Is it Possible to Derive the Dresdner Correction Formula Using a Finite Element Program?

2021 ◽  
Author(s):  
Peter Janknecht
Keyword(s):  
Finite Element ◽  
Intraocular Pressure ◽  
Open Source Software ◽  
Corneal Thickness ◽  
Element Analysis ◽  
Finite Element Program ◽  
Correction Formula ◽  
Finite Element Software ◽  
Element Program ◽  
Geometrical Data

Abstract Introduction The aim was to construct a model cornea by CAD and finite element software to find out how the intraocular pressure compares to the forces for applanation at the outside of the model cornea. These data were to be compared to the Dresdner correction formula. Thereby, it was possible to find out whether the model was plausible and to find hints as to why a correction for how the intraocular pressure depends on the corneal thickness is necessary at all. Methods Using the open-source software FreeCad and geometrical data for the cornea of the literature, an average cornea was constructed. On this average cornea, a finite element analysis was performed using the free software z88aurora. The intraocular pressure was measured by applanation of the outer cornea. The necessary forces were analysed. Results In this model, the intraocular pressure had to be corrected depending on the corneal thickness. The correction factor was kmean; finite elements = 19.17 – 0.0334*corneal thickness. The necessary correction did not exclusively depend on the relation between the endothelial area and the area of the outer cornea: for this relation alone the correction would have been karea-relation = 1.0361 – 0.0006*corneal thickness. Discussion The model correction formula was close to the Dresdner formula. The relation between endothelial area and the area of the outer cornea could only explain about half of the necessary correction.

Finite Element Analysis on the Deformation of Energy-Saving Wire-Mesh Frame Wallboard

2014 ◽  
Vol 501-504 ◽  
pp. 731-735
Author(s):  
Li Zhang ◽  
Kang Li
Keyword(s):  
Finite Element ◽  
Energy Saving ◽  
Theoretical Basis ◽  
Steel Wire ◽  
Wire Mesh ◽  
Design Parameters ◽  
Element Analysis ◽  
Finite Element Program ◽  
Element Program ◽  
Influence Degree

This paper analyzes the influence degree of related design parameters of wire-mesh frame wallboard on deformation through finite element program, providing theoretical basis for the design and test of steel wire rack energy-saving wallboard.

The Finite Element Analysis of Dynamic Interaction of High-Speed Shinkansen, the Rail, and Bridge

1993 ◽  
Author(s):  
Makoto Tanabe ◽  
Hajime Wakui ◽  
Nobuyuki Matsumoto
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
High Speed ◽  
Response Analysis ◽  
Element Formulation ◽  
Element Analysis ◽  
Finite Element Program ◽  
The Finite Element Analysis ◽  
Element Program ◽  
The Impact

Abstract A finite element formulation to solve the dynamic behavior of high-speed Shinkansen cars, rail, and bridge is given. A mechanical model to express the interaction between wheel and rail is described, in which the impact of the rail on the flange of wheel is also considered. The bridge is modeled by using various finite elements such as shell, beam, solid, spring, and mass. The equations of motions of bridge and Shinkansen cars are solved under the constitutive and constraint equations to express the interaction between rail and wheel. Numerical method based on a modal transformation to get the dynamic response effectively is discussed. A finite element program for the dynamic response analysis of Shinkansen cars, rail, and bridge at the high-speed running has been developed. Numerical examples are also demonstrated.

Risk Analysis for the Construction Phases of Long-Span CFST Arch Bridge Based on Finite Element Analysis

2011 ◽  
Vol 225-226 ◽  
pp. 823-826
Author(s):  
Yu Feng Zhang ◽  
Guo Fu Sun
Keyword(s):  
Finite Element ◽  
Risk Analysis ◽  
Limit State ◽  
Ultimate Limit State ◽  
Element Analysis ◽  
Nonlinear Buckling ◽  
Finite Element Program ◽  
Arch Bridge ◽  
Cfst Arch Bridge ◽  
Element Program

As a part of virtual simulation of construction processes, this paper deals with the quantitative risk analysis for the construction phases of the CFST arch bridge. The main objectives of the study are to evaluate the risks by considering an ultimate limit state for the fracture of cable wires and to evaluate the risks for a limit state for the erection control during construction stages. Many researches have been evaluated the safety of constructed bridges, the uncertainties of construction phases have been ignored. This paper adopts the 3D finite element program ANSYS to establish the space model of CFST Arch Bridge, and to calculate the linear, the geometrical nonlinear and the double nonlinear buckling safety factors under the six different lode cases. Then the bridge’s risks are evaluated according to the results calculated which provide a reference for design of similar project.

