About the Influence of the Corrosion Defect Geometry on Repaired Pipes Stress Distribution

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Ionut Lambrescu ◽  
Alin Dinita ◽  
Mihail Minescu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Surface Defects ◽  
Three Dimensional ◽  
Stress Distributions ◽  
Pipe Axis ◽  
Element Analysis ◽  
New Approach ◽  
Defect Area ◽  
Different Shapes

Abstract This paper proposes a new approach in dealing with volumetric surface defects (VSD) in pipelines. Using three-dimensional (3D) scanning and reverse engineering techniques, along with finite element analysis, we studied and evaluated comparatively the stress distributions in the defect area for different shapes and positions of the machined VSD, in order to find the best solution for the repairing process using composite materials. Our main conclusion is that instead of machining the VSD such as to generate a rectangular shaped machined defect, with edges parallel/perpendicular to the pipe axis, it is better to mold the VSD. Another possible solution would be to machine the real VSD such as to generate an inclined rectangle that circumscribes the defect. This paper also studies the influence of the machined defect filet radius to the bottom of the VSD.

scholarly journals Comparison of Tooth- and Bone-Borne Appliances on the Stress Distributions and Displacement Patterns in the Facial Skeleton in Surgically Assisted Rapid Maxillary Expansion—A Finite Element Analysis (FEA) Study

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1152
Author(s):  
Rafał Nowak ◽  
Anna Olejnik ◽  
Hanna Gerber ◽  
Roman Frątczak ◽  
Ewa Zawiślak
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Rapid Maxillary Expansion ◽  
Stress Distributions ◽  
Maxillary Expansion ◽  
Facial Skeleton ◽  
Element Analysis ◽  
Maxillary Constriction

The aim of this study was to compare the reduced stresses according to Huber’s hypothesis and the displacement pattern in the region of the facial skeleton using a tooth- or bone-borne appliance in surgically assisted rapid maxillary expansion (SARME). In the current literature, the lack of updated reports about biomechanical effects in bone-borne appliances used in SARME is noticeable. Finite element analysis (FEA) was used for this study. Six facial skeleton models were created, five with various variants of osteotomy and one without osteotomy. Two different appliances for maxillary expansion were used for each model. The three-dimensional (3D) model of the facial skeleton was created on the basis of spiral computed tomography (CT) scans of a 32-year-old patient with maxillary constriction. The finite element model was built using ANSYS 15.0 software, in which the computations were carried out. Stress distributions and displacement values along the 3D axes were found for each osteotomy variant with the expansion of the tooth- and the bone-borne devices at a level of 0.5 mm. The investigation showed that in the case of a full osteotomy of the maxilla, as described by Bell and Epker in 1976, the method of fixing the appliance for maxillary expansion had no impact on the distribution of the reduced stresses according to Huber’s hypothesis in the facial skeleton. In the case of the bone-borne appliance, the load on the teeth, which may lead to periodontal and orthodontic complications, was eliminated. In the case of a full osteotomy of the maxilla, displacements in the buccolingual direction for all the variables of the bone-borne appliance were slightly bigger than for the tooth-borne appliance.

Pre-Collapse Stress Redistributions in Femoral Head Osteonecrosis—A Three-Dimensional Finite Element Analysis

1983 ◽  
Vol 105 (2) ◽  
pp. 171-176 ◽  
Author(s):  
T. D. Brown ◽  
G. L. Hild
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Stress Distributions ◽  
Element Analysis ◽  
Strong Function ◽  
Apparent Modulus ◽  
Femoral Head Osteonecrosis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Three-dimensional finite element analysis is used to explore the influence of several lesion characteristics upon mechanical stress distributions in segmentally necrotic human femoral heads. Variables studied parametrically included apparent modulus deficits within the lesion proper, as well as the depth, width, and location of the infarcted head regions. The detailed patterns of stress redistribution were complex and were found to be a strong function of the specific lesion characteristics. The salient phenomenon, however, was one of preferential load uptake by the stiffer bone surrounding the lesion. Since computed stress reductions within the infarctions were usually much smaller than experimentally observed strength reductions, the data suggest a strong tendency for an elevated incidence of trabecular fatigue fractures in the affected regions.

scholarly journals Evaluation of stress distributions in peri-implant and periodontal bone tissues in 3- and 5-unit tooth and implant-supported fixed zirconia restorations by finite elements analysis

2015 ◽  
Vol 09 (03) ◽  
pp. 329-339 ◽  
Author(s):  
Sedat Guven ◽  
Koksal Beydemir ◽  
Serkan Dundar ◽  
Veysel Eratilla
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Stress Distributions ◽  
Finite Elements Analysis ◽  
Element Analysis ◽  
3D Finite Element ◽  
Cervical Portion ◽  
Distribution Of Stress ◽  
Stress Accumulation

