scholarly journals Filling Simple Holes of Triangular Mesh by using Enhanced Advancing Front Mesh (EAFM) method

2018 ◽  
Vol 7 (2.15) ◽  
pp. 81
Author(s):  
Noorehan Awang ◽  
Rahmita Wirza Rahmat ◽  
Puteri Suhaiza Sulaiman ◽  
Azmi Jaafar ◽  
Ng Seng Beng
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Test Data ◽  
3D Models ◽  
Triangular Mesh ◽  
Triangular Meshes ◽  
Element Analysis ◽  
Advancing Front ◽  
Data Function

Triangular meshes are extensively used to represent 3D models. Some surfaces cannot be digitised due to various reasons such as inadequacy of the scanner, and this generally occurs for glossy, hollow surfaces and dark-coloured surfaces. This cause triangular meshes to contain holes and it becomes difficult for numerous successive operations such as model prototyping, model rebuilding, and finite element analysis. Hence, it is necessary to fill these holes in a practical manner. In this paper, the Enhanced Advancing Front Mesh (EAFM) method was introduced for recovering missing simple holes in an object. The first step in this research was to extract the feature vertices around a hole on a 3D test data function. Then the Advancing Front Mesh (AFM) method was used to fill the holes. When conflicts occurred during construction of the triangle, the EAFM method was introduced to enhance the method. The results of the study show that the enhanced method is simple, efficient and suitable for dealing with simple hole problems.  

Influence of Construction Procedures on the Liner and Stress of a PC Continuous Beam Bridge

2010 ◽  
Vol 121-122 ◽  
pp. 162-167
Author(s):  
Hu Cheng ◽  
Guo Xuan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Test Data ◽  
Significant Influence ◽  
Continuous Beam ◽  
Element Analysis ◽  
Continuous Beam Bridge ◽  
Cantilever Construction ◽  
Beam Bridge

During the construction of a bridge, the construction procedures may change from the originally designed procedures due to some reasons like the weather. In this paper, the influence of construction procedures on the liner and stress is investigated for a prestressed continuous beam bridge with three spans. Finite element analysis indicated that construction procedures have great impact on the liner control and they affect the middle span and side span differently. Although different sets of construction procedures cause different stress at corresponding construction stages after the cantilever construction is finished, they have no significant influence on the stress of the finally built bridge. Test data agreed with finite element analysis. It is thus the influence of construction procedures on bridge liner control should not be neglected.

scholarly journals Evaluation of U10Mo Fuel Plate Irradiation Behavior via Numerical and Experimental Benchmarking

2012 ◽  
Author(s):  
Samuel J. Miller ◽  
Hakan Ozaltun
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
3D Models ◽  
Creep Model ◽  
Element Analysis ◽  
Dimensional Changes ◽  
3 Dimensional ◽  
Out Of Plane ◽  
2D And 3D ◽  
Irradiation Behavior

This article analyzes dimensional changes due to irradiation of monolithic plate-type nuclear fuel and compares results with finite element analysis of the plates during fabrication and irradiation. Monolithic fuel plates tested in the Advanced Test Reactor (ATR) at Idaho National Lab (INL) are being used to benchmark the performance of proposed fuel for several high power research reactors. Post-irradiation metallographic images of plates sectioned at the mid-plane were analyzed to determine dimensional changes of the fuel and the cladding response. A constitutive model of the fabrication process and irradiation behavior of the tested plates was developed using the general purpose commercial finite element analysis package, ABAQUS. Using calculated burn-up profiles of irradiated plates to model the power distribution and including irradiation behaviors such as swelling and irradiation enhanced creep, model simulations allow analysis of plate parameters that are either impossible or infeasible in an experimental setting. The development and progression of fabrication induced stress concentrations at the plate edges was of primary interest, as these locations have a unique stress profile during irradiation. Additionally, comparison between 2D and 3D models was performed to optimize analysis methodology. In particular, the ability of 2D and 3D models to account for out of plane stresses which result in 3-dimensional creep behavior that is a product of these components. Results show that assumptions made in 2D models for the out-of-plane stresses and strains cannot capture the 3-dimensional physics accurately and thus 2D approximations are not representative. Stress-strain fields are dependent on plate geometry and irradiation conditions, thus, if stress based criteria is used to predict plate behavior (as opposed to material impurities, fine micro-structural defects, or sharp power gradients), unique 3D finite element formulation for each plate is required.

