scholarly journals COMPARATIVE ANALYSIS OF MONOCORTICAL AND BICORTICAL METHODS OF INSTALLING MINI-IMPLANTS

2021 ◽  
pp. 38-40
Author(s):  
O.Yu. Rivis ◽  
V.S. Melnyk ◽  
M.V. Rivis ◽  
K.V. Zombor
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Comparative Analysis ◽  
Cortical Bone ◽  
Bone Tissue ◽  
Orthodontic Treatment ◽  
The Finite Element Method ◽  
Force Load ◽  
Mini Implants ◽  
Element Method

The aim of the study. Carry out a comparative analysis of the support ability of human jaw bone tissue in monocortical and bicortical installation of a mini-implant of own design OMG. Research methods. In order to study biomechanical characteristics of developed OMG mini-implant and bone tissue capacity during monocortical and bicortical installation, the finite element method (MSE) was used. The scheme and finite element 2-D model of bicortical installation of OMG mini-implant (length 8 mm, diameter 1.8 mm) provided full penetration through one layer of cortical bone equal to 1 mm, the entire cancellous bone and immersion in the second layer of cortical bone by 0, 5 mm. No implantation was immersed in the second cortical layer of bone during monocortical installation. A single force load of 1 N was applied in the horizontal direction parallel to the cortical plate of the bone. Results of the study. One of the most important factors leading to the success of the use of a mini-implant is its stability in the process of orthodontic treatment. Quite a high level of failure in the monocortical installation of mini-screws has led to the search for better methods to ensure the stability of their use. This was a bicortical method of fixation, based on the placement of the minig screw in the thickness of the two cortical plates of the jaws. Area for such installation of mini-screws can be a site of a palate and alveolar sprouts at installation of miniimplants through all its thickness. As shown by our data on the use of the finite element method under the force load of the biomechanical system "bone - mini-implant", the stress concentration zone is located in the area of the cortical bone of the jaw. The results of the calculation of the maximum stresses (σmax, MPa) and the maximum possible displacements (umax, mm) of the mini-implant in the biomechanical system "bone - mini-implant" in monocortical installation were, respectively, 8.27 MPa and 0.300 * 10-8 mm and in bicortical installation 6.00 MPa and 0.201 * 10-8 mm. The bicortical method of fixing the mini-implant in the jaw bones significantly increases the ability to resist deformation of this type of biomechanical system under force loads of the mini-implant. In the bicortical method of mini-implant placement, the extreme values of equivalent according to Mises stresses in the upper part of the cortical bone of the jaw are reduced by 27%. This can be explained by a significant increase in the area of contact due to the two layers of the cortical bone of the jaw with the surface of the mini-implant. Conclusion. The bicortical method of installing mini-implants is a more effective and reliable way to provide skeletal support during orthodontic treatment.

Bone tissue loads around titanium femoral implant and coated with porous layer

2018 ◽  
Vol 2 (90) ◽  
pp. 77-84
Author(s):  
G. Bobik ◽  
J. Żmudzki ◽  
K. Majewska
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Porous Material ◽  
Trabecular Bone ◽  
Cortical Bone ◽  
Bone Tissue ◽  
The Finite Element Method ◽  
Porous Shell ◽  
Cementless Implant ◽  
Trabecular Bone Tissue

