VLFEM Analysis of a Two-Dimensional Cochlear Model

1985 ◽  
Vol 52 (4) ◽  
pp. 743-751 ◽  
Author(s):  
C. E. Miller
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Basilar Membrane ◽  
Rate Of Change ◽  
Hybrid Technique ◽  
Two Dimensional ◽  
Arbitrary Boundary ◽  
Reflected Waves ◽  
Full Characterization ◽  
Optimal Mesh

A hybrid technique named here the Very Large Finite Element Method (VLFEM) is developed to analyze a two-dimensional model of the cochlea of the inner ear. In this method, the domain is divided into elements of constant material properties and the exact solution to the model equations obtained in each element. This involves two forms of eigenexpansion, allowing a one-dimensional instead of two-dimensional discretization. The discretization is related to the rate of change of the wavenumber of traveling waves on the elastic partition, producing an optimal mesh spacing. A full characterization of the multiple complex wavenumbers is obtained. The results of this analysis for partition (basilar membrane) amplitude and phase exactly correspond to those from previous finite difference and finite element analyses, but less computing effort is required for the same accuracy of results. Reflected waves, abrupt changes in material properties, and arbitrary boundary conditions pose no difficulties for VLFEM analysis, an advantage over the WKB (or LG) technique used previously on this problem.

Two Dimensional Plane Strain Modeling of Tube Hydroforming

2000 ◽  
Author(s):  
G. T. Kridli ◽  
L. Bao ◽  
P. K. Mallick
Keyword(s):  
Finite Element ◽  
Plane Strain ◽  
Material Properties ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Strain Hardening Exponent ◽  
Hydraulic Pressure ◽  
Two Dimensional ◽  
Dimensional Plane ◽  
Hydroforming Process

Abstract The tube hydroforming process has been used in industry for several years to produce components such as exhaust manifolds. Recent advances in forming machines and machine control systems have allowed for the introduction and the implementation of the process to produce several automotive components, which were originally produced by the stamping process. Components such as side rails, engine cradles, space frames, and several others can be economically produced by tube hydroforming. The process involves forming a straight or a pre-bent tube into a die cavity using internal hydraulic pressure, which may be coupled with controlled axial feeding of the tube. One of the remaining challenges facing product and process engineers in designing hydroformed parts is the lack of an extensive knowledge base of the process. This includes a full understanding of the process mechanics and the effects of the material properties on the quality of the hydroformed product. This paper reports on the results of two dimensional plane strain finite element models of the tube hydroforming process, which were conducted using the commercial finite element code ABAQUS/Standard. The objective of the study is to examine the effects of material properties, die geometry, and frictional characteristics on the selection of the hydroforming process parameters. The paper discusses the effects of the strain-hardening exponent, friction coefficient at the die-workpiece interface, initial tube wall thickness, and die corner radii on the thickness distribution of the hydroformed tube.

A Finite Element Based Procedure for Simulating the Transient Response and Failure of a Two-Dimensional Continuum With Nonlinear Material Characteristics

1973 ◽  
Vol 95 (1) ◽  
pp. 345-352 ◽  
Author(s):  
D. B. Wallace ◽  
A. Seireg
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Impulsive Loading ◽  
Nonlinear Material ◽  
Two Dimensional ◽  
Arbitrary Geometry ◽  
Failure Patterns ◽  
Nonlinear Properties ◽  
Hollow Cylinders ◽  
Failure Theories

This paper presents a finite element based procedure for the analysis and graphic display of the response and failure patterns of a two-dimensional continuum subjected to impulsive loading. Elastic, anelastic, plastic and other nonlinear material properties and failure theories can be incorporated in the analysis. The procedure is illustrated by examples of elastic and anelastic impact of solid and hollow cylinders. The developed technique gives a powerful tool for the evaluation of transient stresses, deformations, yield and fracture modes in two-dimensional continuum with arbitrary geometry and nonlinear properties.

Importance of Material Properties and Porosity of Bone on Mechanical Response of Articular Cartilage in Human Knee Joint—A Two-Dimensional Finite Element Study

2014 ◽  
Vol 136 (12) ◽  
Author(s):  
Mikko S. Venäläinen ◽  
Mika E. Mononen ◽  
Jukka S. Jurvelin ◽  
Juha Töyräs ◽  
Tuomas Virén ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Articular Cartilage ◽  
Knee Joint ◽  
Trabecular Bone ◽  
Material Properties ◽  
Mechanical Response ◽  
Structural Level ◽  
Two Dimensional ◽  
Local Material Properties

Mechanical behavior of bone is determined by the structure and intrinsic, local material properties of the tissue. However, previously presented knee joint models for evaluation of stresses and strains in joints generally consider bones as rigid bodies or linearly elastic solid materials. The aim of this study was to estimate how different structural and mechanical properties of bone affect the mechanical response of articular cartilage within a knee joint. Based on a cadaver knee joint, a two-dimensional (2D) finite element (FE) model of a knee joint including bone, cartilage, and meniscus geometries was constructed. Six different computational models with varying properties for cortical, trabecular, and subchondral bone were created, while the biphasic fibril-reinforced properties of cartilage and menisci were kept unaltered. The simplest model included rigid bones, while the most complex model included specific mechanical properties for different bone structures and anatomically accurate trabecular structure. Models with different porosities of trabecular bone were also constructed. All models were exposed to axial loading of 1.9 times body weight within 0.2 s (mimicking typical maximum knee joint forces during gait) while free varus–valgus rotation was allowed and all other rotations and translations were fixed. As compared to results obtained with the rigid bone model, stresses, strains, and pore pressures observed in cartilage decreased depending on the implemented properties of trabecular bone. Greatest changes in these parameters (up to −51% in maximum principal stresses) were observed when the lowest modulus for trabecular bone (measured at the structural level) was used. By increasing the trabecular bone porosity, stresses and strains were reduced substantially in the lateral tibial cartilage, while they remained relatively constant in the medial tibial plateau. The present results highlight the importance of long bones, in particular, their mechanical properties and porosity, in altering and redistributing forces transmitted through the knee joint.

