Buried Pipe Modeling With Initial Imperfections

2004 ◽  
Vol 126 (2) ◽  
pp. 250-257 ◽  
Author(s):  
Junes A. Villarraga ◽  
Jose´ F. Rodrı´guez ◽  
Cora Martı´nez
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Beam Theory ◽  
Element Model ◽  
Problem Formulation ◽  
Element Formulation ◽  
Buried Pipe ◽  
Allowable Limit ◽  
Initial Imperfections ◽  
Nonlinear Elastic

A formulation using the finite element method is presented in this paper to analyze stresses and displacements of underground pipelines with initial imperfections. The formulation includes both thermal expansion of the pipeline and internal pressure. The method is based on large deformation beam theory with the finite element formulation based on Euler-Bernoulli beam elements of constant cross-section. The pipe-soil interaction is modeled as a nonlinear elastic foundation in the problem formulation. The resulting nonlinear finite element model with appropriate boundary conditions is solved using full Newton-Raphson as the iterative procedure. Numerical examples are provided to show the application of the methodology and to demonstrate the effect of the initial imperfections in the stress distribution of a buried pipe. The results show that initial imperfections have a considerable influence on the stress distribution of buried pipelines, leading in some cases to stress levels above the allowable limit established by the design codes. The results also help to identify the critical temperature at which buckling of the buried pipe might occur.

Pontoon Torsional Strength Analysis Related to Ships with Large Deck Openings

1991 ◽  
Vol 35 (04) ◽  
pp. 339-351
Author(s):  
Ivo Senjanovic ◽  
Ying Fan
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Beam Theory ◽  
Element Model ◽  
Middle Part ◽  
Strength Analysis ◽  
Element Formulation ◽  
Dimensional Finite Element ◽  
Torsional Analysis ◽  
Three Dimensional Finite Element

The torsional problem of a pontoon, consisting of channel middle part and rectangular tube peaks, isconsidered within the higher-order beam theory. The cross section and the contour compatibility conditions for assembling of the pontoon parts are investigated. The acceptability of the introduced assumptions is checked by three-dimensional finite-element model analysis. Some deficiencies of the classical beam theory regarding the girder stiffness are noticed. The finite-element formulation to be used for the torsional analysis of the ship's hull with large hatch openings is given.

Research of the Connecting Form about the Spherical Shell and the Nozzle

2011 ◽  
Vol 413 ◽  
pp. 520-523
Author(s):  
Cai Xia Luo
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Finite Element Model ◽  
Spherical Shell ◽  
Maximum Stress ◽  
Peak Stress ◽  
Element Model ◽  
Small Opening ◽  
Large Opening ◽  
Reducing Stress

The Stress Distribution in the Connection of the Spherical Shell and the Opening Nozzle Is Very Complex. Sharp-Angled Transition and Round Transition Are Used Respectively in the Connection in the Light of the Spherical Shell with the Small Opening and the Large One. the Influence of the Two Connecting Forms on Stress Distribution Is Analyzed by Establishing Finite Element Model and Solving it. the Result Shows there Is Obvious Stress Concentration in the Connection. Round Transition Can Reduce the Maximum Stress in Comparison with Sharp-Angled Transition in both Cases of the Small Opening and the Large Opening, Mainly Reducing the Bending Stress and the Peak Stress, but Not the Membrane Stress. the Effect of Round Transition on Reducing Stress Was Not Significant. so Sharp-Angled Transition Should Be Adopted in the Connection when a Finite Element Model Is Built for Simplification in the Future.

scholarly journals A Kollár and Pluzsik anisotropic composite beam theory for arbitrary multicelled cross sections

2016 ◽  
Vol 35 (23) ◽  
pp. 1696-1711 ◽  
Author(s):  
Danilo S Victorazzo ◽  
Andre De Jesus
Keyword(s):  
Finite Element ◽  
Cross Sections ◽  
Composite Beam ◽  
Linear Equations ◽  
Beam Theory ◽  
Element Formulation ◽  
Compliance Matrix ◽  
Asymmetric System ◽  
Anisotropic Composite ◽  
Stiffness Matrices

In this paper we extend Kollár and Pluzsik’s thin-walled anisotropic composite beam theory to include multiple cells with open branches and booms, and present a finite element formulation utilizing the stiffness matrix obtained from this theory. To recover the 4 × 4 compliance matrix of a beam containing N closed cells, we solve an asymmetric system of 2N + 4 linear equations four times with unitary section loads and extract influence coefficients from the calculated strains. Finally, we compare 4 × 4 stiffness matrices of a multicelled beam using this method against matrices obtained using the finite element method to demonstrate accuracy. Similarly to its originating theory, the effects of shear deformation and restrained warping are assumed negligible.