Purpose: Difference in the mechanical properties of bone and stiffer femoral implant causes bone tissue resorption, which may result in implant loosening and periprosthetic fractures. The introduction of porous material reduces the stiffness of the implant. The aim of the study was to analyse the influence of porous shell of femoral revision implant on bone tissue loading distribution with use the finite element method. Design/methodology/approach: Load transfer in the femur has been investigated using the finite element method (Ansys). Cementless implant models were placed in the anatomical femur model. Femur model included sponge bone and cortical bone. The solid implant was compared with the implant containing porous material in 70% in outer layer with a thickness of 2 mm. Load of 1500 N during gait was simulated. In addition, the forces of the ilio-tibial band and the abductor muscles were implemented, as well as the torque acting on the implant. Findings: Increase of stress for the porous model was found. The underload zones in bone have been reduced. Loading distribution was slightly more favourable, albeit rather in cortical bone. Stress value in cancellous bone around cementless implant margin has increased to a level that is dangerous for bone loss. Stress in the implant was not dangerous for damage. The stress distribution was different in the implant neck zone where the porous shell borne a little less load and high stress was shifted to the stiffer core. Research limitations/implications: Variable conditions for fitting the stem to the bone as well as the friction conditions were not investigated. Practical implications: Stress values in the spongy bone around the insertion edge of the cementless implant are consistent with long-term clinical results of the bone atrophy in 1 and 2 Gruen`s zones around the fully porous implants. Originality/value: The advantage of fully porous coated implant was the decrease of risk of trabecular bone tissue resorption around the implant tip and the increase of risk of trabecular bone tissue resorption around insertion edge of the implant.

Micro FEM Simulations of Single-Cutting-Edge Sawing of Cortical Bone

2013 ◽  
Author(s):  
Ilige S. Hage ◽  
Ramsey F. Hamade
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cortical Bone ◽  
Orthogonal Cutting ◽  
Optical Microscope ◽  
Depth Of Cut ◽  
The Finite Element Method ◽  
Coupled Neural Networks ◽  
Saw Blade ◽  
Element Method

The finite element method at the micro scale (mFEM) has been gaining in popularity to simulate biomechanical effects. In this paper, a 3D mFEM model is developed to simulate sawing of cortical bone under 2D orthogonal cutting conditions. The aim of the research was to develop a predictive model of the sawing forces and to report them as a function of depth of cut. To obtain the micro geometric input, a heterogeneous anisotropic model was created from several images taken via an optical microscope of the cortex of adult mid-diaphysal bovine femur. In order to identify the various regions representing the micro-architecture of cortical bone, such as osteons, Haversian canals, lamellae and lacunae, MATLAB was utilized for intelligent image processing based on pulsed coupled neural networks. After each micro-phase in the image was assigned the proper mechanical properties, these material-tagged micro-features were imported into the finite element method (FEM) solver. Results from the simulation were correlated to cutting force data that was determined experimentally. Experiments were conducted with individual stainless steel saw blade teeth that were removed from a typical surgical saw blade. The teeth were 0.64 mm thick, with a rake and clearance angle of −10 and 60 degrees, respectively. Representative of clinical conditions for power bone sawing, depths of cut per tooth between 2.5 micrometer and 10 micrometer were investigated. The simulated cutting forces from the mFEM model compared favorably to the experimental data.

COMPARATIVE ANALYSIS OF THE SYSTEM APM WINMACHINE AND CAE ABAQUS FOR CALCULATING THE STRENGTH OF A WELDED JOINT

2020 ◽  
Vol 5 ◽  
pp. 28-32
Author(s):  
V.V. LEONTYEV ◽  
E.V. KONDRATOVA ◽  
V.P. KOLOMIYCHENKO
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Comparative Analysis ◽  
Strain State ◽  
Safety Margin ◽  
Operating Conditions ◽  
The Finite Element Method ◽  
Stress Strain ◽  
Stress Strain State ◽  
Element Method

Traditional methods for calculating welded joints are based on approximate methods for determining the forces that occur in the joint. This leads to inaccuracies in the definition of stress. In addition, this approach does not allow obtaining a complete picture of the stress-strain state of the joint. All this leads to the need to increase the coefficient of safety margin and, as a result, to increase the cost of construction. The proposed method of calculating the connection using the finite element method allows us to determine the stresses in all the elements of the connection very accurately. This makes it possible to obtain a reliable picture of the stress-strain state of all elements of the connection. As a result, it is possible to reduce the complexity of creating a compound and its mass. The finite element method should be used for calculating critical connections with complex operating conditions. An example of calculating such a connection is considered. A comparative analysis of the results of calculating the t-joint using the arm Joint module Of the WinMachine arm system and the Abaqus finite element package is performed.

