Comparative two- and three-dimensional finite element modelling techniques for tibial fractures

2001 ◽  
Vol 215 (2) ◽  
pp. 255-258 ◽  
Author(s):  
S Mishra ◽  
T N Gardner
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Stress And Strain ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Principal Stresses ◽  
Two Dimensional Model ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Often the choice of a two-dimensional modelling approach over a three-dimensional approach is made on the basis of available resources, and not on task appropriateness. In the case of simulating the mechanical behaviour of irregular anatomical structures in biomedical engineering, the authenticity of two-dimensional model behaviour and the interpretation of model solutions is of particular concern since little comparable two-dimensional and three-dimensional data have been published. As part of a research programme, a comparison was made between two-dimensional and three-dimensional finite element models (FEMs) that examine the stress-strain environment of a clinical bone fracture and callus. In comparison with the three-dimensional model, the two-dimensional model substantially underestimated peak compressive principal stresses in the callus tissue and peak equivalent strains. This was a consequence of geometrical and structural asymmetry in a plane perpendicular to the two-dimensional model. However, the two-dimensional model predicted similar patterns of stress and strain distribution to the corresponding mid-longitudinal plane of the three-dimensional model, and underestimates of peak stress and strain were much reduced. This confirmed that despite the irregular geometry and structure of the subject, the two-dimensional model provided a valid mechanical simulation in the plane of the fracture that it represented.

scholarly journals FEM analysis of a new miniplate: stress distribution on the plate, screws and the bone

2012 ◽  
Vol 06 (01) ◽  
pp. 009-015 ◽  
Author(s):  
Didem Nalbantgil ◽  
Murat Tozlu ◽  
Fulya Ozdemir ◽  
Mehmet Oguz Oztoprak ◽  
Tulin Arun
Keyword(s):  
Finite Element ◽  
Cortical Bone ◽  
Three Dimensional ◽  
Fem Analysis ◽  
Force Distribution ◽  
Bone Surface ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

ABSTRACTObjectives: Non-homogeneous force distribution along the miniplates and the screws is an unsolved question for skeletal anchorage in orthodontics. To overcome this issue, a miniplate structure was designed featuring spikes placed on the surface facing the cortical bone. The aim of this study was to examine and compare the force distribution of the newly designed plate-screw systems with the conventional one.Methods: A model of bone surface with 1.5 mm cortical thickness, along with the two newly designed miniplates and a standard miniplate-screw were simulated on the three-dimensional model. 200 g experimental force was applied to the tip of the miniplates and the consequential effects on the screws and cortical bone was evaluated using three-dimensional finite element method.Results: As a result of this finite element study, remarkably lower stresses were observed on the screws and the cortical bone around the screws with the newly designed miniplate when compared with the conventional one.Conclusion: The newly designed miniplate that has spikes was found effective in reducing the stress on and around the screws and the force was distributed more equivalently. (Eur J Dent 2012;6:9-15)

Two-dimensional and three-dimensional finite element models of external thread rolling

2002 ◽  
Vol 216 (4) ◽  
pp. 507-517 ◽  
Author(s):  
J P Domblesky ◽  
F Feng
Keyword(s):  
Three Dimensional ◽  
Finite Element Models ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Dimensional Finite Element ◽  
Thread Rolling ◽  
Three Dimensional Finite Element ◽  
Strain Model ◽  
Plane Strain Model

In the present study, the DEFORM computer code was used to develop two-dimensional and three-dimensional finite element models for simulating external thread rolling. To simulate rolling in two dimensions, a plane strain model was used where the thread is assumed to form through progressive penetration of the blank surface using a parallel set of wedge-shaped indenters. To develop the three-dimensional model, a flat-die rolling process was simulated which incorporated blank rotation, die movement and pitch angle on the die faces. Based on a comparison of thread form and microhardness with as-rolled threads, the plane strain model was found to provide a reasonable approximation of thread-rolling behaviour. Results obtained from the initial pass of the three-dimensional model are promising although progress is currently limited by the excessive computational time needed, frequency of remeshing and sliding at the die-blank interface.

