scholarly journals In-Depth Verification of a Numerical Model for an Axisymmetric RC Dome

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2152
Author(s):  
Przemysław Czumaj ◽  
Sławomir Dudziak ◽  
Zbigniew Kacprzyk
Keyword(s):  
Three Dimensional ◽  
Spatial Models ◽  
Detailed Comparison ◽  
The Finite Element Method ◽  
Robot System ◽  
Engineering Structures ◽  
Computational Analyses ◽  
Computational Systems ◽  
Good Agreement ◽  
Made In

The designers of civil engineering structures often have to face the problem of the reliability of complex computational analyses performed most often with the Finite Element Method (FEM). Any assessment of reliability of such analyses is difficult and can only be approximate. The present paper puts forward a new method of verification and validation of the structural analyses upon an illustrative example of a dome strengthened by circumferential ribs along the upper and lower edges. Four computational systems were used, namely Abaqus, Autodesk Robot, Dlubal RFEM, and FEAS. Different models were also analyzed—two-dimensional (2D) and three-dimensional (3D) ones using continuum, bar, and shell finite elements. The results of the static (with two kinds of load—self-weight and load distributed along the upper ring) and modal analyses are presented. A detailed comparison between the systems’ and models’ predictions was made. In general, the spatial models predicted a less stiff behavior of the analyzed dome than the planar models. The good agreement between different models and systems was obtained for the first natural frequency with axisymmetric eigenmodes (except from the Autodesk Robot system). The presented approach to the verification of complex shell–bar models can be effectively applied by structural designers.

An analytical model of an I-cored coil located above a conductive material with a hole

2018 ◽  
Vol 82 (2) ◽  
pp. 21001
Author(s):  
Grzegorz Tytko ◽  
Leszek Dziczkowski
Keyword(s):  
Test Object ◽  
Middle Layer ◽  
Axially Symmetric ◽  
The Finite Element Method ◽  
Cylindrical Coordinate ◽  
Air Space ◽  
Through Hole ◽  
Tree Method ◽  
Good Agreement ◽  
Made In

The paper examines the problem of an axially symmetric I-cored coil located above a three-layered plate with a hole in the middle layer. A cylindrical coordinate system was applied, wherein the solution domain was truncated in the radial direction. The employment of the truncated region eigenfunction expansion (TREE) method resulted in deriving the final formulas for the change of the coil impedance with regard to the air space, and also pertaining to the test object without a flaw. Formulas for various configurations of the test object, among others for a surface hole, a subsurface hole and a through hole, have been presented. For the purpose of defectoscopy, the influence of the hole in the plate on the impedance components was investigated. The calculations were made in Matlab for frequencies from 100 Hz to 50 kHz. The obtained results were verified using the finite element method (FEM) in Comsol Multiphysics package. A very good agreement was observed in the case of both the resistance and reactance.

Dynamic stress analysis of rotating twisted and tapered blades

1980 ◽  
Vol 15 (3) ◽  
pp. 117-126 ◽  
Author(s):  
V Ramamurti ◽  
S Sreenivasamurthy
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Analysis ◽  
Dynamic Stress ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Extensive Analysis ◽  
Dynamic Stress Analysis ◽  
Skew Angles ◽  
Good Agreement

In this paper the finite element method has been used to determine the stresses and deformations of pre-twisted and tapered blades. Three-dimensional, twenty-noded isoparametric elements have been used for the analysis. Extensive analysis has been done for various pre-twist angles, skew angles, breadth to length ratios, and breadth to thickness ratios of the blades. Experiments were carried out to determine the stresses for the verification of the numerical results and they were found to be in good agreement.

scholarly journals Numerical Modelling of the Three-Dimensional Slamming Problem

2002 ◽  
Author(s):  
Matthieu Tourbier ◽  
Bernard Peseux ◽  
Bundi Donguy ◽  
Laurent Gornet
Keyword(s):  
Finite Element Method ◽  
Experimental Investigation ◽  
Thickness Distribution ◽  
Three Dimensional ◽  
Free Fall ◽  
The Finite Element Method ◽  
Hydrodynamic Problem ◽  
In Series ◽  
Drop Tests ◽  
Good Agreement

This paper deals with the slamming phenomenon for deformable structures. In a first part, a three-dimensional hydrodynamic problem is solved numerically with the Finite Element Method. The results for a rigid body are successfully compared to the analytical solutions. After the numerical analysis, an experimental investigation is presented. It consists in series of free fall drop-tests of rigid, deformable cones shaped models with different deadrise angle and thickness. Distribution of the pressure and its evolution are analyzed. Numerical and experimental results are compared and present good agreement.