Finite Element Analysis of Ship Lock Chamber Structure

2014 ◽  
Vol 1065-1069 ◽  
pp. 597-600
Author(s):  
Chao Sun ◽  
Zi Chang Shang Guan ◽  
Xiao Xuan Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Modeling ◽  
Base Plate ◽  
3D Models ◽  
Element Analysis ◽  
Calculation Process ◽  
Lock Chamber ◽  
Set Up ◽  
Ship Lock

While considering various structural and material requirements, 3D models of ship chambers in the ship lock structure using finite element modeling (FEM) software ANSYS. By using FEM software to set up the contacting sections between the base plate, refilled soils and foundation, analyses were done to caluculate the forces exerted on the structure of the ship chamber. After checking the reasonability of the calculated results, discussions were made on the calculation process to allow for future empirical calculations.

scholarly journals Sealing Mechanics Study of Laryngeal Mask Airways via 3D Modeling and Finite Element Analysis

2021 ◽  
Author(s):  
Hongxia Liao ◽  
Liqiang Chen ◽  
Junfeng Chen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cuff Pressure ◽  
3D Models ◽  
Laryngeal Mask ◽  
Comprehensive Understanding ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Sealing Mechanism ◽  
Mucosal Pressure

Abstract Background: Proper sealing of laryngeal mask airways (LMAs) is critical for airway management in clinical use. A good understanding of the LMA sealing mechanism provides a scientific foundation to improve the sealing of LMAs to reduce the incidence of adverse events. However, no existing methods provide a systematic study on the LMA sealing mechanics. Methods: Computer-aided 3D models are established to visualize LMA – pharynx interactions directly. The finite element analysis (FEA) is adopted to study the LMA sealing mechanics. Results: Two case studies are provided in the paper. The LMA is loaded with a low cuff pressure (CP) (9 mmHg) to investigate the cause of leaking in Case I, and with a high CP (45 mmHg) to detect the critical points of high mucosal pressure in Case II. The established 3D models provide initiative visualization of the sealing situations. The visualization results are verified by pressure distribution along the contacting surface generated from FEA as the quantitative study. Conclusions: Compared with the existing methods, the proposed method does not introduce additional cost, and can provide globe monitoring on the LMA and a comprehensive understanding of sealing mechanics in all areas. The findings on the sealing mechanism and corresponding suggestions for clinic use of LMAs and LMA design have also been presented in the paper.

Development of a New, Correlated FEA Method of Assessing Mooring Chain Fatigue

2019 ◽  
Author(s):  
Gary H. Farrow ◽  
Andrew E. Potts ◽  
Andrew A. Kilner ◽  
Phillip P. Kurts ◽  
Simon Dimopoulos ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Fatigue Test ◽  
Test Data ◽  
Linear Chain ◽  
Element Analysis ◽  
Chain Link ◽  
Non Linear ◽  
Mooring Chain

Abstract The first phase of the Chain FEARS (Finite Element Analysis of Residual Strength) Joint Industry Project (JIP) aimed to develop guidance for the determination of a rational discard criteria for mooring chains subject to severe pitting corrosion which, based on current code requirements, would otherwise require immediate removal and replacement. Critical to the ability to evaluate the residual fatigue life of a degraded chain, is to have an accurate estimate of the chain in its as-new condition, thereby providing a benchmark for any loss in fatigue life associated with severe corrosion or wear. A large collection of fatigue test data was collated for comparison and to establish underlying trends in as-new mooring chain fatigue response. A non-linear multi-axial Finite Element Analysis (FEA) fatigue assessment method was developed to correlate against available as-new chain link fatigue test data and underlying failure trends as part of the JIP achieving this critical requirement. It was established that the linear FEA fatigue method currently employed in the industry is too simplistic and does not correlate with the fatigue test data, whereas an alternative method of assessing fatigue based on FEA, developed with respect to the DNV B1 material curve, correlates well with the available physical fatigue test data. The FEA method uses a non-linear chain link FEA and multi-axial stress fatigue calculation method to determine an equivalent Stress Magnification Factor (SMF). This method achieves good correlation of predicted utilisations and associated cycles-to-failure with fatigue test data and in respect of critical locations with evidenced failure locations. The method of equivalent SMF calculation accounted for the significant effects on fatigue performance including proof load induced residual stress, mean stress levels and the increase in material fatigue endurance associated with increased steel UTS (i.e. increased offshore mooring chain grade). The analytical method developed in this study achieved a high degree of correlation with as-new chain fatigue test data, and should enable the accurate prediction of fatigue stresses around a link and in particular for irregular geometry associated with corrosion degraded chain links.

