Modeling of Stress Distribution in Dental Implant in Frontal Part of Mandible

2014 ◽  
Vol 606 ◽  
pp. 137-140
Author(s):  
Dušan Németh ◽  
Ján Kučera ◽  
František Lofaj ◽  
Vladimír Ivančo
Keyword(s):  
Stress Distribution ◽  
Stress Field ◽  
Dental Implant ◽  
Fem Analysis ◽  
Screw Thread ◽  
Bone Surface ◽  
Normal Position ◽  
Lower Stress ◽  
Frontal Part ◽  
Maximum Stresses

The aim of this work is the modeling of the stress distribution in cortical and trabecular bone of model frontal part of mandible by FEM analysis using linear static methods applying monocortical and bicortical fixation of dental implant. Depending on the position of the screw thread with regard to the bone surface, three different cases were simulated: exactly on the bone surface, 1,5 mm above and 0,5 mm below the surface of the cortical bone. It was found out that the stress field in the cortical part and the implant are considerably lower in the case of slightly recessed position in contrast with the above and normal position of the implant in both, monocortical and bicortical fixations. However, bicortical fixation in this case generates slightly lower stress field in the bone and implant parts than in monocortical fixation. Monocortical fixation is otherwise slightly more favorable from the viewpoint of maximum stresses in the bone in the case of exact and above positions of the implant.

The Effect of the Cortical Bone Thickness on the Stress Distribution in Dental Implants by FEM

2015 ◽  
Vol 662 ◽  
pp. 151-154
Author(s):  
Dušan Németh ◽  
František Lofaj ◽  
Ján Kučera
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Distribution ◽  
Cortical Bone ◽  
Dental Implant ◽  
Axial Loading ◽  
Bending Moment ◽  
Bone Thickness ◽  
Cortical Bone Thickness ◽  
Maximum Stresses

The stress distribution in cortical bone and dental implant has been modeled by finite element method (FEM) using linear static analysis in the case of monocortical and bicortical fixation of a real dental implant for three cortical bone thicknesses: 2 mm, 2.5 mm, 4 mm. The analysis revealed that the highest stresses in the cortical bone and in the implant after three-axial loading are localized at the edge of the cortical bone near the implant neck where bending moment is the highest. An increase of the maximum stresses has been observed with the decrease of the intraosseal length of the implant and cortical bone thickness.

scholarly journals Analytical Investigation of Viscoelastic Stagnation-Point Flows with Regard to Their Singularity

2021 ◽  
Vol 11 (15) ◽  
pp. 6931
Author(s):  
Jie Liu ◽  
Martin Oberlack ◽  
Yongqi Wang
Keyword(s):  
Stress Distribution ◽  
Stress Field ◽  
Stagnation Point ◽  
Analytical Solutions ◽  
Wide Spectrum ◽  
Momentum Conservation ◽  
Stagnation Point Flow ◽  
Model Parameters ◽  
Viscoelastic Models ◽  
Special Cases

Singularities in the stress field of the stagnation-point flow of a viscoelastic fluid have been studied for various viscoelastic constitutive models. Analyzing the analytical solutions of these models is the most effective way to study this problem. In this paper, exact analytical solutions of two-dimensional steady wall-free stagnation-point flows for the generic Oldroyd 8-constant model are obtained for the stress field using different material parameter relations. For all solutions, compatibility with the conservation of momentum is considered in our analysis. The resulting solutions usually contain arbitrary functions, whose choice has a crucial effect on the stress distribution. The corresponding singularities are discussed in detail according to the choices of the arbitrary functions. The results can be used to analyze the stress distribution and singularity behavior of a wide spectrum of viscoelastic models derived from the Oldroyd 8-constant model. Many previous results obtained for simple viscoelastic models are reproduced as special cases. Some previous conclusions are amended and new conclusions are drawn. In particular, we find that all models have singularities near the stagnation point and most of them can be avoided by appropriately choosing the model parameters and free functions. In addition, the analytical solution for the stress tensor of a near-wall stagnation-point flow for the Oldroyd-B model is also obtained. Its compatibility with the momentum conservation is discussed and the parameters are identified, which allow for a non-singular solution.

scholarly journals 1011 FEM Analysis on the Effect of the Slip on Stress Field in Wheel Tread with White Layer

2009 ◽  
Vol 2009.47 (0) ◽  
pp. 347-348
Author(s):  
Ryota KONO ◽  
Hiroyuki AKEBONO ◽  
Masahiko KATO ◽  
Atsushi SUGETA
Keyword(s):  
Stress Field ◽  
White Layer ◽  
Fem Analysis

Fast Reconstruction Method of the Stress Field for the Steam Turbine Rotor Based On Deep Fully Convolutional Network

2021 ◽  
Author(s):  
Ding Guo ◽  
Tianyuan Liu ◽  
Di Zhang ◽  
Yonghui Xie
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Stress Field ◽  
Temperature Measurement ◽  
Turbine Rotor ◽  
Convolutional Network ◽  
Fully Convolutional Network ◽  
Start Up ◽  
Fast Reconstruction ◽  
Reconstruction Model

