scholarly journals A Parametric Study of Jointed Plain Concrete Pavement Using Finite Element Modeling

2017 ◽  
Vol 11 (11) ◽  
pp. 75
Author(s):  
Monireh Zokaei ◽  
Mansour Fakhri ◽  
Saeed Rahiminezhad
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Thermal Stresses ◽  
Structural Response ◽  
Plain Concrete ◽  
Concrete Pavement ◽  
Model Parameters ◽  
3D Fem ◽  
Element Modeling ◽  
Axle Loads

Concrete pavements face various types of distresses such as longitudinal, transverse, and joint cracking due to traffic loading and thermal stresses. The objective of this investigation was to develop Three-Dimensional Finite-Element Models (3D-FEM) to assess the performance of dowel in Jointed Plain Concrete Pavement (JPCP).Finite-element modeling is a powerful tool that can be used for the simulation of the structural response of pavements under the effects of different loading condition. Most of the previous studies ignored important factors, including the combined effect of dynamic axle loads and thermal gradient. Overcoming the shortcomings of the previous studies, this study investigated the pavement response under the effect of some model parameters. The result of the study was verified by a comparison with field measurements. Results also showed that the combined negative gradient and axle loads located at the transverse joint subject the top of mid-slab, to high tensile stress that may explain the initiation of top-down cracks. These stresses increase under corner loading when the slab length is increased. In general, the study presented that the developed 3D-FEM is suitable for identifying the effect of different design features including pavement geometry, material properties, thermal gradients, and axle load and configuration on the structural response of rigid pavements.

Combining Serial Sectioning, EBSD Analysis, and Image-Based Finite Element Modeling

MRS Bulletin ◽  
2008 ◽  
Vol 33 (6) ◽  
pp. 597-602 ◽  
Author(s):  
G. Spanos ◽  
D.J. Rowenhorst ◽  
A.C. Lewis ◽  
A.B. Geltmacher
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Electron Backscatter Diffraction ◽  
Three Dimensional ◽  
Research Area ◽  
Polycrystalline Materials ◽  
Serial Sectioning ◽  
3D Fem ◽  
Element Modeling ◽  
The Status

AbstractThis article first provides a brief review of the status of the subfield of three-dimensional (3D) materials analyses that combine serial sectioning, electron backscatter diffraction (EBSD), and finite element modeling (FEM) of materials microstructures, with emphasis on initial investigations and how they led to the current state of this research area. The discussions focus on studies of the mechanical properties of polycrystalline materials where 3D reconstructions of the microstructure—including crystallographic orientation information—are used as input into image-based 3D FEM simulations. The authors' recent work on a β-stabilized Ti alloy is utilized for specific examples to illustrate the capabilities of these experimental and modeling techniques, the challenges and the solutions associated with these methods, and the types of results and analyses that can be obtained by the close integration of experiments and simulations.

A Comparative Evaluation of Finite Element Modeling of Creep Deformation of Fuel Channels in CANDU® Nuclear Reactors

2018 ◽  
Author(s):  
F. J. Tallavo ◽  
M. D. Pandey ◽  
M. Jyrkama ◽  
N. C. Christodoulou ◽  
G. A. Bickel ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Creep Deformation ◽  
Nuclear Reactors ◽  
Deformation Analysis ◽  
Control Mechanisms ◽  
3D Fem ◽  
Fem Model ◽  
Fuel Channel ◽  
Element Modeling

A key element of the fuel channel life cycle management in CANDU® nuclear reactors is to prevent contact between the pressure tube (PT) and the calandria tube (CT) in a fuel channel. By preventing PT-CT contact, the development of hydride blisters and delayed hydride cracking of the PT can be avoided. The PT-CT contact is a result of in-reactor deformation due to irradiation induced creep of the fuel channel assembly. Excessive sagging of the PT can also interfere with the free passage of the fuel bundles when the channel is refueled. Contact of the CT with reactor control mechanisms located horizontally between the fuel channels can result from excessive sag of the CT. The prediction of dimensional changes due to in-reactor creep and the time of PT-CT contact is calculated using finite element modeling of the fuel channel with appropriate creep constitutive laws describing PT and CT deformation. The three-dimensional nature of creep deformation of fuel channels can be approximated by a one-dimensional finite element model (1D-FEM), which is a computationally tractable problem. However, the simplifications of a 1D-FEM model come at the expense of loss of prediction accuracy. This paper compares creep deformation analysis of fuel channels using 1D-FEM and 3D-FEM models. The comparison is based on PT and CT sag profiles as well as on PT-CT gap at different time intervals during service of the fuel channel. Results from the comparative analysis show that the 1D-FEM model predicts greater values of PT-CT gap. The difference in gap predicted between both FEM models increases rapidly when the minimum gap is located in the outlet span. At 250,000 equivalent full power hours, the 1D-FEM model overestimate the gap by 1.12 mm with respect to the 3D-FEM model.

Finite Element Modeling for Optimizing Hermetic Package Reliability

1989 ◽  
Vol 111 (4) ◽  
pp. 255-260 ◽  
Author(s):  
J. H. Lau ◽  
L. B. Lian-Mueller
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Optimal Design ◽  
Thermal Behavior ◽  
Finite Element Modeling ◽  
Thermal Stresses ◽  
Finite Element Models ◽  
The Finite Element Method ◽  
Element Modeling ◽  
Package Reliability

The thermal stresses in microwave packages are studied by the finite element method. Emphasis is placed on the effects of material construction and design on the reliability of very small hermetic packages. Three different microwave packages have been designed and six finite element models (two for each design) have been analyzed. To verify the validity of the finite element results, some leak tests have been performed and the results agree with the analytical conclusions. The results presented herein should provide a better understanding of the thermal behavior of hermetic packages and should be useful for their optimal design.

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