Analysis of Thermal Stresses and Metal Movement During Welding—Part I: Analytical Study

1975 ◽  
Vol 97 (1) ◽  
pp. 81-84 ◽  
Author(s):  
T. Muraki ◽  
J. J. Bryan ◽  
K. Masubuchi
Keyword(s):  
Finite Element ◽  
Variational Principle ◽  
Material Properties ◽  
Analytical Study ◽  
Thermal Stresses ◽  
Yield Criterion ◽  
Element Formulation ◽  
Two Dimensional ◽  
Butt Welding ◽  
Welding Part

This is the first part of a study of thermal stresses and metal movement during welding. This part discusses analysis of two-dimensional thermal stresses and metal movement during bead-on-plate and butt welding. A finite-element formulation has been derived, based on the variational principle. The formulation includes temperature dependence of material properties as well as the yield criterion.

A Finite Element Study of the Effect of Friction on the Deformations, Forces, Stress Formations, and Energy Losses in a Sliding Contact Between Aluminum and Copper Cylinders

2007 ◽  
Author(s):  
Raghvendra Vijaywargiya ◽  
Itzhak Green
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Copper Alloy ◽  
Sliding Contact ◽  
Energy Losses ◽  
Net Energy ◽  
Two Dimensional ◽  
Element Analysis ◽  
Reaction Forces ◽  
Sliding Distance

This work presents the results of a Finite Element Analysis (FEA) used to simulate two-dimensional (2D) sliding between two interfering elasto-plastic cylinders, one with material properties of a tougher material (copper alloy Glidcop) and the other of a relatively weaker material (aluminum alloy Al 6061-T651). Trends in the deformations, reaction forces, stresses, and net energy losses as a function of sliding distance are established. Results for both frictionless and frictional sliding are presented and comparisons are drawn. The effects of plasticity and friction on energy loss during sliding are isolated.

An Efficient 2-D Finite Element Procedure for Isothermal Phase Changes

1990 ◽  
Vol 112 (4) ◽  
pp. 352-360 ◽  
Author(s):  
S. Chandrasekar ◽  
S. Wang ◽  
H. T. Y. Yang
Keyword(s):  
Finite Element ◽  
Phase Transformation ◽  
Material Properties ◽  
Thermal Stresses ◽  
Phase Changes ◽  
Transient Temperature ◽  
Two Dimensional ◽  
Transient Temperature Distribution ◽  
Finite Element Procedure ◽  
Transformation Problems

An efficient finite element procedure is developed for the temperature and stress analyses of two-dimensional isothermal phase transformation problems such as solidification, melting, and solid-to-solid transformations, etc. This procedure uses adaptive remeshing along the element boundaries to track the discontinuities in the temperature gradient, the enthalpy, and the material properties, which exists across the phase transformation interface. The thermal stresses and the transient temperature distribution developed during solidification are calculated using this for several example problems. They are compared with the numerical and analytical solutions obtained for these problems by earlier investigators in order to demonstrate the efficiency and accuracy of this method, for the analysis of solidification problems, as well as its limitations.

Stress Analysis of Porous Rooted Dental Implants

1976 ◽  
Vol 55 (5) ◽  
pp. 772-777 ◽  
Author(s):  
Allan M. Weinstein ◽  
Jerome J. Klawitter ◽  
Subhash C. Anand ◽  
Richard Schuessler
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Analysis ◽  
Dental Implants ◽  
Plane Stress ◽  
Material Properties ◽  
Mechanical Tests ◽  
Two Dimensional ◽  
Element Analysis ◽  
Selection Of

A two-dimensional plane stress finite element analysis of porous rooted dental implants was performed. The results of this analysis were compared to results obtained from mechanical tests performed on actual implanted specimens. The appropriate selection of interface material properties was shown to be highly significant.

About Verification of Discrete-Continual Finite Element Method for Two-Dimensional Problems of Structural Analysis Part 2: Deep Beam with Piecewise Constant Physical and Geometrical Parameters along Basic Direction

2014 ◽  
Vol 1025-1026 ◽  
pp. 95-103 ◽  
Author(s):  
Pavel A. Akimov ◽  
Marina L. Mozgaleva ◽  
Mojtaba Aslami ◽  
Oleg A. Negrozov
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Structural Analysis ◽  
Rate Of Change ◽  
Geometrical Parameters ◽  
Deep Beam ◽  
Two Dimensional ◽  
Basic Direction ◽  
Piecewise Constant ◽  
Element Method

This paper continues series of papers devoted to verification of discrete-continual finite element method (DCFEM) for two-dimensional problems of structural analysis. Formulation of the problem for deep beam with piecewise constant physical and geometrical parameters along so-called its basic direction, solutions obtained by DCFEM and finite element method (FEM) /with the use of ANSYS Mechanical/, their comparison are presented. It was confirmed that DCFEM is more effective in the most critical, vital, potentially dangerous areas of structure in terms of fracture (areas of the so-called edge effects), where some components of solution are rapidly changing functions and their rate of change in many cases can’t be adequately taken into account by the standard FEM.

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