scholarly journals STRESS-STRAIN DISTRIBUTION IN THE MODEL OF RETROCALCANEAL BURSITIS BY USING HEEL-ELEVATION INSOLES

2020 ◽  
pp. 31-39
Author(s):  
Bohdan Gerasimyuk ◽  
Igor Lazarev ◽  
Oleksandr Movchan ◽  
Maksym Skyban
Keyword(s):  
Stance Phase ◽  
Maximum Stress ◽  
Equivalent Stress ◽  
Von Mises Stress ◽  
The Finite Element Method ◽  
Retrocalcaneal Bursitis ◽  
Foot Model ◽  
Retrocalcaneal Bursa ◽  
Von Mises ◽  
Bone Structures

The aim of this study is the analysis of the equivalent stress on the rear foot structures in retrocalcaneal bursitis, when using heel-elevation insoles of different heights (10 mm and 20 mm). Methods – mathematical calculations of the Achilles force required in the heel-off of the gait stance phase in the conditions of lifting the heel by 10 mm and 20 mm. A 3D-simulation foot model with an enlarged retrocalcaneal bursa was created. The analysis was carried out by the finite element method to calculate and study the stress and strain in the rear foot structures. Results. When using a 10.0 mm height heel-elevation insole, the calf muscle strength, which must be applied to the heel-off of the gait stance phase, was 19.0 % less than without support and 26.8 % less in 20.0 mm insole. Accordingly, analyzing the simulation results in terms of von-Mises stress, the maximum stress observed on the Achilles tendon decreases by 20.0 % and by 30.0 %. The total deformations maximum in the model when using heel-elevation insoles decreased up to 18.1 % and they were localized not in the tendon, but in the bone structures of subtalar joint. The maximum values of the total deformation of the model in the case of 10.0 mm and 20.0 mm heel-elevation insoles were 91.67 mm (–20.2 %) and 80.04 mm (–30.3 %), respectively, compared 114.92 mm in the absence of insoles. When using insole with a height of 10.0 mm, the stress in the retrocalcaneal bursa decreased by 20.0 % and was equal to 14.92 MPa compared to 18.66 MPa, and when using a 20.0 mm insoles - by 30.0 %. Conclusions. It was found that when using 10.0–20.0 mm heel-elevation insoles, the stress distribution in the rear foot structures was significantly reduced by an average of 20.0-30.0 % and correlated with the height of the insoles.

Biomechanical Behavior of All-Ceramic Crowns with Variable Thicknesses of Zirconia Frameworks

2016 ◽  
Vol 835 ◽  
pp. 97-102
Author(s):  
Liliana Porojan ◽  
Florin Topală ◽  
Sorin Porojan
Keyword(s):  
Mechanical Behavior ◽  
Equivalent Stress ◽  
The Finite Element Method ◽  
Static Loads ◽  
Biomechanical Behavior ◽  
All Ceramic ◽  
Ceramic Crowns ◽  
Von Mises Equivalent Stress ◽  
Von Mises ◽  
Posterior Restorations

Zirconia is an extremely successful material for prosthetic restorations, offering attractive mechanical and optical properties. It offers several advantages for posterior restorations because it can withstand physiological posterior forces. The aim of the study was to achieve the influence of zirconia framework thickness on the mechanical behavior of all-ceramic crowns using numerical simulation. For the study a premolar was chosen in order to simulate the mechanical behavior in the components of all-ceramic crowns and teeth structures regarding to the zirconia framework thickness. Maximal Von Mises equivalent stress values were recorded in teeth and restorations. Due to the registered maximal stress values it can be concluded that it is indicated to achieve frameworks of at least 0.5 mm thickness in the premolar area. Regarding stress distribution concentration were observed in the veneer around the contact areas with the antagonists, in the framework under the functional cusp and in the oral part overall and in dentin around and under the marginal line, also oral. The biomechanical behavior of all ceramic crowns under static loads can be investigated by the finite element method.

SuperMeshing: A Deep Learning Method for Boosting Mesh Density in Numerical Computation Within 2D Domain

2021 ◽  
Author(s):  
Handing Xu ◽  
Zhenguo Nie ◽  
Qingfeng Xu ◽  
Xinjun Liu
Keyword(s):  
Numerical Computation ◽  
Spatial Resolution ◽  
Maximum Stress ◽  
Linear Mapping ◽  
Stress Fields ◽  
Von Mises Stress ◽  
Full Detail ◽  
Mesh Density ◽  
Novel Method ◽  
Von Mises

