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

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.

2020 ◽  
Vol 10 (22) ◽  
pp. 8261
Author(s):  
Ewa Zawiślak ◽  
Anna Olejnik ◽  
Roman Frątczak ◽  
Rafał Nowak

The analysis aimed at studying stresses reduced according to Huber’s hypothesis and displacement patterns at selected sites of the facial skeleton using a tooth-borne appliance in surgically assisted rapid maxillary expansion. Five different variants of osteotomy of the midface and a variant without surgical intervention were compared to determine the best model for making an incision in the maxilla. The finite element analysis (FEA) was used for the study. Five osteotomy variants and a variant without osteotomy were modelled using a tooth-borne appliance on a facial skeleton model of a 23-year-old woman with skeletal malocclusion. The finite element mesh was constructed based on the geometry imported into the ANSYS 15.0 (Swanson Analysis System of USA) software, in which calculations were performed using the finite element analysis. Stress distributions and displacement patterns along the X, Y and Z axes are presented for each osteotomy variant with the expansion of the tooth-borne appliance at a level of 0.5 mm. As a result of the analysis it was found that osteotomy of the palatal suture in conjunction with Le Fort I osteotomy has the biggest impact on the course of maxillary expansion. If no osteotomy is performed, an increase in stresses reduced according to Huber occurs in the entire facial skeleton with a simultaneous absence of maxillary expansion.


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.


2013 ◽  
Vol 442 ◽  
pp. 229-232 ◽  
Author(s):  
Li Mei Wu ◽  
Fei Yang

According to the cutting theory of involute tooth profile, established an exact three-dimensional parametric model by UG. Used ABAQUS to crate finite element model for gear meshing. After simulated the meshing process, discussed the periodicity of the tooth surface contact stress. Based on the result of finite element analysis, made a comparison of the maximum contact stress between finite element solution and Hertz theoretical solution, analyzed the contact stress distribution on tooth width, and researched the effect of friction factor on contact stress. All that provided some theoretical basis for gear contact strength design.


2013 ◽  
Vol 710 ◽  
pp. 243-246
Author(s):  
Xian Hong Yang

The use of Pro/E and their respective advantages ANSYS software product design and engineering analysis to solve the case, first of all in the Pro/E, the completion of three-dimensional helical gear design, and then in the Pro/MECHANICA completed finite element model of helical gear, and then into ANSYS for finite element analysis of bevel gear calculation and simulation, finite element analysis of the final results of optimization design model is presented recommendations for improvement. The product design and engineering analysis method has some reference value in engineering design.


2015 ◽  
Vol 733 ◽  
pp. 591-594
Author(s):  
Yong Zhen Zhu ◽  
Kuo Yang ◽  
Qi Yang ◽  
Yun De Zhao

The CAD software was used to establish 3D model of frame of dump truck, and the finite element model was established through Hyper Mesh. The stress distributions of the frame in vertical accelerating, turning, twisting and climbing conditions were computed through finite element software when the dump truck was loaded 80t. The result is consistent with the actual situation of the frame, which proved that the approach of finite element analysis is feasible. And we proposed the improved method of the frame according to finite element results.


2018 ◽  
Vol 10 (6) ◽  
pp. 168781401877525 ◽  
Author(s):  
Shangjun Ma ◽  
Chenhui Zhang ◽  
Tao Zhang ◽  
Geng Liu ◽  
Shumin Liu

In this article, 3D or three-dimensional finite element analysis is used to simulate and evaluate the load distribution characteristics of a planetary roller screw mechanism under thermo-mechanical coupling. The finite element model takes into account the installation modes of the planetary roller screw mechanism, which is verified by comparison with theoretical models for a certain load magnitude in four installation modes. In addition, the effects of the installation mode, load magnitude, and temperature condition on the load distribution are also systematically analyzed. The numerical results reveal a phenomenon of threads separating from the meshing, which indicates that the influence of thermo-mechanical coupling on the load distribution cannot be ignored. Furthermore, the influence of the installation mode on the screw–roller interface is larger than that on the nut–roller interface. Compared with the screw–roller interface, the temperature difference is one of the main conditions affecting the load distribution of the planetary roller screw mechanism and has a significant effect on the nut–roller interface. In addition, the influences of the screw rotational speed and the load magnitude on the load distribution on the screw–roller interface are larger than those on the nut–roller interface for the four installation modes.


2010 ◽  
Vol 118-120 ◽  
pp. 147-150
Author(s):  
Da Zhao Yu ◽  
Yue Liang Chen ◽  
Yong Gao ◽  
Wen Lin Liu ◽  
Zhong Hu Jia

Three-dimensional finite element model of a cracked bolted joint has been developed in the non-linear finite element code MSC.Marc and attempts were made to validate it by comparing results with those of experiments and other finite element. Issues in modeling the contact between the joint parts, which affect the accuracy and efficiency of the model, were presented. Experimental measurements of load transfer were compared with results from finite element analysis. The results show that three-dimensional finite element model of cracked bolted joint can produce results in close agreement with experiment. Three-dimensional effects such as bolt titling, seconding and through-thickness variations in stress and strain are well represented by such models. Three-dimensional finite element analysis was also used to study the effects of hole mod and crack on the load transfer behaviour of single lap bolted joints. The results show that hole mode has big effect on load transfer of cracked bolted joint. In the whole progress of crack growth, the load transfer through bolt 1 decrease, and almost all of the load duduction of bolt 1 transfer into blot 2 rather than into bolt 3.


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