A Nonlinear and Time Dependent Finite Element Analysis of Solder Joints in Surface Mounted Components Under Thermal Cycling

1991 ◽  
Vol 226 ◽  
Author(s):  
Yi-Hsin Pao ◽  
Kuan-Luen Chen ◽  
An-Yu Kuo
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Cycling ◽  
Solder Joints ◽  
Free Edge ◽  
Time Dependent ◽  
Element Analysis ◽  
Finite Element Program ◽  
Element Program ◽  
Peel Stress

AbstractA nonlinear and time dependent finite element analysis was performed on two surface mounted electronic devices subjected to thermal cycling. Constitutive equations accounting for both plasticity and creep for 37Pb/63Sn and 90Pb/10Sn solders were assumed and implemented in a finite element program ABAQUS with the aid of a user subroutine. The FE results of 37Pb/63Sn solder joints were in reasonably good agreement with the experimental data by Hall [19]. In the case of 9OPb/1OSn solder in a multilayered transistor stack, the FE results showed the existence of strong peel stress near the free edge of the joint, in addition to the anticipated shear stress. The effect of such peel stress on the crack initiation and growth as a result of thermal cycling was discussed, together with the singular behavior of both shear and peel stresses near the free edge.

Buckling and layer failure of composite laminated cylinders subjected to hydrostatic pressure

2017 ◽  
Vol 24 (3) ◽  
pp. 415-422 ◽  
Author(s):  
Ke Chun Shen ◽  
Guang Pan ◽  
JiangFeng Lu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Hydrostatic Pressure ◽  
Failure Criteria ◽  
Underwater Vehicle ◽  
Element Analysis ◽  
Finite Element Program ◽  
Failure Characteristics ◽  
Element Program ◽  
Critical Buckling Pressure

AbstractThe buckling and layer failure characteristics of composite laminated cylinders subjected to hydrostatic pressure were investigated through finite element analysis for underwater vehicle application. The Tsai-Wu failure criteria were used as the failure criteria for the buckling analysis. A sensitivity analysis was conducted to research the influence of the number of elements on the critical buckling pressure. ANSYS, a finite element program, successfully predicted the buckling pressure with 5.3–27.8% (linear) and 0.3–22.5% (nonlinear) deviation from experimental results. The analysis results showed that the cylinders can carry more pressure after a slight decrease in pressure and recovery of the supporting load. For layer failure analysis, it was found that the failure that occurred in the 0° layer was more serious than that in the 90° layer within the neighboring layers at the inner layers (nos. 1–7) and outer layers (nos. 8–24).

Nonlinear Response and Failure of Steel Elbows Under In-Plane Bending and Pressure

2003 ◽  
Vol 125 (4) ◽  
pp. 393-402 ◽  
Author(s):  
S. A. Karamanos ◽  
E. Giakoumatos ◽  
A. M. Gresnigt
Keyword(s):  
Finite Element ◽  
Local Buckling ◽  
Shell Element ◽  
General Purpose ◽  
Element Analysis ◽  
Cross Sectional ◽  
Finite Element Program ◽  
Special Cases ◽  
Element Program ◽  
Plane Bending

The paper investigates the response of elbows under in-plane bending and pressure, through nonlinear finite element tools, supported by experimental results from real-scale tests. The finite element analysis is mainly based on a nonlinear three-node “tube element,” capable of describing elbow deformation in a rigorous manner, considering geometric and material nonlinearities. Furthermore, a nonlinear shell element from a general-purpose finite element program is employed in some special cases. Numerical results are compared with experimental data from steel elbow specimens. The comparison allows the investigation of important issues regarding deformation and ultimate capacity of elbows, with emphasis on relatively thin-walled elbows. The results demonstrate the effects of pressure and the influence of straight pipe segments. Finally, using the numerical tools, failure of elbows under bending moments is examined (cross-sectional flattening or local buckling), and reference to experimental observations is made.