Abstract Due to the limit of mesh density, the improvement of the spatial resolution of numerical computation always leads to a decrease in computing efficiency. Aiming at this inability of numerical computation, we propose a novel method for boosting the mesh density in finite element method (FEM) within 2D domain. Based on the von Mises stress fields of 2D plane-strain problems computed by the FEM, this method utilizes a deep neural network named SuperMeshingNet to learn a non-linear mapping from low mesh-density to high mesh-density in stress fields, and realizes the improvement of numerical computation accuracy and efficiency simultaneously. We adopt residual dense blocks into our mesh-density boost model – SuperMeshingNet to extract abundant local features and enhance the prediction capacity. The results indicate that SuperMeshingNet is able to effectively increase the spatial resolution of the von Mises stress fields under the multiple scaling factors: 2X,4X,and8X. Compared with the targets, the relative error of SuperMeshingNet is 2.44%, which shows better performance than the interpolation methods. Besides, SuperMeshingNet reveals an astonishing strength in predicting the maximum stress value. We publicly share our work with full detail of implementation at https://github.com/zhenguonie/2021_SuperMeshing_2D_Plane_Strain.

Improvement Design of Adhesive Layer on Honeycomb Structure for Railway Vehicle System by Uniform Design Method

2020 ◽  
Vol 830 ◽  
pp. 53-58
Author(s):  
Yung Chang Cheng ◽  
Pongsathorn Pornteparak
Keyword(s):  
Design Method ◽  
Uniform Design ◽  
Equivalent Stress ◽  
Adhesive Layer ◽  
Honeycomb Structure ◽  
Von Mises Stress ◽  
Railway Vehicle ◽  
Original Design ◽  
Control Factors ◽  
Von Mises

The purpose of this paper focuses on adhesive layer strength while having a thermal cycling of honeycomb composite sandwich structure by using the uniform design of experiments method improving the von Mises stress of honeycomb structure. Three system parameters of the honeycomb structure are selected as the control factors to be improved. Uniform design of experiment is applied to create a set of simulation experiments. Applying ANSYS/Workbench software, the finite element modelling is investigated and the von Mises stress of the honeycomb structure is calculated under metal-honeycomb core flatwise tensile test. From the numerical results, the best honeycomb structure dimension of all the experiments which causes the smaller von Mises stress is selected as the improved version of design. Finally, the best model of the experiments which causes the minimum equivalent stress is regarded as the improved version of design. Compared with the original design, the result of ASTM C297 improved version is 17.386 MPa, which mean improved 36.28%, ASTM C364 improved version is 19.015 MPa, which mean improved 25.26%, ASTM C365 improved version is 16.86 MPa, which mean improved 12.35%.

scholarly journals Tympanic Membrane Collagen Expression by Dynamically Cultured Human Mesenchymal Stromal Cell/Star-Branched Poly(ε-Caprolactone) Nonwoven Constructs

2020 ◽  
Vol 10 (9) ◽  
pp. 3043
Author(s):  
Stefania Moscato ◽  
Antonella Rocca ◽  
Delfo D’Alessandro ◽  
Dario Puppi ◽  
Vera Gramigna ◽  
...  
Keyword(s):  
Tympanic Membrane ◽  
Maximum Stress ◽  
Element Model ◽  
Von Mises Stress ◽  
Type I ◽  
Collagen Types ◽  
Collagen Expression ◽  
Polymerase Chain ◽  
Von Mises ◽  
Membrane Collagen

The tympanic membrane (TM) primes the sound transmission mechanism due to special fibrous layers mainly of collagens II, III, and IV as a product of TM fibroblasts, while type I is less represented. In this study, human mesenchymal stromal cells (hMSCs) were cultured on star-branched poly(ε-caprolactone) (*PCL)-based nonwovens using a TM bioreactor and proper differentiating factors to induce the expression of the TM collagen types. The cell cultures were carried out for one week under static and dynamic conditions. Reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) were used to assess collagen expression. A Finite Element Model was applied to calculate the stress distribution on the scaffolds under dynamic culture. Nanohydroxyapatite (HA) was used as a filler to change density and tensile strength of *PCL scaffolds. In dynamically cultured *PCL constructs, fibroblast surface marker was overexpressed, and collagen type II was revealed via IHC. Collagen types I, III and IV were also detected. Von Mises stress maps showed that during the bioreactor motion, the maximum stress in *PCL was double that in HA/*PCL scaffolds. By using a *PCL nonwoven scaffold, with suitable physico-mechanical properties, an oscillatory culture, and proper differentiative factors, hMSCs were committed into fibroblast lineage-producing TM-like collagens.

Influence of Internal Stresses on the Stressing of Material in Components Subjected to Rolling-Contact Loads

1984 ◽  
Vol 106 (4) ◽  
pp. 499-504 ◽  
Author(s):  
E. Broszeit ◽  
J. Adelmann ◽  
O. Zwirlein
Keyword(s):  
Half Space ◽  
Stress Level ◽  
Maximum Stress ◽  
Equivalent Stress ◽  
Local Stress ◽  
Rolling Contact ◽  
Internal Stresses ◽  
Contact Loads ◽  
Distortion Energy ◽  
Von Mises

The stressing of a material in concentrated contacts can be calculated using f.e. the equivalent stress hypothesis by Huber, von Mises, Hencky (distortion energy hypothesis). The stress level can be directly related to the local yield properties of the material. For the calculation of the equivalent stress the influence of friction and internal stresses in the material have to be taken into account. The local stress level in the half space strongly depends on friction and internal stresses. It will be demonstrated, that it is necessary to have a look at a greater part of the full half space to find the maximum stress level.

