scholarly journals Effect of Different Surface Designs on the Rotational Resistance and Stability of Orthodontic Miniscrews: A Three-Dimensional Finite Element Study

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 1964
Author(s):  
Jin-Young Choi ◽  
Jaehee Cho ◽  
Song Hee Oh ◽  
Seong-Hun Kim ◽  
Kyu-Rhim Chung ◽  
...  
Keyword(s):  
Finite Element ◽  
Trabecular Bone ◽  
Cortical Bone ◽  
Three Dimensional ◽  
Middle Part ◽  
Element Analysis ◽  
Applied Forces ◽  
The Stability ◽  
The Moment ◽  
Rotational Resistance

High orthodontic forces and various directions of applied forces can be associated with loosening of the screw anchorage in the bone. Screw designs have been modified to increase the stability of the miniscrews. This research evaluates the influence of three-designs on the stability of orthodontic miniscrews. A conventionally cylinder-type miniscrew design (Bio-Action screw, Jin-Biomed co., Bucheon, Korea) was set as a control, and three conditions were studied based on modifications of this control design. Condition-1 has narrowed threads in the upper part of the screw; Condition-2 has a notch at the middle part; and Condition-3 has the combination of Condition-1 and Condition-2. The moment required to unwind the miniscrew to five degrees is tested, and the moment generated at the cortical bone and the trabecular bone were calculated with finite element analysis. Compared to the control, all three conditions showed a higher moment required to unwind the miniscrew and a higher moment generated at the cortical bone. At the trabecular bone, condition-2 and -3 showed higher moment than the control, and condition-1 showed similar moment to the control. Condition-3 required a higher overall moment to unwind the miniscrew. These findings validate the design modifications used to increase the rotational resistance.

Structural Stability Evaluation for Lifting Lug Design of Large Marine Engine by Finite Element Analysis

2007 ◽  
Vol 353-358 ◽  
pp. 2855-2859
Author(s):  
W.C. Lee ◽  
Chae Sil Kim ◽  
J.B. Na ◽  
D.H. Lee ◽  
S.Y. Cho ◽  
...  
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Design Procedure ◽  
Steel Structures ◽  
Stability Evaluation ◽  
Element Analysis ◽  
Marine Engines ◽  
Dimensional Finite Element ◽  
The Stability ◽  
Three Dimensional Finite Element

Since most marine engines are generally very huge and heavy, it is required to keep safety from accidents in dealing them. Several types of lifting lugs have been used to assemble hundred ton–large steel structures and carry the assembled engines. Recently a few crashes have been occurred in carrying engines due to breaking down the lugs. Although the stability evaluation of the lifting lug has therefore been very important for safety, systematic design procedure of the lugs, which includes the structural analysis considering stability, has few reported. This paper describes the three dimensional finite element structural modeling for a lifting lug, the studies for determining the reasonable loading and boundary conditions, and the stability evaluation with the results of structural analyses. It should be very helpful for designing the other types of lifting lugs with safety.

Finite Element Simulation and Analysis for the Working Process of Working-Roll of Carder

2013 ◽  
Vol 670 ◽  
pp. 76-79
Author(s):  
Bao Guo Yang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Radial Displacement ◽  
Three Dimensional ◽  
Work Roll ◽  
Middle Part ◽  
Working Process ◽  
Element Analysis ◽  
Analog Simulation ◽  
Roll Axis

The three-dimensional models of the Working-roll of Carder are founded by three-dimensional design software Solidworks and the working process of Working-rolls is simulated by finite element analysis software Cosmos, which obtain overall stress distribution for the Working-roll of Carder. The relations between the working-rolls with different thickness and different length of work roll axis and the stress, strain and radial displacement in the working process of working-rolls are attained by finite element analysis and the important factors of impact of work roll deformation are indicated by analog simulation. The results show that the maximum stress and maximum strain are occur in the place of roller connected with the axis rather than to appear in the middle part of roller and the radial displacement in the working process of working-rolls and the length of work roll axis are not directly relationship. The Finite element analysis results provide an important theoretical basis to design a reasonable the length of axis and the thickness of roller for the working-roll of carder.

Finite Element Analysis of an Osseointegrated Stepped Screw Dental Implant

2004 ◽  
Vol 30 (4) ◽  
pp. 223-233 ◽  
Author(s):  
J. P. Geng ◽  
W. Xu ◽  
K. B. C. Tan ◽  
G. R. Liu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Trabecular Bone ◽  
Cortical Bone ◽  
Dental Implant ◽  
Elastic Moduli ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Data Set ◽  
Bone Level

Abstract An osseointegrated stepped screw dental implant was evaluated using 2-dimensional finite element analysis (FEA). The implant was modeled in a cross section of the posterior human mandible digitized from a computed tomography (CT) generated patient data set. A 15-mm regular platform (RP) Branemark implant with equivalent length and neck diameter was used as a control. The study was performed under a number of clinically relevant parameters: loading at the top of the transmucosal abutment in vertical, horizontal, and 45° oblique 3 orientations. Elastic moduli of the mandible varied from a normal cortical bone level (13.4 GPa) to a trabecular bone level (1.37 GPa). The study indicated that an oblique load and elastic moduli of the cortical bone are important parameters to the implant design optimization. Compared with the cylindrical screw implant, the maximum von Mises stress of the stepped screw implant model was 17.9% lower in the trabecular bone-implant area. The study also showed that the stepped screw implant is suitable for the cortical bone modulus from 10 to 13.4 GPa, which is not necessarily as strict as the Branemark implant, for which a minimum 13.4 GPa cortical bone modulus is recommended.

