pp. 66-77
Author(s):  
M. Othmani ◽  
K. Zarbane ◽  
A. Chouaf
Keyword(s):  
Tensile Strength ◽  
Computer Aided Design ◽  
Numerical Test ◽  
Acrylonitrile Butadiene Styrene ◽  
Tensile Behaviour ◽  
Element Analysis ◽  
Mechanical Tensile ◽  
Experimental Values ◽  
The Cost ◽  
Aided Design

Purpose: The present work aims to investigate the effect of many infill patterns (rectilinear, line, grid, triangles, cubic, concentric, honeycomb, 3D honeycomb) and the infill density on the mechanical tensile strength of an Acrylonitrile Butadiene Styrene (ABS) test specimen manufactured numerically by FDM. Design/methodology/approach: Computer-Aided Design (CAD) software has been used to model the geometry and the mesostructure of the test specimens in a fully automatic manner from a G-code file by using a script. Then, a Numerical Design of Experiments (NDoE) has been carried out by using Taguchi method and the Analysis of Variance (ANOVA). The tensile behaviour of these numerical test specimens has been studied by the Finite Element Analysis (FEA). Findings: The FEA results showed that a maximal Ultimate Tensile Strength (UTS) was reached by using the ‘concentric’ infill pattern combined with an infill density of 30%. The results also show that the infill pattern and the infill density are significant factors. Research limitations/implications: The low infill densities of 20% and 30% that have already been used in many previous studies, we have also applied it in order to reduce the time of the simulations. Indeed, with high infill density, the simulations take a very excessive time. In an ongoing study, we predicted higher percentages. Practical implications: This study provided an important modelling tool for the design and manufacture of functional parts and helps the FDM practitioners and engineers to manufacture strong and lightweight FDM parts by choosing the optimal process parameters. Originality/value: This study elucidated the effect of various infill patterns on the tensile properties of the test specimens and applied for the first time a NDoE using numerical test specimens created by the mesostructured approach, which considerably minimized the cost of the experiments while obtaining an error of 6.8% between the numerical and the experimental values of the UTS.

A Face Clustering Method for a Hexahedral Meshing

2003 ◽  
Author(s):  
Jun Doi ◽  
Atsushi Yamada ◽  
Keisuke Inoue
Keyword(s):  
Manufacturing Industry ◽  
Dimensional Space ◽  
Difficult Problem ◽  
Hexahedral Mesh ◽  
Element Analysis ◽  
Intermediate Model ◽  
3 Dimensional ◽  
Face Clustering ◽  
Hexahedral Meshes

Finite element analysis has become a key technology for a design process of manufacturing industry. A hexahedral mesh is focused, because using a hexahedral mesh increases the quality of analysis. However it is very difficult problem to generate high quality hexahedral meshes, and there are many challenging research topics. Our goal is to develop a method to generate hexahedral meshes automatically to general volumes. Our method uses an intermediate model to recognize the input volume. The intermediate model is defined in the integer 3-dimensional space, and faces of the intermediate model are vertical to coordinate axes. Hexahedral mesh is generated by dividing the intermediate model into integer grids, and blocks of grids are projected into original volume. In this paper, we describe the method to generate a topology of the intermediate model. We use face clustering technique to generate the topology of the intermediate model. The faces of the input volume are clustered into 6 types; according to 3 coordinate axes and its direction, and clustered faces will be the faces of the intermediate model.

CAD Of Anticorrosive Protection Of Steel Structures

2019 ◽  
pp. 18-23
Keyword(s):  
Protective Coating ◽  
Computer Aided Design ◽  
Steel Structures ◽  
Cost Effective ◽  
Operating Conditions ◽  
Computational Tool ◽  
Protection Method ◽  
Cost Effective Method ◽  
The Cost ◽  
Aided Design