Abstract Since it is difficult to directly measure the transient stress of a steam turbine rotor in operation, a rotor stress field reconstruction model based on deep fully convolutional network for the start-up process is proposed. The stress distribution in the rotor can be directly predicted based on the temperature of a few measurement points. First, the finite element model is used to accurately simulate the temperature and stress field of the rotor start-up process, generating training data for the deep learning method. Next, data of only 15 temperature measurement points are arranged to predict the stress distribution in critical area of the rotor surface, with the accuracy (R2-score) reaching 0.997. The time cost of the trained neural network model at a single case is 1.42s in CPUs and 0.11s in GPUs, shortened by 97.3% and 99.8% with comparison to finite element analysis, respectively. In addition, the influence of the number of temperature measurement points and the training size are discussed, verifying the stability of the model. With the advantages of fast calculation, high accuracy and strong stability, the fast reconstruction model can effectively realize the stress prediction during start-up processes, resulting in the possibility of real-time diagnosis of rotor strength in operation.

Analytical-Numerical Determination of Stress Distribution around a Tip of Polygon-Like Inclusion

2016 ◽  
Vol 713 ◽  
pp. 94-98
Author(s):  
Ondřej Krepl ◽  
Jan Klusák ◽  
Tomáš Profant
Keyword(s):  
Stress Distribution ◽  
Stress Field ◽  
Numerical Procedure ◽  
Plane Elasticity ◽  
Necessary Condition ◽  
Singular Stress ◽  
Reliable Assessment ◽  
Generalized Stress Intensity Factors ◽  
Stress Behaviour

A stress distribution in vicinity of a tip of polygon-like inclusion exhibits a singular stress behaviour. Singular stresses at the tip can be a reason for a crack initiation in composite materials. Knowledge of stress field is necessary condition for reliable assessment of such composites. A stress field near the general singular stress concentrator can be analytically described by means of Muskhelishvili plane elasticity based on complex variable functions. Parameters necessary for the description are the exponents of singularity and Generalized Stress Intensity Factors (GSIFs). The stress field in the closest vicinity of the SMI tip is thus characterized by 1 or 2 singular exponents (1 - λ) where, 0<Re (λ)<1, and corresponding GSIFs that follow from numerical solution. In order to describe stress filed further away from the SMI tip, the non-singular exponents for which 1<Re (λ), and factors corresponding to these non-singular exponents have to be taken into account. Analytical-numerical procedure of determination of stress distribution around a tip of sharp material inclusion is presented. Parameters entering to the procedure are varied and tuned. Thus recommendations are stated in order to gain reliable values of stresses and displacements.

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)

scholarly journals The FEM Analysis of Stress Distribution in front of the Crack Tip and Fracture Process in the Elements of Modified and Unmodified Cast Steel G17CrMo5-5

2016 ◽  
Vol 10 (3) ◽  
pp. 201-206
Author(s):  
Robert Pała ◽  
Ihor Dzioba
Keyword(s):  
Stress Distribution ◽  
Cleavage Fracture ◽  
Crack Extension ◽  
Cast Steel ◽  
Experimental Studies ◽  
Fem Analysis ◽  
Initial Moment ◽  
Stress Distributions ◽  
Calculated Stress

Abstract The article presents influence of modification of the low-alloy cast steel G17CrMo5-5 by rare earth metals on stress distribution in front of the crack at the initial moment of the crack extension. Experimental studies include determination of strength and fracture toughness characteristics for unmodified (UM) and modified (M) cast steel. In the numerical computations, experimentally tested specimens SEN(B) were modelled. The true stress–strain curves for the UM and M cast steel are used in the calculation. The stress distributions in front of the crack were calculated at the initial moment of the crack extension. On the basis of data on the particle size inclusions in the UM and M cast steel, and the calculated stress distributions was performed an assessment of the possibility of the occurrence of cleavage fracture. The analysis results indicate that at room temperature for the UM cast steel, there is a possibility of cleavage fracture, while for the M cast steel occurrence of cleavage fracture is negligible.

The Principal Stress Distribution in a Root with a Loaded Post in Model Experiments

1977 ◽  
Vol 56 (12) ◽  
pp. 1463-1467 ◽  
Author(s):  
Tore Dérand
Keyword(s):  
Stress Distribution ◽  
Principal Stress ◽  
Root Canal ◽  
Model Experiments ◽  
Cement Layer ◽  
Maximum Stresses

The princapal stress distribution in a root with a loaded post was analyzed in model experiments, in which emphasis was directed to the cervical boundary of the root where the stresses are greatest. Maximum stresses were found in the inner proximal sides, and were stronger when the prepared root canal walls were parallel. When contact between post and root was reduced, stresses decreased. These findings point to the importance of sparing tooth substance in the proximal parts of the canal in order to reduce the risk of breaking the cement layer and loosening the post.

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