scholarly journals A Three-dimensional Finite Element Analysis of Stress Distribution in the Cortical Bone in Single Tooth Implant and Post Core-treated Tooth subjected to variable Loads

2017 ◽  
Vol 7 (1) ◽  
pp. 8-16
Author(s):  
Suneetha Rao ◽  
Honey Arora ◽  
Shahul Hameed
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Cortical Bone ◽  
Three Dimensional ◽  
Element Analysis ◽  
Single Tooth ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Single Tooth Implant

ABSTRACT Purpose In spite of many advances in the field of prosthetic dentistry, the choice of whether to treat and retain a grossly compromised tooth or to extract and replace with an implant is debatable. Alveolar bone preservation is one of the main criteria to select the treatment option. This is directly affected by the stress generated in the cortical bone under variable loads and is therefore, relevant. Materials and methods Two three-dimensional finite element models were generated in relation to maxillary second premolar using ANSYS software. Model-I was parallel-tapered titanium implant with screw-retained titanium abutment and porcelain fused to metal (PFM) crown. Model-P was fiber post and com- posite resin core with PFM crown. Luting cement was resin cement. Both the models were surrounded by homogeneous and isotropic cortical and cancellous bone, and were subjected to variable loads of 300, 400, and 500 N in axial (0°) and nonaxial (15°, 45°) directions. Results Stress in the cortical bone in megapascal (MPa) in Model-I/Model-P when subjected to variable loads in newtons(N) in axial direction was 300 N - 37.6 MPa/47.3 MPa; 400 N - 50.2 MPa/63.0 MPa; 500 N - 62.7 MPa/63.0 MPa. 15°- 300 N - 68.5 MPa/65.9 MPa; 400 N - 91.3 MPa/87.9 MPa; 500 N - 114.2 MPa/87.9 MPa. 45° - 300 N - 136.3 MPa/88.9 MPa; 400 N - 181.8 MPa/118.5 MPa; 500 N - 227.2 MPa/118.5 MPa. Conclusion Within the limitation of this study, it was concluded that on axial loading, both the treatment modalities showed no significant difference, but on nonaxial loading, the cortical bone in the implant model showed to have considerably higher stress than post core-treated tooth model. Hence, given a choice, this study favors retaining and restoring a compromised tooth with post core and crown rather than extracting and replacing with an implant. How to cite this article Rao S, Arora H, Hameed S. A Three- dimensional Finite Element Analysis of Stress Distribution in the Cortical Bone in Single Tooth Implant and Post Core-treated Tooth subjected to variable Loads. Int J Prosthodont Restor Dent 2017;7(1):8-16.

Three-Dimensional Modeling and Finite Element Analysis of an Ankle External Fixator

2020 ◽  
Vol 899 ◽  
pp. 94-102
Author(s):  
Nur Faiqa Ismail ◽  
Muhammmad Aiman Firdaus Bin Adnan ◽  
Solehuddin Shuib ◽  
Nik Ahmad Hambali Nik Abd Rashid
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
External Fixator ◽  
Three Dimensional ◽  
Von Mises Stress ◽  
External Fixators ◽  
Element Analysis ◽  
Stress And Deformation ◽  
The Stability ◽  
Von Mises

External fixator has played an important role in repairing fractured ankle bone. This surgery is done due to the several factors which are the bone is not normal position or has broken into several pieces. The external fixator will help the broken bone to grow and remodel back to the original appearance. However, there are some issues regarding to the stability of this fixation. Improper design and material are the major factor that decreased the stability since it is related to the deformation of the external fixator to hold the bone fracture area. This study aims to design a stable structure for constructing delta frame ankle external fixator to increase the stability of the fixation. There are two designs of external fixator with two types of material used in this present study. Both external fixators with different materials are analyzed in terms of von Mises stress and deformation by using a conventional Finite Element Analysis software; ANSYS Workbench V15. The result obtained shows the Model 1 with stainless steel has less stress and deformation distributions compared to the Model 2. Hence, by using Model 1 as the external fixator, the stability of the fixation can be increased.

Optimization of Seepage Prevention of Ma Erdang Hydropower Station

2014 ◽  
Vol 1065-1069 ◽  
pp. 619-624
Author(s):  
Li Ting Qiu ◽  
Zhen Zhong Shen ◽  
Xiao Hu Tao
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Seepage Flow ◽  
Design Stage ◽  
Seepage Discharge ◽  
Element Analysis ◽  
Seepage Control ◽  
Calculation Results ◽  
Dam Site ◽  
The Stability

Base on the design of seepage control, the three-dimensional non-steady saturated - unsaturated seepage finite element analysis program CNPM3D is used to establish the three-dimentional finite element seepage model of junction area during operating period. The seepage field of dam site area is studied under the different anti-seepage curtain arrangement scheme. Specifically, the seepage gradient and the seepage discharge of the panel, major material zone, foundation curtains and two sides abutment curtains are analyzed to evaluate the stability of the major district of dam area, in order to provide suggestions for choosing the seepage control standard in the next deepen design stage.The calculation results show that the panel and the impervious curtain anti-seepage effect is remarkable.Impervious curtain can greatly reduce the total seepage flow of the dam and its foundation.However the curtain deepened to 1Lu has little effect on seepage discharge. It is showed that the seepage prevention standards of 3 lu should be proposed in the deepen design stage for both security and economic benefit. The achievement and experience of this seepage prevention design should be taken into consideration for other similar projects.

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