scholarly journals Von Mises stresses on Mushroom-loop archwires for incisor retraction: a numerical study

2020 ◽  
Vol 25 (4) ◽  
pp. 44-50
Author(s):  
Marcelo do Amaral Ferreira ◽  
Fábio Rodrigo Mandello Rodrigues ◽  
Marco Antônio Luersen ◽  
Paulo César Borges ◽  
Ravindra Nanda ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Cross Section ◽  
Small Area ◽  
Numerical Study ◽  
Linear Analysis ◽  
Finite Element Code ◽  
Incisor Retraction ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Ansys Workbench

ABSTRACT Objective: To perform a numerical simulation using FEM to study the von Mises stresses on Mushroom archwires. Methods: Mushroom archwires made of titanium-molybdenum alloy with 0.017 x 0.025-in cross-section were used in this study. A YS of 1240 MPa and a Young’s modulus of 69 GPa were adopted. The archwire was modeled in Autodesk Inventor software and its behavior was simulated using the finite element code Ansys Workbench (Swanson Analysis Systems, Houston, Pennsylvania, USA). A large displacement simulation was used for non-linear analysis. The archwires were deformed in their extremities with 0° and 45°, and activated by their vertical extremities separated at 4.0 or 5.0 mm. Results: Tensions revealed a maximum of 1158 MPa at the whole part of the loop at 5.0mm of activation, except in a very small area situated at the top of the loop, in which a maximum of 1324 Mpa was found. Conclusions: Mushroom loops are capable to produce tension levels in an elastic range and could be safely activated up to 5.0mm.

Experimental and Numerical Study of Performance Behavior of Triangular Seal Under High Hydraulic Pressure

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
Bruno R. Mose ◽  
Hyun-Seok Lim ◽  
Dong-Kil Shin
Keyword(s):  
Numerical Simulation ◽  
Cross Section ◽  
Numerical Study ◽  
Hydraulic Pressure ◽  
Element Analysis ◽  
Rocket Propulsion ◽  
Fringe Patterns ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Performance Behavior

In this paper, a seal with triangular cross section was proposed and its performance behavior under compression and various hydraulic pressures was analyzed through experimental and numerical methods. The seal was designed to have a 90 deg corner located near the extrusion gap while hydraulic pressure was applied at an inclination. With this design, it was found that even at hydraulic pressures of up to 18 MPa, the seal offered good fluid tight sealing capabilities without indications of extrusion failures. Such high pressure offers new possibilities for successful application of the seal in aircraft and rocket propulsion equipment. Moreover, the resistance of the seal against leakages was assured because measured contact stresses were greater than applied pressures. A numerical simulation through finite element analysis (FEA) showed that tilting of the delta ring even at angles of ±5 deg did not have any effect on the Von Mises stresses. The FEA results also demonstrated that the deformations and fringe patterns of delta ring were similar to the experimental results.

A Feasibility Investigation on Improving Structural Integrity of Thermoelectric Modules With Varying Geometry

2012 ◽  
Author(s):  
Ugur Erturun ◽  
Karla Mossi
Keyword(s):  
Power Generation ◽  
Material Properties ◽  
Thermal Stresses ◽  
Structural Integrity ◽  
Temperature Dependent ◽  
Thermoelectric Modules ◽  
Geometry Model ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Ansys Workbench

This study investigates the feasibility of improving the structural integrity of thermoelectric modules (TEMs) with varying geometry. For this purpose, six different TEM models with various thermoelectric leg geometries were designed and modeled in order to perform a thermal stress FEA using ANSYS Workbench. Temperature dependent material properties were used since some properties such as coefficients of thermal expansion change with temperature. Significant decrease in thermal stresses and leg deformations were observed with some models. Particularly, the cylindrical TE leg geometry model has approximately 54% lower Von Mises stresses (294MPa) and 13% lower TE leg deformations (3.9μm) than those of the typical TE leg geometry model (635MPa and 4.5μm). Power generation analyses of the models were performed to evaluate the effect of new TE leg geometries on the performance. TEM model with cylindrical TE leg geometry has the highest power generation (29.3mW) among all the models.

scholarly journals Finite Element Analysis and Investigation on Spinning of Quadrilateral Parts with Hollow Cross-Sections Based on Hypocycloid Theory

2020 ◽  
Vol 10 (23) ◽  
pp. 8588
Author(s):  
Xibin Ou ◽  
Xianyong Zhu ◽  
Peng Gu ◽  
Baichao Wang ◽  
Jing Li ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
High Efficiency ◽  
Circular Cross Section ◽  
Forming Process ◽  
Element Analysis ◽  
Spinning Process ◽  
Specific Geometry ◽  
Von Mises ◽  
Von Mises Stresses

This paper presents research on a new high-efficiency, non-circular spinning method based on hypocycloid theory. The trajectory of the roller during the forming process was derived, and the non-circular spinning process was simulated in ABAQUS 2016/Explicit. The distribution of von Mises stresses and equivalent plastic strains after each spinning pass were analyzed. The spinning quality was also investigated. This research proves the feasibility of spinning the workpieces of a non-circular cross-section using hypocycloid theory. This new non-circular spinning method can be used in practice to produce workpieces with a specific geometry and to increase the rotational speed of the workpiece from 60–240 rpm to 600 rpm, thereby improving the efficiency by around 2.5 times while maintaining acceptable forming quality.

