scholarly journals Finite element analysis of stresses on adjacent teeth during the traction of palatally impacted canines

2018 ◽  
Vol 89 (3) ◽  
pp. 418-425 ◽  
Author(s):  
Kinan G. Zeno ◽  
Samah J. El-Mohtar ◽  
Samir Mustapha ◽  
Joseph G. Ghafari

ABSTRACT Objective: To evaluate stresses on maxillary teeth during alignment of a palatally impacted canine (PIC) under different loading conditions with forces applied in vertical and buccal directions. Materials and Methods: A three-dimensional finite element model of the maxilla was developed from a cone beam computed tomographic scan of a patient with a left PIC. Traction was simulated under different setups: (1) palatal spring extending from a transpalatal bar (TPB) anchored on the first molars (M1) and alternatively combined with different archwires (0.016 × 0.022-inch; 0.018 × 0.025-inch) with and without engaging second molars and (2) a buccal force against 0.018-inch, 0.016 × 0.022-inch, and 0.018 × 0.025-inch archwires with and without engaging the left lateral incisor (I2). Results: Without fixed appliances, stresses were assumed by M1; with fixed appliances, stresses were distributed on all teeth, decreasing mesially toward the midline. Direct buccal pull exerted most stress on neighboring I2 (19–20% with different wire sizes) and first premolar (12–17%), decreasing distally, along a similar pattern with different archwire sizes. When I2 was bypassed, stresses on adjacent teeth increased only by 3–6%. Higher stresses occurred with the lighter round wire. Conclusions: This first research on stresses on adjacent teeth during PIC traction provided needed quantitative data on the pattern of stress generation, suggesting the following clinical implications: use of distal-vertical pull from posterior anchorage (TPB) as initial movement and when using a buccal force, bypassing the lateral incisor and using heavier wires that would minimize side effects.

2013 ◽  
Vol 103 (3) ◽  
pp. 174-180 ◽  
Author(s):  
Mehmet Serhan Er ◽  
Ozgur Verim ◽  
Levent Altinel ◽  
Suleyman Tasgetiren

Background: Use of thicker and longer (four cortices) screws or of multiple screws seems to be more stable and efficient for syndesmosis fixation. Methods: A three-dimensional finite element model of an ankle was constructed from serial axial sections from an existing two-dimensional computed tomographic image. Constructions of syndesmosis fixation with 3.5-mm single tricortical, 3.5-mm single quadricortical, 3.5-mm double tricortical, 3.5-mm double quadricortical, 4.5-mm single tricortical, and 4.5-mm single quadricortical screws were performed on this model. Physiologic loads approximating those during stance phase normal walking were applied to this ankle system. Stress values on the screws using the six fixation methods were compared. Results: The highest maximum stress was determined over 3.5-mm cortical screws applied as single quadricortical, and the lowest maximum stress was determined over the 4.5-mm cortical screw applied as single quadricortical. Stress on the 3.5-mm single screw with quadricortical application was found to be higher than that with tricortical application and also compared with the 4.5-mm quadricortical screw application. Differences between the 4.5-mm single tricortical and quadricortical screws and between the 3.5-mm single tricortical and 3.5-mm double tricortical screw applications were not significant. Conclusions: Quadricortical application of 3.5-mm single screws and tricortical application of 3.5-mm double cortical screws are not good choices for syndesmosis fixation. If the plan is tricortical application, a 3.5-mm single cortical screw is adequate. If quadricortical application of syndesmosis fixation is planned, a 4.5-mm cortical screw should be used. (J Am Podiatr Med Assoc 103(3): 174–180, 2013)


2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.


2011 ◽  
Vol 291-294 ◽  
pp. 3282-3286 ◽  
Author(s):  
Jiang Wei Wu ◽  
Peng Wang

In port crane industry, the surface hardening technique is widely used in order to improve the strength of wheel. But the hardening depth is chosen only by according to the experience, and the effect of different hardened depths is not studied theoretically. In this paper, the contact stresses in wheel with different hardening depth have been analyzed by applying three-dimensional finite element model. Based on this model, the ANSYS10.0 finite element software is used. The elastic wheel is used to verify the numerical results with the Hertz’s theory. Three different hardening depths, namely 10mm, 25mm and whole hardened wheel, under three different vertical loads were applied. The effect of hardening depth of a surface hardened wheel is discussed by comparing the contact stresses and contact areas from the numerical results.


2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Zhun Xu ◽  
Yikai Li ◽  
Shaoqun Zhang ◽  
Liqing Liao ◽  
Kai Wu ◽  
...  

Abstract Background Clinical studies have found that manipulations have a good clinical effect on sacroiliac joint (SIJ) pain without specific causes. However, the specific mechanisms underlying the effect of manipulations are still unclear. The purpose of this study was to investigate the effects of three common manipulations on the stresses and displacements of the normal SIJ and the strains of the surrounding ligaments. Methods A three-dimensional finite element model of the pelvis-femur was developed. The manipulations of hip and knee flexion (MHKF), oblique pulling (MOP), and lower limb hyperextension (MLLH) were simulated. The stresses and displacements of the SIJ and the strains of the surrounding ligaments were analyzed during the three manipulations. Results MOP produced the highest stress on the left SIJ, at 6.6 MPa, while MHKF produced the lowest stress on the right SIJ, at 1.5 MPa. The displacements of the SIJ were all less than 1 mm during the three manipulations. The three manipulations caused different degrees of ligament strain around the SIJ, and MOP produced the greatest straining of the ligaments. Conclusion The three manipulations all produced small displacements of the SIJ and different degrees of ligament strains, which might be the mechanism through which they relieve SIJ pain. MOP produced the largest displacement and the greatest ligament strains.


