scholarly journals Numerical simulations of magnetic resonance elastography using finite element analysis with a linear heterogeneous viscoelastic model

2017 ◽  
Vol 21 (1) ◽  
pp. 133-145
Author(s):  
Sunao Tomita ◽  
Hayato Suzuki ◽  
Itsuro Kajiwara ◽  
Gen Nakamura ◽  
Yu Jiang ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Magnetic Resonance ◽  
Numerical Simulations ◽  
Viscoelastic Model ◽  
Magnetic Resonance Elastography ◽  
Element Analysis

scholarly journals Finite Element Analysis of the Nanomechanics of Hard Coatings on a Soft Polymer Substrate by a Spherical Indenter

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Chunlai Tian ◽  
Pengfei Duan
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Viscoelastic Model ◽  
Coating System ◽  
Element Analysis ◽  
Soft Polymer ◽  
Indentation Response

Composite has been widely used in various fields due to its advanced performance. To reveal the relation between the mechanical properties of the composite and that of each individual component, finite element analysis (FEA) has usually been adopted. In this study, in order to predict the mechanical properties of hard coating on a soft polymer, the response of this coating system during nanoindentation was modelled. Various models, such as a viscoelastic model and fitting model, were adopted to analyse the indentation response of this coating system. By varying the substrate properties (i.e., Young’s modulus, viscoelasticity, and Poisson’s ratio), Young’s modulus, energy loss, and the viscoelastic model of the coating system were analysed, and how the mechanical properties of the substrate will affect the indentation response of the coating system was discussed.

Stresses in Teeth and Overlying Crowns

2012 ◽  
Vol 457-458 ◽  
pp. 567-571
Author(s):  
Liliana Sandu ◽  
Florin Topală ◽  
Sorin Porojan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Numerical Simulations ◽  
Experimental Model ◽  
3D Scanning ◽  
Analysis Software ◽  
Element Analysis ◽  
Equivalent Stresses ◽  
Von Mises

A complete cast crown allows the operator to modify axial tooth contour. The margin should be smooth and distinct and its width has to allow adequate bulk of metal at the margin. The objective of this study was to evaluate, by finite element analysis, the influence of different degree of taper and marginal designs for cast crown preparations, on the stress distribution in teeth and crowns. As experimental model an upper first molar was used. The geometry of the intact tooth were obtained by 3D scanning. The tooth preparations and the complete cast crowns were designed. Models were exported in a finite element analysis software for structural simulations. Von Mises equivalent stresses were calculated and their distribution was plotted graphically. Numerical simulations provide a biomechanical explanation for stress distribution in prepared teeth and overlying crowns.

Interpreting Microscopic Magnetic Resonance Elastography Measurements Using Finite Element Analysis

2013 ◽  
Author(s):  
Yifei Liu ◽  
Temel Yasar ◽  
Thomas J. Royston
Keyword(s):  
Finite Element Analysis ◽  
Wave Propagation ◽  
Magnetic Resonance ◽  
Material Parameter ◽  
Shear Stiffness ◽  
Small Dimension ◽  
Magnetic Resonance Elastography ◽  
Element Analysis ◽  
Axisymmetric Shell ◽  
Parameter Values

Microscopic Magnetic Resonance Elastography (μMRE) could be useful in estimating the shear stiffness of biological or other samples of small dimension. In this study, a silicon rubber phantom shell with liquid inside of it was measured using μMRE. A parametric simulation study of a simplified axisymmetric shell model was performed in order to interpret the wave propagation and how it is affected by the material parameter values.

MICRO-CONSTITUENT BASED VISCOELASTIC FINITE ELEMENT ANALYSIS OF BIOLOGICAL CELLS

2010 ◽  
Vol 02 (02) ◽  
pp. 229-249 ◽  
Author(s):  
F. CHENG ◽  
G. U. UNNIKRISHNAN ◽  
J. N. REDDY
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Material Properties ◽  
Reaction Force ◽  
Experimental Studies ◽  
Viscoelastic Model ◽  
Material Model ◽  
Outer Cortex ◽  
Element Analysis ◽  
Actin Cortex

A viscoelastic analysis of the biological cell considering the microcellular material properties is carried out in this work. Three separate regions of the cell: the actin cortex, cytoplasm and nucleus are considered. The outer cortex and cytoplasm are modeled using standard linear viscoelastic model (SLS) and standard neo-Hookean viscoelastic solid, and a linear elastic material model is considered for the nucleus. The effect of the material properties of cytoplasm and actin cortex on the derivable parameters from three major experimental studies of magnetic twisting cytometry (MTC) and atomic force microscopy (AFM) and micropipette aspiration (MPA) are analyzed using the finite element method. The bead center displacement for the MTC, reaction force for AFM, and aspiration length ratio for the MPA are the major quantities derived from the finite element analysis. A number of parametric studies are also conducted and it is observed that SLS and SnHS models predict nearly identical results for the material constants.

Localization of the Shear Zone in Extrusion Processes by Means of Finite Element Analysis

2009 ◽  
Vol 424 ◽  
pp. 221-226 ◽  
Author(s):  
Matthias Kammler
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Simulations ◽  
Shear Zone ◽  
Friction Model ◽  
Microstructure Development ◽  
Element Analysis ◽  
Numerical Investigations ◽  
Dead Metal Zone ◽  
The Dead

A characteristic feature of extrusion processes is the formation of a shear zone, which separates the deformation zone and the dead metal zone [1, 2]. The deformations occurring in the shear zone cause inner separation and welding effects, which are of great importance for the material flow and the microstructure development of the extruded profiles. The material in the dead metal zone is not participating directly in the forming process but the shape of this zone influences eminently the forming zone and thus the forming of the extruded profile. Furthermore the extreme shear deformation causes according to the Hall-Petch relationship a significant grain refinement in these regions of extruded profiles [3, 4]. So the knowledge on the effects in the shear zone during extrusion processes is fundamental for subsequent numerical investigations on the microstructure development for example regarding quenching techniques. The aim of this study is to localize the formation of the shear zone during extrusion processes by means of the finite element analysis. On the basis of the assumption that separation and welding effects take place in the shear zone, numerical investigations were carried out to indicate these microscopic effects on the macroscopic scale. The considered process was the extrusion of a solid round profile of the alloy EN AW 6082 at 450°C with a punch velocity of 10.5 mm/s. For the localization of the shear zone mechanical parameters were chosen for a shear criterion, which are taken from numerical simulations. A user subroutine was implemented into the FE-models in order to evaluate the shear criterion for the localization of the shear zone. According to [5, 6] the friction model used for the numerical simulations has a strong influence on the formation of the shear zone. In this study a combined friction model according to [7] was used.

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