Inclusion of Local Shell Behavior of Tubes Into a Two-Dimensional Beam Approximation of Deformation in Nuclear Fuel Channels

2002 ◽  
Author(s):  
S. Khajehpour ◽  
R. G. Sauve´ ◽  
N. Badie
Keyword(s):  
Finite Element ◽  
Contact Stiffness ◽  
Three Dimensional ◽  
Local Deformation ◽  
Beam Model ◽  
Two Dimensional ◽  
Dimensional Modeling ◽  
Dimensional Finite Element ◽  
Nonlinear Force ◽  
Three Dimensional Finite Element

A method has been developed to incorporate the local three-dimensional shell behavior of two concentric tubes in the two-dimensional beam modeling of the problem. The two dimensional modeling of fuel channels in CANDU pressurized heavy water nuclear reactors is used in lieu of a more accurate three dimensional finite element approach in order to reduce the on-line simulation time which greatly affects the SLAR (Spacer Location And Repositioning) maintenance operation cost during outage. However, effort must be made to include the three-dimensional shell behavior of these channels into the two-dimensional modeling. In recent studies a nonlinear force-dependent model for contact stiffness between the calandria tube and pressure tube has been developed. However, local deformation of calandria the tube at spacer locations due to in-reactor creep leads to settling of the spacer into the calandria tube that consequently reduces the gap between the two tubes. In this work, the effect of local deformation (elastic and creep) of calandria tubes on modeling of contact at spacer locations is assessed using a three dimensional finite element code. The result is incorporated into a two-dimensional beam model of the problem as a reduction in size of the spacers that separate the two tubes. It is shown that the proposed method increases the accuracy of prediction of contact time and the spacer. In general, the method described in this paper suggests a way to incorporate local shell deformation into beam models of slender shell structure.

Preliminary Ship Design Using One and Two-Dimensional Models

1999 ◽  
Vol 36 (02) ◽  
pp. 102-112
Author(s):  
Michael D. A. Mackney ◽  
Carl T. F. Ross
Keyword(s):  
Finite Element ◽  
Dimensional Analysis ◽  
Three Dimensional ◽  
Two Dimensional ◽  
One Dimensional ◽  
Dimensional Finite Element ◽  
Dimensional Models ◽  
Support Conditions ◽  
The One ◽  
Three Dimensional Finite Element

Computational studies of hull-superstructure interaction were carried out using one-, two-and three-dimensional finite element analyses. Simplification of the original three-dimensional cases to one- and two-dimensional ones was undertaken to reduce the data preparation and computer solution times in an extensive parametric study. Both the one- and two-dimensional models were evaluated from numerical and experimental studies of the three-dimensional arrangements of hull and superstructure. One-dimensional analysis used a simple beam finite element with appropriately changed sections properties at stations where superstructures existed. Two-dimensional analysis used a four node, first order quadrilateral, isoparametric plane elasticity finite element, with a corresponding increase in the grid domain where the superstructure existed. Changes in the thickness property reflected deck stiffness. This model was essentially a multi-flanged beam with the shear webs representing the hull and superstructure sides, and the flanges representing the decks One-dimensional models consistently and uniformly underestimated the three-dimensional behaviour, but were fast to create and run. Two-dimensional models were also consistent in their assessment, and considerably closer in predicting the actual behaviours. These models took longer to create than the one-dimensional, but ran in very much less time than the refined three-dimensional finite element models Parametric insights were accomplished quickly and effectively with the simplest model and processor, but two-dimensional analyses achieved closer absolute measure of the displacement behaviours. Although only static analysis with simple loading and support conditions were presented, it is believed that similar benefits would be found for other loadings and support conditions. Other engineering components and structures may benefit from similarly judged simplification using one- and two-dimensional models to reduce the time and cost of preliminary design.

scholarly journals Three-Dimensional Response of the Supported-Deep Excavation System: Case Study of a Large Scale Underground Metro Station