Mixing Performance of Different Serpentine Microchannels

2007 ◽  
Author(s):  
C. Nonino ◽  
S. Savino ◽  
S. Del Giudice
Keyword(s):  
Cross Section ◽  
Molecular Diffusion ◽  
Numerical Study ◽  
Reynolds Numbers ◽  
Channel Length ◽  
Mixing Enhancement ◽  
Finite Element Code ◽  
Mixing Performance ◽  
Pure Diffusion ◽  
Model Equations

The results of a comparative numerical study aimed at assessing the mixing performance of planar zig-zag, curvilinear and square-wave microchannels of square cross-section is presented in the paper. To evaluate the mixing enhancement characteristics of each geometry, suitable mixing indices are computed at different axial locations of a single repetitive module of each microchannel when this is fed with two equal streams of fluid having the same thermophysical properties, but different solute concentrations. To separate the effects of the geometry from those of molecular diffusion, entrance flow and channel length, the mixing by pure diffusion in straight microchannels of the same length is also evaluated for comparison. Reynolds numbers in the range from 5 to 150 are considered, while the Pe´clet number is held constant and equal to 2500. All the numerical simulations are carried out using an in-house finite element code for the solution of all model equations.

A comparative numerical study to compute ocular injury in boxing

2019 ◽  
Vol 234 (2) ◽  
pp. 125-135
Author(s):  
Reza Razaghi ◽  
Hasan Biglari
Keyword(s):  
Finite Element ◽  
Optic Nerve ◽  
Numerical Study ◽  
Vitreous Body ◽  
Ocular Injury ◽  
Eye Injuries ◽  
Ocular Injuries ◽  
Von Mises ◽  
Von Mises Stresses ◽  
The Impact

Sport is responsible for between 25% and 40% of all eye injuries. Trauma is integrated to the nature of the sport, especially boxing, which is considered a high-risk sport for ocular injuries. Boxing not only brings about injury to the external side of the eye, but in nearly one third of cases, the intraocular components of the eye are also damaged, followed by serious visual acuity complications. However, so far there is a paucity of knowledge on the ocular injury as a result of a strong hook to the face during boxing. This study was, therefore, aimed to perform a dynamic finite element simulation to calculate the stresses and deformations to the components of the eye (i.e. the cornea, aqueous body, iris, ciliary body, vitreous body, sclera, retina, and optic nerve) as a consequence of a hook to the zygomatic and frontal skull bones of a boxer. To do that, well-verified finite element models of the human skull, eye, and punch developed by the current authors were employed to simulate the traumatic model of the skull. The resulting von Mises stresses and deformations in each component of the eye were calculated and compared. The results revealed higher stresses in the components of the eye as a result of a frontal impact compared to that of the zygomatic one. The concentration of the von Mises stresses in the eye components was mostly located in the lateral circumference of the globe. Regardless of the impact sites, the muscle experienced severe damage while the cornea, as the most anterior, and optic nerve, as the most posterior components of the eye, stayed safe with trivial amounts of stress and deformation. These results have implications not only for understanding the possible ocular injuries from a hook but also for providing comprehensive information to medical experts regarding the types of ocular injuries which may occur during boxing.

scholarly journals Research: Design and Analysis of a Low-Stiffness Porous Hip Stem

2017 ◽  
Vol 51 (6) ◽  
pp. 474-482
Author(s):  
Ibrahim Eldesouky ◽  
Hassan El-Hofy ◽  
Ola Harrysson
Keyword(s):  
Mechanical Properties ◽  
Bone Ingrowth ◽  
Numerical Study ◽  
Stress Shielding ◽  
Tissue Reaction ◽  
Adverse Tissue Reaction ◽  
Von Mises ◽  
Tissue Reactions ◽  
Von Mises Stresses ◽  
Minimum Safety Factor

Abstract Two major problems are associated with total hip replacement: 1) stress shielding and 2) the adverse tissue reaction to certain elements of the implant material. In this regard, a porous implant provides lower stiffness and vacancies for bone ingrowth, making it more suitable for the human bone compared with a solid stem. Moreover, second-generation titanium biomedical alloys, such as TNZT (Ti35Nb7Zr5Ta) and TMZF (Ti12Mo6Zr2Fe), have been introduced to prevent the adverse tissue reactions related to aluminum and vanadium elements of the popular Ti6Al4V alloy. In the current work, an analysis was performed based on uniaxial compression testing of cubic Ti6Al4V structures of different porosities to predict the governing equations that relate the relative density of the structure to the mechanical properties of the structure according to the Gibson-Ashby model. A numerical study was conducted to evaluate the change in stress distribution obtained by incorporating the new titanium alloys in porous hip stem implants. Implants modeled with the mechanical properties of TNZT and TMZF showed a minimum safety factor of 1.69 and 3.02, respectively, with respect to the yield strength. The results demonstrated an increase in the equivalent von Mises stresses and maximum principal elastic strain up to 7% and 15%, respectively, compared with the porous Ti6Al4V implant and up to 108% and 156%, respectively, compared with the solid Ti6Al4V implant.