The choice of cost-effective method of anticorrosive protection of steel structures is an urgent and time consuming task, considering the significant number of protection ways, differing from each other in the complex of technological, physical, chemical and economic characteristics. To reduce the complexity of solving this problem, the author proposes a computational tool that can be considered as a subsystem of computer-aided design and used at the stage of variant and detailed design of steel structures. As a criterion of the effectiveness of the anti-corrosion protection method, the cost of the protective coating during the service life is accepted. The analysis of existing methods of steel protection against corrosion is performed, the possibility of their use for the protection of the most common steel structures is established, as well as the estimated period of effective operation of the coating. The developed computational tool makes it possible to choose the best method of protection of steel structures against corrosion, taking into account the operating conditions of the protected structure and the possibility of using a protective coating.

scholarly journals Performance Testing and Strength Prediction of Ceramic-to-Metal Joints

1993 ◽  
Author(s):  
J. H. Selverian ◽  
Dave A. ONeil ◽  
Shinhoo Kang
Keyword(s):  
Room Temperature ◽  
Performance Testing ◽  
Strength Prediction ◽  
High Temperature Strength ◽  
Torsional Loading ◽  
Element Analysis ◽  
Failure Theory ◽  
Brazed Joints ◽  
Temperature Shear ◽  
Shrink Fit

Brazed joints were made between silicon nitride and Ni-based and Fe-based super alloys. Room temperature shear (torsion) strengths ranged from 75–242 MPa for Si3N4-to-Incoloy 909 joints and from 30–127 MPa for the Si3N4-to-Inconel 718 joints. At 500 °C the joint strength was 120 MPa while at 650°C and 950°C the joints strengths were less than 20 MPa. These low strengths at 650°C and 950°C were attributed to a reduction in the shrink-fit and to low braze strength at these high temperatures. Finite element analysis (FEA) and a probabilistic failure theory (CARES) were used to predict the joint strengths. The predicted joint strengths agreed well with measured joint strengths in torsional loading at 20°C. Torsion tests were also performed at 650°C. Aspects of the material systems, residual stresses, mechanical behavior, and strength predictions are presented. Two new braze alloys based on the Au-Ni-Cr-Fe system were used to overcome the poor high temperature strength. Joints made with these brazes had good strength (85 MPa and 35 N-m) at 650°C.

The Rod Force Law Analysis of 600MW Air Cooling Tower

2014 ◽  
Vol 945-949 ◽  
pp. 1135-1138
Author(s):  
Tao Liang ◽  
Chun Ling Meng ◽  
Yang Li ◽  
Xiu Hua Zhao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Axial Force ◽  
Optimization Design ◽  
Cooling Tower ◽  
Air Cooling ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
The Cost

The finite element analysis of large air cooling tower was carried out using ABAQUS. On the basis of strength above,8 types of the axial force are analyzed and summarized, find valuable rules, and put forward the further optimization design. So that it can satisfy the strength and stability of air cooling tower, the structure is more reasonable, reduce weight, reduce the cost.

Standardized Foundations Database for Combat Systems

2014 ◽  
Author(s):  
M. Harbison ◽  
W. Koon ◽  
V. Smith ◽  
P. Haymon ◽  
D. Niole ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cost Savings ◽  
Ship Design ◽  
Separate Analysis ◽  
Element Analysis ◽  
Weapon Systems ◽  
System Requirements ◽  
Design Requirements ◽  
The Cost

As a result of enhanced performance and mission requirements for Navy ships, ship design has dramatically increased the use of higher strength, lightweight steels and various local reinforcements, e.g., deck inserts, ring stiffeners, etc., in foundation designs to satisfy the design requirements for supporting machinery, consoles, and weapon systems among others. In additional to operational loading requirements, most of these foundations must also be designed to satisfy shock, vibration and other combat system requirements. While the same piece of equipment may be used in other ship contracts, the foundations are uniquely designed and require a separate analysis and drawing package. Computer modeling and Finite Element Analysis (FEA) have helped reduce the labor required to analyze foundations, but the high number of “unique” foundations as well as changes which necessitate a new analysis still create a large workload for engineers. This is further compounded by increased costs in production due to greater numbers of unique parts and materials that must be marked, stored, and retrieved later for fabrication. This goal of this project was to determine the cost-savings potential of leveraging past foundations work in designing, analyzing, and drawing foundations in the future. By the project’s conclusion Ingalls will have created a database for rapid access to previously-generated foundation information, the framework of which will be publicly available for all shipyards to populate with their own foundation information.