The Experimental Study and Numerical Simulation of Turbulent Flow in Pumping Forebay

2009 ◽  
Author(s):  
Chao Liu ◽  
Jiren Zhou ◽  
Li Cheng
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Turbulent Flow ◽  
Three Dimensional ◽  
Computational Results ◽  
Experiment Study ◽  
Study Results ◽  
Measurement Results ◽  
Good Agreement ◽  
Made In

The experiment study was made to optimize the design of a pumping forebay. The Combined-sills were made in the forebay to eliminate the circulation and vortices of the diffusing flow successfully. The Numerical simulation of three-dimensional turbulent flow is applied on the complicate fore-and-aft flow of sills. The computational results are compared with the measurement results of physical model. The calculated results are in good agreement with the experimental data. The flow pattern is obviously improved. The study results have been applied in the project which gives a uniform approach flow to the pumping sump.

On Irregular, Nonlinear Waves in a Spread Sea

1997 ◽  
Vol 119 (1) ◽  
pp. 37-41 ◽  
Author(s):  
P. Jonathan ◽  
P. H. Taylor
Keyword(s):  
Nonlinear Waves ◽  
Three Dimensional ◽  
Nonlinear Effects ◽  
Detailed Comparison ◽  
Offshore Structures ◽  
Sea Surface ◽  
Linear Wave ◽  
Ocean Environment ◽  
Wave Nonlinearity ◽  
Good Agreement

Optimal design and reassessment of offshore structures requires a good understanding of the ocean environment. The motion of the sea surface can be viewed as a three-dimensional, nonlinear stochastic process in time. In order to characterize the wave environment adequately, we need to model its random, nonlinear, and spread nature. In this paper, we address: • the expected shape of a wave near a crest or trough, • the expected shape of the ocean surface at one point, given a crest at a different point, • an efficient method to incorporate nonlinear effects within linear wave simulations, • the magnitude of wave nonlinearity as a function of wave amplitude. Detailed comparison of theory and full-scale offshore measurements at the Shell Expro Tern platform show good agreement.

scholarly journals Charge transport mechanism in dielectrics: drift and diffusion of trapped charge carriers

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Andrey A. Pil’nik ◽  
Andrey A. Chernov ◽  
Damir R. Islamov
Keyword(s):  
Charge Transport ◽  
Three Dimensional ◽  
Continuum Theory ◽  
Theoretical Models ◽  
Charge Carriers ◽  
The Finite Element Method ◽  
Drift Current ◽  
And Diffusion ◽  
Good Agreement ◽  
Trapped Charge

Abstract In this study, we developed a continuum theory of the charge transport in dielectrics by trapped electrons and holes, which takes into account two separate contributions of the current of trapped charge carriers: the drift part and the diffusion one. It was shown that drift current is mostly dominant in the bulk, while the diffusion one reaches significant values near contacts. A comparison with other theoretical models and experiments shows a good agreement. The model can be extended to two- and three-dimensional systems. The developed model, formulated in partial differential equations, can be numerically implemented in the finite element method code.

Experimental Analysis of Orifice Type Thrust Bearing

2006 ◽  
Author(s):  
Charanjeet Kaur Malhi ◽  
Trupti Cherian
Keyword(s):  
Measurement System ◽  
Experimental Analysis ◽  
Thrust Bearing ◽  
Three Dimensional ◽  
Air Bearing ◽  
Frame Design ◽  
Good Repeatability ◽  
Different Diameters ◽  
Good Agreement ◽  
Made In

A single pad thrust bearing with central orifice restrictor, was fabricated and tested with a loading frame design for varying loads and supply pressures. One of the objectives of conducting the test was to obtain load verses air-gap curves for different supply pressures. The air bearing was supplied with different diameters of orifice. Another objective was to measure recess pressure at different supply pressures and loads and obtain a three dimensional plot. The recess pressure in the bearing is measured by the Smart Pressure Device. The testing of the thrust bearing enabled to validate the measurement system used. The results obtained were in good agreement with the investigations made in this field by other investigators. The sensor used also showed good repeatability and linearity, which approves its use for the measurement system.