2018 ◽  
Vol 10 (6) ◽  
pp. 168781401877847 ◽  
Author(s):  
Daniela Maffiodo ◽  
Raffaella Sesana ◽  
Dino Paolucci ◽  
Sabrina Bertaggia

A procedure to design the spiral springs finite life for dual-mass flywheels is presented. Due to design constraints, installation space, production processes, stiffness requirement, maximum torque, and maximum speed, these components are dimensioned for finite life. Two- and three-dimensional finite element model static structural analysis was performed to obtain the stress distribution, deformed shape, and to validate optimization design. The fatigue analysis was performed both experimentally and by means of a component life estimation model. An experimental duty cycle was applied. Finite element analysis and experimental analysis agree in pointing out the location and the value of maximum stresses and the shape of deformation. Vehicle tests highlight premature spiral springs’ failures, which do not agree with life estimation. The examination of the fracture showed that fretting and wear, along with fatigue phenomena, are the causes of premature failures. A dedicated component life estimation model is required, taking into account of wear and loading history.


2013 ◽  
Vol 838-841 ◽  
pp. 540-544 ◽  
Author(s):  
Jian Rong Pan ◽  
Zhan Wang ◽  
Lin Qiang Zheng ◽  
Zheng Ting Yang

Beam-column connection with cantilever beam bolted-splicing is also known as the joint of column-tree moment-resisting frame. The study is still relatively small for the semi-rigid behavior and rotational stiffness of the joint. This paper deal with four specimens of the joints with cantilever beam splicing and four specimens of the welded joints by using three dimensional finite element model analysis. The strain, stress, yield and ultimate loads, yield and ultimate deformations had been compared between the joint with cantilever beam splicing and the welded joint. The analysis results show that, when the splicing area of the joint with cantilever beam splicing was designed more strongly, the stress distribution, the load-displacement curves in elastic working stage, and the initial rotational stiffness are good agreement between the joint with cantilever beam splicing and the welded joint. The hysteresis curves of the joint with cantilever beam splicing were inverse S-shaped, indicating that there was greater slipping deformation because of bolt splicing. The welded joint had no slipping phenomenon.


2014 ◽  
Vol 607 ◽  
pp. 713-716
Author(s):  
Wen Liang Tang ◽  
Chun Yue Huang ◽  
Tian Ming Li ◽  
Ying Liang ◽  
Guo Ji Xiong ◽  
...  

In this paper, ANSYS-LSDYNA simulation software is used to build the three-dimensional finite element model of the ball bond and to get the Von Mises stress. The change of stress about the bump is researched which base on the model in different bonding pressure, bonding power and bonding time. The result show that: The stress increase with bonding pressure increase within a certain bonding pressure range, and then the stress will maintain a table number, however, the stress will continue to increase when the bonding pressure reach a certain value; increasing the bonding power, the area of lager stress will grow; prolonging the bonding time, the stress of the pad will increase with time, but when time increase to a certain value, the stress of the pad will not increase over time.


Author(s):  
Sunil Kumar Sharma ◽  
Jaesun Lee

Railways are very efficient mode of transportation. Speed limits of the railways and loads they carry are increasing rapidly. Due to some advantages, the insulated rail joints are still the part of a rail-track system. However, a high rate of failure of joints puts the railway track at risk. Therefore, a detailed study of these joints is required. In this paper, a three-dimensional finite element model of rail-fishplate joint is created using Abaqus - a finite element method-based software. Stresses in fishplate and bolts due to wheel impact are analysed by coupling implicit and explicit methods. It is found that bolts are a critical part of a joint due to stresses and vibrations to which they are subjected. The large number of stresses and vibration can result into loosening of bolts.


Author(s):  
Cagri Mollamahmutoglu ◽  
Idris Bedirhanoglu

In this study, the performance of a damaged dam was evaluated through a three-dimensional finite element model. The dam is located in Derbendikhan city of Northern Iraq and damaged during a 7.3 magnitude earthquake which was happened 30 kilometers south of Halabja city. Derbendikhan dam which was built between the years 1956-1961 is a clay-core rock fill dam. The damage of the dam was investigated at the site right after the earthquake and some cracks were observed in the main body of the dam. The main goal of this work is to present the results of the survey which was conducted at the site and investigating the damage development mechanism through a realistic three-dimensional finite element model of the dam. As complying with the observations at the site, the finite element analysis has shown that the primary failure mechanism is due to the separation of the core and rock fill sections at the downstream side of the dam.


2012 ◽  
Vol 446-449 ◽  
pp. 2206-2209
Author(s):  
Jin Long Wang

Three-dimensional finite element model of the mine escape capsule is established. With the different values of explosion shock waves, simulation analysis of the entry locker is performed by using ABAQUS. The simulation results indicate that the mine escape capsule is safe and available if the surge pressure of shock waves is less than 3.5Mpa.


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