Computer-Aided Gear Product Realization

2018 ◽  
Author(s):  
Alireza Yazdanshenas ◽  
Emilli Morrison ◽  
Chung-Hyun Goh ◽  
Janet K. Allen ◽  
Farrokh Mistree
Keyword(s):  
Computer Aided Design ◽  
Interaction Analysis ◽  
Gear Tooth ◽  
Integrated Design ◽  
System Level ◽  
Trial And Error ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Gear Design ◽  
Computer Aided

To save time and resources, many are making the transition to developing their ideas virtually. Computer-aided gear production realization is becoming more and more desired in the industry. To produce gears with custom qualities, such as material, weight and shape, the trial and error approach has yielded the best results. However, trial and error is costly and time consuming. The computer-aided integrated design and manufacturing approach is intended to resolve these drawbacks. A simple one stage reduction spur gearbox is used as an example in a case study. First, the gear geometry is developed using computer aided design (CAD) modeling. Next, using MATLAB/Simulink, the gear assembly is connected virtually to other subsystems for system expectations and interaction analysis. Finally, using finite element analysis (FEA) tools such as ABAQUS, a dynamic FEA of the gear integration is completed to analyze the stress concentrations and gear tooth failures. Through this method of virtual gear design, customized dimensions and specifications of gears for satisfying system-level requirements can be developed, thereby saving time and manufacturing costs for any custom gear design request.

scholarly journals RESEARCH OF CLOUDY TECHNOLOGIES AS А SERVICES

2020 ◽  
Vol 3 (7) ◽  
pp. 43-62
Author(s):  
Tetyana Smirnova ◽  
Liudmyla Polishchuk ◽  
Oleksii Smirnov ◽  
Kostiantyn Buravchenko ◽  
Andrii Makevnin
Keyword(s):  
Computer Aided Design ◽  
Service Providers ◽  
Cloud Service ◽  
Computer Engineering ◽  
Durability Design ◽  
Physical Prototype ◽  
Extended Analysis ◽  
Basic Services ◽  
The Cost ◽  
Cloud Technologies

In order to determine the basic conditions for further research to identify threats to cloud technologies and measures for their counteraction, the article provides an extended analysis of cloud computing as a service. Among the above services, the basic services IaaS, SaaS, PaaS are selected, which are the basis for the existence of more unified services (CaaS, MCaS, DaaS, FaaS, IPaaS, MBaaS, NaaS, SeCaa, DBaaS, MaaS, DBaaS, MaaS, DBaaS, MaaS that increase the scope. Listed are possible service providers, including Ukrainian. It is determined that in order to transfer the work of systems of engineering calculations and computer-aided design (CAD) systems to a cloud platform, a rather new promising service CAEaaS (Cоmputеr Аidеd Еnginееrіng аs а Sеrvіcе) – computer engineering systems as a service. The most popular SAEs are used in the following industries: mechanical engineering and machine tools, defense and aerospace, energy, shipbuilding, semiconductor production, telecommunications, chemical, pharmaceutical and medical industry, construction, production of heating, air conditioning, ventilation. The success of a project decision depends on the awareness of responsible choice in the very first stage. Unfortunately, in support of the CAEaaS cloud service, Ukraine is only making the first steps and can provide the technological needs of enterprises, provided the involvement of foreign suppliers. According to the authors of the article, the future of the Ukrainian industry according to the cloud service SAEaS. Because CAE helps reduce the cost and time of product development, improve product quality and durability. Design decisions can be made based on their impact on performance. Designs can be evaluated and refined using computer modeling rather than physical prototype testing, saving money and time. This article is the basis for further research on the identification of threats to cloud technologies and their response.

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