scholarly journals Three-dimensional Finite Element Modelling of the Cylindrical Specimen Upsetting

2018 ◽  
Vol 220 ◽  
pp. 04008 ◽  
Author(s):  
Mikhail V. Murashov ◽  
Andrey V. Vlasov
Keyword(s):  
Finite Element ◽  
Metal Forming ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Numerical Errors ◽  
Finite Element Software ◽  
Dimensional Finite Element ◽  
Calculation Results ◽  
Three Dimensional Finite Element ◽  
Good Agreement

Friction has a substantial influence on the metal forming at upsetting of cylindrical aluminum specimens. The finite element method is often used to investigate this problem. This paper aims to reveal possible numerical errors and obstacles related to the 3D finite element solution of the problem. The calculation results for the proposed numerical 3D-model are compared with the experimental data. The influence of friction is demonstrated and a good agreement on the tool displacement is obtained. The features of the numerical solution of the problem in the ANSYS finite element software are shown.

scholarly journals Analysis of Deformation and Prediction of Cracks in the Cogging Process for Die Steel at Elevated Temperatures

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5589
Author(s):  
Marcin Kukuryk
Keyword(s):  
Elevated Temperatures ◽  
Metal Flow ◽  
Three Dimensional ◽  
Internal Layers ◽  
The Finite Element Method ◽  
Damage Factor ◽  
Die Steel ◽  
Ductile Fractures ◽  
Thermal Phenomena ◽  
Good Agreement

In this paper, an analysis of a three-dimensional state of strain and stress in the case of the hot cogging process of X32CrMoV12-28 die steel with the application of the finite element method is presented. The results of the investigations connected with the simulation of the kinematics of metal flow and thermal phenomena are presented, accompanied by prognosing the formation of ductile fractures in the course of the hot cogging process conducted with the application of three different shape tools and of a proposed deformation criterion of the loss of cohesion. The applied anvils were found to be highly effective in the aspects of distribution of effective strains and stresses, absence of tensile stresses in the axial zones of a forging, and also of a significant thermal stability in the internal layers of a deformed material. The developed course of changes in the deformation of the damage factor in the case of forging in the investigated anvils renders it possible to predict the situation and the phase of deformation in which the loss of cohesion by a deformed material will occur. The comparison between the predicted and the experimental results showed a good agreement.

Comparison of Conventional and Pontic Fixed Partial Dentures Over Implants Using the Finite Element Method: Three-Dimensional Analysis of Cortical and Medullary Bone Stress

2020 ◽  
Vol 46 (3) ◽  
pp. 175-181
Author(s):  
Marcelo Bighetti Toniollo ◽  
Mikaelly dos Santos Sá ◽  
Fernanda Pereira Silva ◽  
Giselle Rodrigues Reis ◽  
Ana Paula Macedo ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Medullary Bone ◽  
Principal Stresses ◽  
Bone Stress ◽  
Bone Damage ◽  
Rehabilitation System ◽  
Minimum Requirements

Rehabilitation with implant prostheses in posterior areas requires the maximum number of possible implants due to the greater masticatory load of the region. However, the necessary minimum requirements are not always present in full. This project analyzed the minimum principal stresses (TMiP, representative of the compressive stress) to the friable structures, specifically the vestibular face of the cortical bone and the vestibular and internal/lingual face of the medullary bone. The experimental groups were as follows: the regular splinted group (GR), with a conventional infrastructure on 3 regular-length Morse taper implants (4 × 11 mm); and the regular pontic group (GP), with a pontic infrastructure on 2 regular-length Morse taper implants (4 × 11 mm). The results showed that the TMiP of the cortical and medullary bones were greater for the GP in regions surrounding the implants (especially in the cervical and apical areas of the same region) but they did not reach bone damage levels, at least under the loads applied in this study. It was concluded that greater stress observed in the GP demonstrates greater fragility with this modality of rehabilitation; this should draw the professional's attention to possible biomechanical implications. Whenever possible, professionals should give preference to use of a greater number of implants in the rehabilitation system, with a focus on preserving the supporting tissue with the generation of less intense stresses.

Sign in / Sign up

Export Citation Format

Share Document