scholarly journals Experimental and numerical study on the screw connection strength of bamboo-oriented strand board compared with wood-oriented strand board

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Kaiting Zhang ◽  
Fuli Wang ◽  
Runmin Xu ◽  
Xinhui Fan ◽  
Bin Yan ◽  
...  
Keyword(s):  
Bending Strength ◽  
Oriented Strand Board ◽  
Numerical Study ◽  
Bending Moment ◽  
Experimental Tests ◽  
Stiffness Coefficient ◽  
The Difference ◽  
Strength And Stiffness ◽  
Von Mises ◽  
Von Mises Stresses

AbstractThe utilization of resourceful bamboo can alleviate the wood shortage problem. Bamboo-oriented strand board (BOSB) with the highest utilization of bamboo ratio and excellent mechanical properties was considered as a good engineering and furniture material. The strength of joints affects the safety of BOSB structure. This study aims to investigate the effect of screw spacing on the tensile and compressive stiffness and strength of corner joints from BOSB by experimental method combined with finite element method (FEM) compared with wood-oriented strand board (WOSB). The results showed that (1) the strength and stiffness of the corner joint was significantly affected by the screw spacing, and it affected the compressive strength and stiffness of WOSB more significantly; (2) the bending moment and stiffness coefficient of BOSB compressed joint decreased with the increase of spacing, while that of tensile joint increased first and then decreased, and it reached the maximum value, when the spacing was 48 mm; (3) compared with WOSB joint, BOSB joint had higher strength and stiffness, and the failure of the joint was due to the yielding of self-drilling screws. This was also verified by numerical analysis results; (4) the bending moment of BOSB joints was about 2.5 times that of WOSB joints, while the difference between stiffness coefficient was small; (5) the elastic deformations resulted from experimental tests and FEM are similar. It was shown that when the screw spacing is 48 mm, the Von Mises stresses on the BOSB joint were smaller, and the bending strength and stiffness were larger, which was the most suitable screw spacing.

Boundary element method in numerical study of three-dimensional Stokes flows in channels of arbitrary shape

2012 ◽  
Vol 9 (1) ◽  
pp. 94-97
Author(s):  
Yu.A. Itkulova
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Cross Section ◽  
Numerical Study ◽  
Three Dimensional ◽  
Cylindrical Tube ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Periodic Flows ◽  
Element Method

In the present work creeping three-dimensional flows of a viscous liquid in a cylindrical tube and a channel of variable cross-section are studied. A qualitative triangulation of the surface of a cylindrical tube, a smoothed and experimental channel of a variable cross section is constructed. The problem is solved numerically using boundary element method in several modifications for a periodic and non-periodic flows. The obtained numerical results are compared with the analytical solution for the Poiseuille flow.

Impact of mandibular prognathism on morphology and loadings in temporomandibular joints

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Jingheng Shu ◽  
Quanyi Wang ◽  
Desmond Y.R. Chong ◽  
Zhan Liu
Keyword(s):  
Finite Element Analysis ◽  
Pearson Correlation ◽  
Morphological Parameters ◽  
Element Analysis ◽  
Mandibular Prognathism ◽  
Temporomandibular Joints ◽  
Pearson Correlation Analysis ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Asymptomatic Subjects

AbstractLoadings in temporomandibular joints (TMJs) are essential factors in dysfunction of TMJs, and are barely noticed in treatment of maxillofacial deformity. The only approach, which can access stresses in TMJs, could expend day’s even weeks to complete. The objective of the study was to compare the differences of the morphological and biomechanical characteristics of TMJs between asymptomatic subjects and patients with mandibular prognathism, and to preliminarily analyze the connection between the two kinds of characteristics. Morphological measurements and finite element analysis (FEA) corresponding to the central occlusion were carried out on the models of 13 mandibular prognathism patients and 10 asymptomatic subjects. The results indicated that the joint spaces of the patients were significantly lower than those of the asymptomatic subjects, while the stresses of patients were significantly greater than those of asymptomatic subjects, especially the stresses on discs. The results of Pearson correlation analysis showed that weak or no correlations were found between the von Mises stresses and the joint spaces of asymptomatic subjects, while moderate, even high correlations were found in the patients. Thus, it was shown to be a feasible way to use morphological parameters to predict the internal loads of TMJs.

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