Stress Analysis in Ceramic Inlays Restored Premolars

2012 ◽  
Vol 503-504 ◽  
pp. 363-366
Author(s):  
Liliana Sandu ◽  
Florin Topală ◽  
Sorin Porojan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Computational Simulation ◽  
3D Models ◽  
Composite Resins ◽  
Element Analysis ◽  
Mesh Structure ◽  
Ceramic Inlays ◽  
Optimal Shapes ◽  
Preparation Design

Ceramic inlays can be used on premolars requiring a MOD restoration instead posterior composite resins direct restorations and offer a durable alternative. Because it is known that MOD inlays may increase the susceptibility to fracture, it is important to ensure optimal performance in selection of the adequate preparation design to reduce stresses in teeth structures and also in the restorations. The aim of the study was to determine, using finite element analysis, the optimal shapes of ceramics MOD inlays in premolars in order to minimize the potentially damaging effects of stress on teeth structures and restorations. The study was performed on an upper first premolar, using a finite element analysis. 3D models of maxillary first premolars, prepared for MOD inlays with different tapers were generated. The mesh structure of the solid 3D model was created using the computational simulation of Ansys finite element analysis software. An occlusal load of 200 N was conducted, and stresses occurring in the ceramic inlays, and teeth structures were calculated. The study provides a biomechanical explanation for inlays restored teeth. MOD inlays transfer functional stress to the teeth structures. The taper of the preparations had no significant influence on the stress values for all the studied cases.

scholarly journals FROM SURVEY TO FEM ANALYSIS FOR DOCUMENTATION OF BUILT HERITAGE: THE CASE STUDY OF VILLA REVEDIN-BOLASCO

2017 ◽  
Vol XLII-5/W1 ◽  
pp. 527-533 ◽  
Author(s):  
A. Guarnieri ◽  
F. Fissore ◽  
A. Masiero ◽  
A. Di Donna ◽  
U. Coppa ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Analysis ◽  
Laser Scanning ◽  
Fem Analysis ◽  
3D Models ◽  
Element Analysis ◽  
Historical Building ◽  
Built Heritage ◽  
Gnss Measurements

In the last decade advances in the fields of close-range photogrammetry, terrestrial laser scanning (TLS) and computer vision (CV) have enabled to collect different kind of information about a Cultural Heritage objects and to carry out highly accurate 3D models. Additionally, the integration between laser scanning technology and Finite Element Analysis (FEA) is gaining particular interest in recent years for structural analysis of built heritage, since the increasing computational capabilities allow to manipulate large datasets. In this note we illustrate the approach adopted for surveying, 3D modeling and structural analysis of Villa Revedin-Bolasco, a magnificent historical building located in the small walled town of Castelfranco Veneto, in northern Italy. In 2012 CIRGEO was charged by the University of Padova to carry out a survey of the Villa and Park, as preliminary step for subsequent restoration works. The inner geometry of the Villa was captured with two Leica Disto D3a BT hand-held laser meters, while the outer walls of the building were surveyed with a Leica C10 and a Faro Focus 3D 120 terrestrial laser scanners. Ancillary GNSS measurements were also collected for 3D laser model georeferencing. A solid model was then generated from the laser global point cloud in Rhinoceros software, and portion of it was used for simulation in a Finite Element Analysis (FEA). In the paper we discuss in detail all the steps and challenges addressed and solutions adopted concerning the survey, solid modeling and FEA from laser scanning data of the historical complex of Villa Revedin-Bolasco.

scholarly journals A Finite Element Modeling and Simulation of Human Temporomandibular Joint with and Without TM Disorders: An Indian Experience

2021 ◽  
Vol 8 (3) ◽  
pp. 347-355
Author(s):  
Mehak Sharma ◽  
Manoj Soni
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Temporomandibular Joint ◽  
Computational Study ◽  
3D Models ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Stress Studies ◽  
Jaw Joint ◽  
Von Mises

Temporomandibular joint (TMJ) is anatomically the most intricate joint which connects the lower jaw to the upper jaw and regulates jaw movements. It significantly deals with mastication and speech. It is hence imperative to study the mechanics and functioning of the jaw joint to devise alternative solutions for its replacement whenever required. Further, human skulls are anthropologically categorized into three types – African, Asian and European. Out of these, the Indian skull is also a bit different than its Asian counterparts because of its osteology and skeletal biology. Hence, a comprehensive biomechanical and computational study is essential to provide customized solutions. For the present study, four different loading conditions are selected to perform finite element analysis on the human skull, Anonymized and unidentifiable CT scan data sets from open-source web platforms are converted to STL and then 3D models using 3D slicer. Finite element analysis of jaw joint is carried out. Results based on Von Mises stress studies show significant behavioral differences under varying load conditions. Hence, it is crucial to identify solutions for TMJ disorders of the Indian population.