Plastic Deformation Theory Application in Finite Element Analysis

2012 ◽  
Vol 594-597 ◽  
pp. 2723-2726
Author(s):  
Wen Shan Lin
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Deformation Theory ◽  
Three Dimensional ◽  
Constitutive Laws ◽  
Constitutive Law ◽  
Element Analysis ◽  
Finite Element Program ◽  
Theory Of Plasticity ◽  
Element Program

In the present study, the constitutive law of the deformation theory of plasticity has been derived. And that develop the two-dimensional and three-dimensional finite element program. The results of finite element and analytic of plasticity are compared to verify the derived the constitutive law of the deformation theory and the FEM program. At plastic stage, the constitutive laws of the deformation theory can be expressed as the linear elastic constitutive laws. But, it must be modified by iteration of the secant modulus and the effective Poisson’s ratio. Make it easier to develop finite element program. Finite element solution and analytic solution of plasticity theory comparison show the answers are the same. It shows the derivation of the constitutive law of the deformation theory of plasticity and finite element analysis program is the accuracy.

Finite Element Analysis on the Bearing Capacity of Tube-Plate Joint with Different Width-Thickness Ratio

2012 ◽  
Vol 204-208 ◽  
pp. 1224-1228
Author(s):  
Jun Fen Yang ◽  
Yi Liang Peng ◽  
Xia Bing Wei ◽  
Jin Bo Cui
Keyword(s):  
Experimental Investigation ◽  
Finite Element ◽  
Bearing Capacity ◽  
Steel Tube ◽  
Thickness Ratio ◽  
Deformation Condition ◽  
Tube Plate ◽  
Element Analysis ◽  
Finite Element Program ◽  
Element Program

Tube-plate joint is a frequently-used joint type in steel-tube tower, but the theoretical analysis and experimental investigation on tube-plate joint are absent both at home and abroad. In this paper, the ANSYS finite element program was used to simulate the bearing capacity and deformation condition of tube-plate joint with 1/2-stiffening ring. Eight calculation models were designed, and the width-thickness ratio was changed by changing the width or thickness of stiffening ring. The results indicate that the influence of different width-thickness ratio on tube-plate joint bearing capability is significant. By increasing the width or increasing the thickness of stiffening rings to improve the bearing capacity of the joint is a very effective way.

Finite Element Analysis of Grooved Gas Thrust Bearings and Grooved Gas Face Seals

1993 ◽  
Vol 115 (3) ◽  
pp. 348-354 ◽  
Author(s):  
D. Bonneau ◽  
J. Huitric ◽  
B. Tournerie
Keyword(s):  
Finite Element ◽  
Reynolds Equation ◽  
Weak Form ◽  
Oscillating Solution ◽  
Element Analysis ◽  
Finite Element Program ◽  
Thrust Bearings ◽  
Face Seals ◽  
Element Program ◽  
Gas Seals

A finite element method enabling the Reynolds equation solution for any face geometry of gas thrust bearing or of gas seal is presented. Difficulties due to thickness discontinuities are reduced by integration by parts of the terms involving derivatives. The weak form of the finite element Reynolds equation is then solved and the nonlinearity of the equation leads to the use of Newton-Raphson procedure. The process is fast convergent. The problem of oscillating solution is solved by the use of an upwind procedure. Some numerical examples show the accuracy and efficiency of the procedures. It is shown that the developed finite element program provides a numerical tool, more efficient than the method used until now, for the grooved gas seals design.

Finite Element Analysis on Energy Dissipation Ability of Geo-Materials under Impact Load

2012 ◽  
Vol 224 ◽  
pp. 381-384
Author(s):  
Wen Bin Liu ◽  
Shu Wang Yan ◽  
Wu Gang Wang ◽  
Miao Yu
Keyword(s):  
Finite Element ◽  
Clay Soil ◽  
Impact Load ◽  
Experiment Data ◽  
Element Analysis ◽  
Finite Element Program ◽  
Calculation Results ◽  
Element Program ◽  
Clay Layers ◽  
Current Code

The non-linear finite element program Ls-DYNA/ANSYS is applied to simulate numerically the capacity for the geo-materials to dissipate the energy induced by the falling objects. The calculation results for the crushed stone coincide well with those recommended by the current Code of《DNV-rp-f107_2010》, which is on the basis of experiment data, implying the feasibility of using this program to estimate the energy dissipating capacity of the geo-materials. Because little research has been performed with clay soil, the program Ls-DYNA/ANSYS is used to predict the energy dissipating capacity of clay layers.

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