scholarly journals Numerical Simulations of Viscoelastic Fluid Flows Using a Least-Squares Finite Element Method Based on Von Mises Stress Criteria

2017 ◽  
Vol 7 (3) ◽  
pp. 157-164 ◽  
Author(s):  
Hsueh-Chen Lee ◽  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Simulations ◽  
Least Squares ◽  
Viscoelastic Fluid ◽  
Fluid Flows ◽  
Von Mises Stress ◽  
Von Mises ◽  
Stress Criteria ◽  
Element Method

scholarly journals Finite element analysis of the tibial component alignment in frontal and sagittal plane in total knee arthroplasty

2021 ◽  
Vol 68 (3) ◽  
pp. 374-378
Author(s):  
Roman Popescu ◽  
◽  
Stefan Cristea ◽  
Adrian Marius Pascu ◽  
Valentin Oleksik ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Tibial Component ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
Von Mises Stress ◽  
The Finite Element Method ◽  
Tibial Resection ◽  
Von Mises ◽  
Element Method

Background. This study aims to analyze the tibial component using the finite element method by cutting the tibial in frontal and sagittal planes at an angle between 1.5° (valgus and anterior tilt) and -1.5° (varus and posterior tilt). Methods. This experimental study used the finite element method as an useful tool for simulating the positioning of the tibial component in order to create a personal pre-operative planning. For the finite element method analysis, a geometrical model of a tibia from a cadaver was three – dimensionally scanned and the tibial component, polyethylene and cement, were three-dimensionally shaped in Computer-Aided Design program using material data such as Young modulus (gigapascal – GPa) and the Poisson coefficient. The analysis determined the equivalent von Mises stress, the maximum displacement of the components and the equivalent von Mises deformation. The results showed that equivalent tension and deformation have higher values in the tibia and the polyethylene, which deform faster than cement and the tibial component. In our study, we chose to simulate the tibial resection at a cutting angle ± 1.5° from neutral positioning (which is represented in frontal plane by the perpendicular on the mechanical axis and in sagittal plane by the posterior slope of 7 degree) in frontal and sagittal plane in order to find the minimum threshold from which the tibial component malalignment may begin to determine unfavorable effects. Results. Our results have shown detrimental effects begin to appear for the polyethene component at -1.5° in frontal plane, and the rest of the components at 1.5° in sagittal plane. Conclusion. This finding leads us to propose preoperative planning based on personal calculus of predefined angles, which may show the surgeon the optimal implantation position of the tibial component.

scholarly journals Numerical Investigation of Two-Dimensional Oldroyd-B Fluid Flows Over A Straight Rectangular Domain

2020 ◽  
Vol 12 (3) ◽  
pp. 327-339
Author(s):  
K. M. Helal
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Simulations ◽  
Stress Tensor ◽  
Flow Behavior ◽  
Fluid Flows ◽  
Rectangular Domain ◽  
Two Dimensional ◽  
Extra Stress Tensor ◽  
Element Method

In this paper, non-Newtonian viscoelastic Oldroyd-B fluid flows in two-dimensional rectangular domain is numerically investigated, where the flow between two rigid walls is driven by a pressure difference along -direction (horizontal). The numerical results of the nonlinear system of partial differential equations are obtained by decoupling the system into Navier-Stokes system and tensorial transport equation. Computational Fluid Dynamics (CFD) simulations are done by using the finite element method. The numerical simulations are presented in terms of the contours of velocity, pressure and extra stress tensor. The Hood-Taylor finite element method is used for the approximation of the velocity and the pressure while the discontinuous Galerkin method is used to approximate the stress tensor. All the meshes and simulations are carried out by the general finite element solver FreeFem++, which has been found as a potential tool to provide a reasonably good numerical simulations of complicated flow behavior.

scholarly journals The Mechanical Behavior of Bone Cement in THR in the Presence of Cavities

2014 ◽  
Vol 4 (3) ◽  
pp. 625-630
Author(s):  
A. Benouis ◽  
B. Serier ◽  
B. Bachir Bouiadjra
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Mechanical Behavior ◽  
Bone Cement ◽  
Von Mises Stress ◽  
Lateral Part ◽  
The Finite Element Method ◽  
Breaking Strain ◽  
Von Mises ◽  
Element Method

In this work we analyze three-dimensionally using the finite element method, the level and the Von Mises stress equivalent distribution induced around a cavity and between two cavities located in the proximal and distal bone cement polymethylmethacrylate (PMMA). The effects of the position around two main axes (vertical and horizontal) of the cavity with respect to these axes, of the cavity - cavity interdistance and of the type of loading (static) on the mechanical behavior of cement orthopedic are highlighted. We show that the breaking strain of the cement is largely taken when the cement in its proximal-lateral part contains cavities very close adjacent to each other. This work highlights not only the effect of the density of cavities, in our case simulated by cavity-cavity interdistance, but also the nature of the activity of the patient (patient standing corresponding to static efforts) on the mechanical behavior of cement.

A Study on the Galerkin Least-Squares Method for the Oldroyd-B Model

2018 ◽  
Vol 18 (2) ◽  
pp. 181-198
Author(s):  
Tsu-Fen Chen ◽  
Hyesuk Lee ◽  
Chia-Chen Liu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Error Estimate ◽  
Least Squares ◽  
Viscoelastic Fluid ◽  
Least Squares Method ◽  
A Priori ◽  
Fluid Flows ◽  
Planar Channel ◽  
A Priori Error Estimate

AbstractWe consider a reduced Galerkin least-squares finite element method for the Oldroyd-B model of viscoelastic fluid flows. Model problems considered are the flow past a planar channel and a 4-to-1 contraction problems. An a priori error estimate for the reduced Galerkin least-squares method is derived and numerical results supporting the estimate are presented.

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