ANALYSIS OF THE MECHANICAL STATE OF THE HUMAN KNEE JOINT WITH DEFECT CARTILAGE IN STANDING

2016 ◽  
Vol 16 (08) ◽  
pp. 1640021 ◽  
Author(s):  
LULU QIU ◽  
XUEMEI MA ◽  
LILAN GAO ◽  
YUTAO MEN ◽  
CHUNQIU ZHANG
Keyword(s):  
Knee Joint ◽  
Weight Bearing ◽  
Von Mises Stress ◽  
The Finite Element Method ◽  
Human Knee ◽  
Femoral Cartilage ◽  
Human Knee Joint ◽  
Increasing Trend ◽  
Lower Limb Movement ◽  
Von Mises

Knee joint is the hub of human lower limb movement and it is also an important weight-bearing joint, which has the characteristics of load-bearing and heavy physical activities. So the knee joint becomes the predilection site of clinical disease. Once people have the cartilage lesions, their daily life will be affected seriously. The simulation of the knee joint lesions could provide help for clinical knee-joint treatment. Based on the complete model of knee joint, this paper use the finite element method to analyze the biomechanical characteristics of the defective knee joint. The results of simulation show that the stress of cartilages when standing on single leg is approximately doubled than that of standing on two legs. When standing on single leg, the 8-mm diameter osteochondral defect in femur cartilage can generate maximal changes in von-mises stress (by 36.74%), while the von-mises stress on tibia cartilage with 8-mm defect increase by 87%. The stress distribution of cartilages is almost the same, there is no obvious stress concentration when in defect. Increasing the defective diameter, femoral cartilage, meniscus and tibial all present an increasing trend towards stress. When increasing the applied load, the stress of the femoral cartilage, the meniscus and the tibial cartilage all increased.

scholarly journals Pengembangan Alat Bantu Arbor untuk Pembuatan Roda Gigi pada Mesin Frais Vertikal

2021 ◽  
Vol 12 (2) ◽  
pp. 287-296
Author(s):  
Widodo Widodo ◽  
◽  
Rahman Hakim
Keyword(s):  
Metal Cutting ◽  
Engine Speed ◽  
Maximum Stress ◽  
Design Method ◽  
Machining Process ◽  
Von Mises Stress ◽  
Von Mises ◽  
Cutting Processes ◽  
Stress Simulation

The machining process is included in the classification of metal cutting processes, which are used to change the shape of metal or non-metallic product by cutting, peeling or separating. One of the machines used in this cutting process is a vertical type milling machine. This machine functions to make a product, one of which was a gear. The supporting equipment needed to make this gear was a vertical arbor tool. The material used in the manufacture of this product was a cast carbon steel type using the design method for manufacturing and assembly (DFMA), which began by examining and identifying needs, conceptualizing and designing products and making these products tailored to the dimensional specifications of standard and common cutter modules in the market. The results of the manufacture of this tool were directly tested for the manufacture of gears of various sizes and produced products whose deviations were within the tolerance of the measuring instrument, namely in the range 0 to 2%. In addition, the von Mises stress simulation at an engine speed of 150 Rpm, 450 Rpm and 750 Rpm and the resulting maximum stress was still below the yield limit, so it was safe to use.

scholarly journals Evaluation of Stress Distribution and Force in External Hexagonal Implant: A 3-D Finite Element Analysis

2021 ◽  
Vol 18 (19) ◽  
pp. 10266
Author(s):  
Vinod Bandela ◽  
Ram Basany ◽  
Anil Kumar Nagarajappa ◽  
Sakeenabi Basha ◽  
Saraswathi Kanaparthi ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Maximum Stress ◽  
Axial Direction ◽  
Von Mises Stress ◽  
P Value ◽  
Implant Surface ◽  
Element Analysis ◽  
Von Mises