scholarly journals Analysis of vibration of beams with regularly located openings

2021 ◽  
pp. 22-28
Author(s):  
А.И. Притыкин
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Comparative Analysis ◽  
Natural Frequencies ◽  
The Finite Element Method ◽  
Program Complex ◽  
Simply Supported ◽  
Analytical Relations ◽  
Element Method

В справочной литературе содержатся расчетные зависимости для частот свободных колебаний балок со сплошной стенкой, но отсутствуют данные по собственным колебаниям перфорированных балок. В то же время в судостроении и строительной практике широко распространены балки с перфорированной стенкой, содержащей вырезы круглой, овальной и прямоугольной формы. В статье проведен анализ влияния вырезов на частоту свободных колебаний перфорированных свободно опертых балок. При этом первоначально рассматривались балки со сплошной стенкой, а затем балки таких же размеров с вырезами. Для удобства практических вычислений известная зависимость была трансформирована к виду, позволяющему оценить частоту колебаний только по соотношению площадей полки и стенки и габаритным размерам балки без необходимости определения ее момента инерции и погонной массы. Аналогичные зависимости были получены и для перфорированных балок с круглыми и прямоугольными вырезами, в которых дополнительными факторами являлись параметры перфорации: относительная высота вырезов и относительная ширина перемычек. При отсутствии вырезов формулы для перфорированных балоксводятся к формуле для балки со сплошной стенкой.Сравнительный анализ частот проводился путем расчета по аналитическим зависимостям и методом конечных элементов с использованием программного комплекса ANSYS. На основе проведенного анализа сделан вывод, что наличие регулярно расположенных вырезов с высотой, не превышающей рекомендации Морского Регистра РФ, в зависимости от параметров перфорации приводит к разному повышению частот собственных колебаний однопролетных балок, хотя степень их повышения невелика. Предложенные аналитические зависимости для балок разного конструктивного оформления удовлетворительно согласуются с результатами расчетов МКЭ. In manual on the ship structural mechanics the analytical relations for determination of the natural frequencies of the beams with solid web are given, but there are no data about proper vibration of perforated beams. At the same time in shipbuilding and in structural industry the perforated beams with circular, rectangular and oval openings are widely used. In this article the analysis of influence of openings on the natural frequencies of the simply supported perforated beams is performed. Initially it was considered beams with solid web and then beams of the same dimensions with openings. For commodity of practical calculations, the well-known relation was transformed to the form allowing to appreciate frequency of vibration only with knowledge of ratio of areas of shelves and web without necessity of finding their moment of inertia and running mass of beam. Similar relations were obtained for perforated beams with circular and rectangular openings, in which additional arguments were such parameters of perforation as related depth of openings and related width of web-posts. In case of absence of openings, the formulas for perforated beams are reduced to formula for beam with solid web. Comparative analysis was performed by calculations according to analytical relations and with the finite element method using the program complex ANSYS. On base of performed analysis it was made conclusion that existence of regularly located openings with depth not extending recommendations of Russian Maritime Register, in dependence on parameters of perforation brings to different increasing of natural frequencies of vibration of one span beams, although degree of this increasing is not high. Suggested analytical relations for beams of different constructive design are in a good correlation with results obtained by the finite element method.

Comparative analysis of adhesive failure of orthodontic resins: An in vitro mechanical test with the finite element method

2013 ◽  
Vol 2 (2) ◽  
pp. 124
Author(s):  
OrlandoMotohiro Tanaka ◽  
AnaLeticia Rocha Avila ◽  
Ana PaulaGebert de Oliveira Franco ◽  
MildredBallin Hecke ◽  
Marco AntonioAmorin Vasco ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Comparative Analysis ◽  
Mechanical Test ◽  
The Finite Element Method ◽  
Adhesive Failure ◽  
Element Method
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