ABSTRACT Objective: In this study, it is aimed to compare the distribution of stress on periodontal and peri-implant bone tissues in 3- and 5-unit-dental and implant-supported zirconia restorations using finite element analysis. Materials and Methods: Stress distribution formed in periodontal and peri-implant bone tissues as a result of chewing forces was analyzed in dental and implant-supported three-dimensional (3D) finite element models of zirconia restoration with 5-unit placed on the numbers of 43, 44, 45, 46, and 47 and with 3-unit placed on the number of 45, 46, and 47. Four different loading conditions were used. 200 N force was applied in 30° from the buccal inclination of number 43, 45, and 47 restorations separately and totally 850 N force was applied in 30° from the buccal inclination of whole restoration. The study was performed through static nonlinear analysis with the 3D finite element analysis method. Results: Stress accumulation in bone tissues in the tooth-supported model was found less than in implant-supported models. Stress accumulation was observed in the cervical portion of the implant in implant-supported models, and stress accumulation was observed surrounding bone of roots in tooth-supported models. The highest stress values were occurred in 5 unit implant-supported model in all loadings. Conclusion: In posterior restorations increased in the number of supported teeth and implant can reduce the destructive forces on periodontal and peri-implant bone tissues and may allow longer period retention of the restorations in the mouth.

scholarly journals Evaluation of the Ko-Len Model for Enterlaminar Stresses in Composite Laminates with an Open Hole

1996 ◽  
Vol 5 (5) ◽  
pp. 096369359600500 ◽  
Author(s):  
F. Z. Hu ◽  
C. Soutis
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Laminates ◽  
Three Dimensional ◽  
Tensile Loading ◽  
Stress Distributions ◽  
Element Analysis ◽  
Open Hole ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The purpose of this paper is to evaluate a recently developed analytical model [1] which determines the interlaminar stress distributions around a circular hole in symmetric composite laminates under in-plane tensile loading. For this purpose, a three-dimensional finite element analysis is performed and the stress distributions for symmetric cross-ply laminates are presented This work is relevant to the prediction of delamination onset load and location around the discontinuity.

Finite Element Analysis of Bioprosthetic Heart Valve on Suture Densities

2013 ◽  
Vol 706-708 ◽  
pp. 1348-1352
Author(s):  
Xia Zhang ◽  
Quan Yuan ◽  
Xu Huang ◽  
Hai Bo Ma
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Heart Valve ◽  
Stress Distributions ◽  
Bioprosthetic Heart Valve ◽  
Element Analysis ◽  
Different Shapes ◽  
Valve Model

In order to improve long-term durability of bioprosthetic heart valve, stress distribution of bioprosthetic heart valve leaflets with different shapes and suture density under the same load is analyzed and compared based on finite element method.The finite element analysis results are compared with each valve model, it shows that suture density has a significant effect on the dynamic behavior of the bioprosthetic heart valve, which may lead not only to different stress peak values, but also to different stress distributions and deformation. This work can be very helpful when manufacturing the bioprosthetic heart valve.

scholarly journals A Three-Dimensional Finite Element Analysis of Displacement and Stress Distributions of Unilateral and Bilateral Cleft Lips by Using Developed Pre-Surgical Treatment Architecture

Children ◽  
2021 ◽  
Vol 8 (12) ◽  
pp. 1121
Author(s):  
Ali A. H. Karah bash ◽  
Ergun Ercelebi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Surgical Treatment ◽  
Three Dimensional ◽  
Surgical Techniques ◽  
Control Unit ◽  
External Stress ◽  
Von Mises Stress ◽  
Stress Distributions ◽  
Element Analysis

Cleft lips and cleft palates are the most common birth defects in newborns. Pre-surgical correction of unilateral and bilateral cleft lips and palates has been the subject of interest of many previous works. This condition has necessitated the evolution of many surgical and non-surgical techniques to mitigate the problem of this deformity in children. In this study, we proposed a new architecture that can be used instead of the conventional pre-surgical treatment. The proposed architecture has mechanical and electronic parts. This architecture was adopted to apply external stress to the cleft bones and cleft edges using an airbag that is located in the mechanical part. The amount of air in the airbag can be controlled by an available control unit in the electronic part. The effect of external stress on the cleft bones and the cleft edges was analyzed by using the finite element analysis (FEA) method. The FEA study aimed to analyze the displacement, amount of tensile and compressive forces, and Von Mises stress distributions on the cleft bones, cleft edges, nasal septum, and superior alveolar part of the maxillary jaw of unilateral and bilateral cleft models during pre-surgical treatment with the novel architecture. The results show that displacement and stress affected the clefts of both models. Displacement had a significant effect of gradually bringing the clefts closer to each other and returning them to the posterior. The analysis also investigated the effects of stress on the cleft bone and cleft edge. It was found from the results that the stresses helped to bring the incisions closer to the most appropriate position for plastic surgeons. The results prove that the positive and negative X-displacements move in the opposite direction, which means that the cleft edges gradually converge toward each other. Moreover, the negative Z-displacement affected the movement of cleft bones and cleft edges from outside to inside and gradually returned them to a suitable position. The findings show that the proposed architecture can be contributed to the pre-surgical treatment of the unilateral and bilateral clefts as an alternative to the traditional method.

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