Investigations Into Fatigue Performance of Offshore Mooring Chains

2017 ◽  
Author(s):  
Gary H. Farrow ◽  
Andrew E. Potts ◽  
Daniel G. Washington
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Fatigue Test ◽  
Test Data ◽  
Assessment Method ◽  
Accurate Estimate ◽  
Element Analysis ◽  
Factors Influencing ◽  
Non Linear

The Chain Finite Element Analysis of Residual Strength Joint Industry Project (Chain FEARS JIP) aimed to develop guidance for the determination of a rational discard criteria for mooring chains subject to severe pitting corrosion which would otherwise require immediate removal and replacement. Critical to the ability to evaluate the residual fatigue life of a degraded chain, is to have an accurate estimate of the chain in its as-new condition, thereby providing a benchmark for any loss in fatigue life associated with severe corrosion or wear. A non-linear multi-axial Finite Element Analysis (FEA) fatigue assessment method was developed and correlated against available fatigue test data as part of the JIP achieving this critical requirement. The development of this correlated methodology necessitated a review of: • The available mooring chain fatigue test data, to identify the factors influencing chain fatigue life and failure location. • FEA fatigue methodologies currently employed in the industry. • Current Class Rules relating to fatigue estimation. • The influence of material, manufacturing and operational factors on chain fatigue life. It was established that while the linear FEA fatigue method currently employed in the industry does not correlate with the fatigue test data, the non-linear multi-axial FEA fatigue method developed in the JIP afforded good correlation with test data. It was also demonstrated that the magnitude of mean chain tension and inconsistency in proof loading, as a consequence of the inconsistency in Class Minimum Break Load (MBL) specification, and with respect to chain size and the varying material ductility of steel grades, effects fatigue life. The identified inconsistency in the proofing indicates a likely inconsistency in conservatism embodied in the Class Rules fatigue formulation. Consequently it is possible that chains of certain size and grade may have significantly less fatigue life than anticipated by Class. Further work is recommended to establish a more rational proof load specification and to develop an alternative Class Rules fatigue formulation accounting for the identified factors influencing fatigue.

Short single-wedge stems have higher risk of periprosthetic fracture than other cementless stem designs in Dorr type A femurs: a finite element analysis

2020 ◽  
pp. 112070002094918
Author(s):  
Sumon Nandi ◽  
Anoli Shah ◽  
Amin Joukar ◽  
Kevin Becker ◽  
Cody Crutchfield ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Standard Length ◽  
Periprosthetic Fracture ◽  
Type A ◽  
3D Models ◽  
Cementless Stem ◽  
Element Analysis ◽  
Stem Design ◽  
Single Leg Stance

Background: The use of total hip arthroplasty (THA) femoral stems that transmit force in a favourable manner to the femur may minimise periprosthetic fractures. Finite element analysis (FEA) is a computerised method that analyses the effect of forces applied to a structure with complex shape. Our aim was to apply FEA to compare primary THA cementless stem designs and their association with periprosthetic fracture risk. Methods: 3-dimensional (3D) models of a Dorr Type A femur and 5 commonly used primary THA cementless stem designs (short single wedge, standard-length single wedge, modular, double-wedge metaphyseal filling, and cylindrical fully coated) were developed using computed tomography (CT) imaging. Implant insertion, single-leg stance, and twisting with a planted foot were simulated. FEA was performed, and maximum femoral strain along the implant-bone interface recorded. Results: Femoral strain was highest with short single-wedge stem design (0.3850) and lowest with standard-length single-wedge design (0.0520). Location of maximum femoral strain varied by stem design, but not with implant insertion, single-leg stance, or twisting with a planted foot. Strain was as high during implant insertion as with single-leg stance or twisting with a planted foot. Conclusions: Our results suggest the risk of intraoperative and postoperative periprosthetic fracture with THA in a Dorr A femur is highest with short single-wedge stems and lowest with standard-length single-wedge stems. Consideration may be given to minimising the use of short single-wedge stems in THA. Implant-specific sites of highest strain should be carefully inspected for fracture.

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