Geosciences ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 76
Author(s):  
Ashraf Hefny ◽  
Mohamed Ezzat Al-Atroush ◽  
Mai Abualkhair ◽  
Mariam Juma Alnuaimi
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Large Scale ◽  
Three Dimensional ◽  
Element Model ◽  
Two Dimensional ◽  
Deep Excavation ◽  
Metro Station ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The complexities and the economic computational infeasibility associated in some cases, with three-dimensional finite element models, has imposed a motive for many investigators to accept numerical modeling simplification solutions such as assuming two-dimensional (2D) plane strain conditions in simulation of several supported-deep excavation problems, especially for cases with a relatively high aspect ratio in plan dimensions. In this research, a two-dimensional finite element model was established to simulate the behavior of the supporting system of a large-scale deep excavation utilized in the construction of an underground metro station Rod El Farrag project (Egypt). The essential geotechnical engineering properties of soil layers were calculated using results of in-situ and laboratory tests and empirical correlations with SPT-N values. On the other hand, a three-dimensional finite element model was established with the same parameters adopted in the two-dimensional model. Sufficient sensitivity numerical analyses were performed to make the three-dimensional finite element model economically feasible. Results of the two-dimensional model were compared with those obtained from the field measurements and the three-dimensional numerical model. The comparison results showed that 3D high stiffening at the primary walls’ corners and also at the locations of cross walls has a significant effect on both the lateral wall deformations and the neighboring soil vertical settlement.

A comparative study between zirconia and titanium abutments on the stress distribution in parafunctional loading: A 3D finite element analysis

2020 ◽  
Vol 28 (6) ◽  
pp. 603-613 ◽  
Author(s):  
Efe Can Sivrikaya ◽  
Mehmet Sami Guler ◽  
Muhammed Latif Bekci
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Von Mises Stress ◽  
Principal Stresses ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
3D Fea ◽  
Von Mises ◽  
Three Dimensional Finite Element

BACKGROUND: Zirconia has become a popular biomaterial in dental implant systems because of its biocompatible and aesthetic properties. However, this material is more fragile than titanium so its use is limited. OBJECTIVES: The aim of this study was to compare the stresses on morse taper implant systems under parafunctional loading in different abutment materials using three-dimensional finite element analysis (3D FEA). METHODS: Four different variations were modelled. The models were created according to abutment materials (zirconia or titanium) and loading (1000 MPa vertical or oblique on abutments). The placement of the implants (diameter, 5.0 × 15 mm) were mandibular right first molar. RESULTS: In zirconia abutment models, von Mises stress (VMS) values of implants and abutments were decreased. Maximum and minimum principal stresses and VMS values increased in oblique loading. VMS values were highest in the connection level of the conical abutments in all models. CONCLUSIONS: Using conical zirconia abutments decreases von Mises stress values in abutments and implants. However, these values may exceed the pathological limits in bruxism patients. Therefore, microfractures may be related to the level of the abutment.

Study on Stability of High Embankments on Rock Slope under Complicated Stress Conditions

2011 ◽  
Vol 368-373 ◽  
pp. 1642-1648
Author(s):  
Gui Ling Ding
Keyword(s):  
Finite Element ◽  
Slip Surface ◽  
Three Dimensional ◽  
Slope Instability ◽  
Instability Criterion ◽  
Two Dimensional ◽  
Study Results ◽  
Geological Conditions ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Three-dimensional finite element analysis should be used in stability analysis of slope because it can overcome the short advantages of two-dimensional finite element and can simulate the complex topographic and geological conditions. Based on the large-scale triaxial shear test, the modified Duncan-Chang model is established. Based on strength reduction elasto-plastic finite element, stability of high fill embankment was studied with three-dimensional finite element method considering the complex terrain conditions. Study results suggest that plastic strain and displacement mutant of slip surface node can be a sign of slope instability as a whole. At the same time calculation of three-dimensional finite element also does not converge. Therefore, it can be slope instability criterion calculate whether the finite element static analysis converges or not. On the other hand, stability safety factor of high fill embankment under three-dimensional conditions is larger than that of two-dimensional conditions, which shows that boundary conditions of high fill embankment enhance its stability.

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