Purpose: To analyze the stress distribution and the direction of force in external hexagonal implant with crown in three different angulations. Materials and Methods: A total of 60 samples of geometric models were used to analyze von Mises stress and direction of force with 0-, 5-, and 10-degree lingual tilt. Von Mises stress and force distribution were evaluated at nodes of hard bone, and finite element analysis was performed using ANSYS 12.1 software. For calculating stress distribution and force, we categorized and labeled the groups as Implant A1, Implant A2, and Implant A3, and Implant B1, Implant B2, and Implant B3 with 0-, 5-, and 10-degree lingual inclinations, respectively. Inter- and intra-group comparisons were performed using ANOVA test. A p-value of ≤0.05 was considered statistically significant. Results: In all the three models, overall maximum stress was found in implant model A3 on the implant surface (86.61), and minimum was found on model A1 in hard bone (26.21). In all the three models, the direction of force along three planes was maximum in DX (0.01025) and minimum along DZ (0.002) direction with model B1. Conclusion: Maximum von Mises stress and the direction of force in axial direction was found at the maximum with the implant of 10 degrees angulation. Thus, it was evident that tilting of an implant influences the stress concentration and force in external hex implants.

scholarly journals A Comparative Biomechanical Analysis of Various Rod Configurations Following Anterior Column Realignment and Pedicle Subtraction Osteotomy

Neurospine ◽  
2021 ◽  
Vol 18 (3) ◽  
pp. 587-596
Author(s):  
Muzammil Mumtaz ◽  
Justin Mendoza ◽  
Ardalan Seyed Vosoughi ◽  
Anthony S. Unger ◽  
Vijay K. Goel
Keyword(s):  
Stress Reduction ◽  
Factor Of Safety ◽  
Maximum Stress ◽  
Element Model ◽  
Pedicle Subtraction Osteotomy ◽  
Biomechanical Analysis ◽  
Anterior Column ◽  
Von Mises Stress ◽  
Correction Technique ◽  
Von Mises

Objective: The objective of this study was to compare the biomechanical differences of different rod configurations following anterior column realignment (ACR) and pedicle subtraction osteotomy (PSO) for an optimal correction technique and rod configuration that would minimize the risk of rod failure.Methods: A validated spinopelvic (L1-pelvis) finite element model was used to simulate ACR at the L3–4 level. The ACR procedure was followed by dual-rod fixation, and for 4-rod constructs, either medial/lateral accessory rods (connected to primary rods) or satellite rods (directly connected to ACR level screws). The range of motion (ROM), maximum von Mises stress on the rods, and factor of safety (FOS) were calculated for the ACR models and compared to the existing literature of different PSO rod configurations.Results: All of the 4-rod ACR constructs showed a reduction in ROM and maximum von Mises stress compared to the dual-rod ACR construct. Additionally, all of the 4-rod ACR constructs showed greater percentage reduction in ROM and maximum von Mises stress compared to the PSO 4-rod configurations. The ACR satellite rod construct had the maximum stress reduction i.e., 47.3% compared to dual-rod construct and showed the highest FOS (4.76). These findings are consistent with existing literature that supports the use of satellite rods to reduce the occurrence of rod fracture.Conclusion: Our findings suggest that the ACR satellite rod construct may be the most beneficial in reducing the risk of rod failure compared to all other PSO and ACR constructs.

scholarly journals Contact Stresses in a Fixed-Bearing Total Ankle Replacement

2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0002 ◽  
Author(s):  
Nicoló Martinelli ◽  
Silvia Baretta ◽  
Alberto Bianchi Castagnone Prati ◽  
Francesco Malerba ◽  
Carlo Corrado Bonifacini ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stance Phase ◽  
Gait Cycle ◽  
Contact Stresses ◽  
Von Mises Stress ◽  
Third Generation ◽  
Fixed Bearing ◽  
Element Analysis ◽  
Von Mises

Category: Ankle, Ankle Arthritis, Basic Sciences/Biologics Introduction/Purpose: Third-generation ankle implants with good clinical results continued to increase the popularity of total ankle arthroplasty (TAA) to address end-stage ankle osteoarthritis preserving joint movement. Newer TAA used fixed-bearing designs, with a theoretical increase of contact stresses leading to a higher polyethylene wear. The purpose of this study was to investigate the contact stresses in the polyethylene component of a new third-generation TAA, with a fixed-bearing design, using 3D finite element analysis. Methods: A three-dimensional finite element model was developed based on the Zimmer Trabecular Metal Total Ankle (ZTMTA) and a finite element analysis was employed to evaluate the contact pressure, contact area and Von Mises stress in the polyethylene articular surface in the stance phase of the gait cycle. Results: The peak values were found at the anterior regions of the articulating surface, where reached 19.8 MPa at 40% of gait cycle. The average contact pressure during the stance phase of gait was 6.9 MPa. The maximum von Mises stress of 14.1 MPa in the anterior section was reached at 40% of the gait cycle. For the central section the maximum von Mises stress of 10.8 MPa was reached at 37% of the gait cycle, whereas for posterior section the maximum of 5.4 MPa was reached at the end of the stance phase (60% of the gait cycle). Conclusion: Although, the average von Mises stress was less than 10 MPa, high peak pressure values were recorded. Advanced models to quantitatively estimate the wear are needed to assess polyethylene and metal component survivorship.

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