Finite-element modelling of thermo-mechanical stress distribution in laser beam ceramic tile grout sealing process

2006 ◽  
Vol 220 (10) ◽  
pp. 1497-1508 ◽  
Author(s):  
A Liaqat ◽  
S Safdar ◽  
M A Sheikh
Keyword(s):  
Thermal Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Laser Beam ◽  
Mechanical Stress ◽  
Ceramic Tile ◽  
Element Model ◽  
Ceramic Tiles ◽  
Temperature Dependent ◽  
Heat Effects

Laser tile grout sealing is a special process in which voids between the adjoining ceramic tiles are sealed by a laser beam. This process has been developed by Lawrence and Li using a customized grout material and a high power diode laser (HPDL). The process has been optimally carried out at laser powers of 60–120 W and at scanning speeds of 3–15 mm/s. Modelling of the laser tile grout sealing process is a complex task as it involves a moving laser beam and five different materials: glazed enamel, grout material, ceramic tile, epoxy bedding, and ordinary Portland cement substrate. This article presents the finite element model (FEM) of the laser tile grout sealing process. The main aim of this model is to accurately predict the thermo-mechanical stress distribution induced by the HPDL beam in the process. For an accurate representation of the process, the laser was modelled as a moving heat source. A three-dimensional transient thermal analysis was carried out to determine the temperature distribution. Temperature-dependent material properties and latent heat effects, due to melting and solidification of the glazed enamel, were taken into account in the FEM, thereby allowing a more realistic and accurate thermal analysis. The results of the thermal analysis were used as an input for the stress analysis with temperature-dependent mechanical properties. The results obtained from the FEM are compared with the published experimental results.

FINITE ELEMENT ANALYSIS OF A DENTAL IMPLANT

2003 ◽  
Vol 15 (02) ◽  
pp. 82-85 ◽  
Author(s):  
SHYH-CHOUR HUANG ◽  
CHANG-FENG TSAI
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Element Model ◽  
Element Analysis ◽  
3 Dimensional ◽  
Dimensional Finite Element ◽  
The Stability ◽  
Stress Concentration Effect ◽  
Implant System

This paper presents results from using a 3-dimensional finite element model to assess the stress distribution in the bone, in the implant and in the abutment as a function of the implant's diameter and length. Increasing implant diameter and length increases the stability of the implant system. By using a finite element analysis, we show that implant length does not decrease the stress distribution of either the implant or the bone. Alternatively, however implant diameter increases reduce the stresses. For the latter case, the contact area between implant and bone is increased thus the stress concentration effect is decreased. Also, with increased implant diameter the bone loss is decreased and as a consequence the success rate is improved.

Finite Element Formulation and Vibration Frequency Analysis of a Fluid Filled Pipe

2005 ◽  
Author(s):  
Yi Jia ◽  
Reinaldo E. Madeira ◽  
Frederick Just-Agosto
Keyword(s):  
Finite Element ◽  
Coriolis Force ◽  
Frequency Analysis ◽  
Cross Sections ◽  
Vibration Frequency ◽  
Dynamic Performance ◽  
Element Model ◽  
Piping System ◽  
Element Formulation ◽  
Variable Cross

This paper presents the formulation of a finite element model and vibration frequency analysis of a fluid filled pipe having variable cross sections. The finite element method with consideration of Coriolis force developed in [1] was adopted for frequency analysis of a pipe in this study. The stiffness matrix, the c-matrix (Coriolis force) and mass (for dynamic analysis) matrix that contain all parameters of the fluids properties and flow conditions have been developed. The numerical model was employed to simulate the dynamic performance of the piping system with the specific configurations for an application. A critical relationship between the natural frequencies and pipe geometry has been established. The results of frequencies analysis of the piping system gave us an insight whether a resonance frequency might occur.

A finite element model to study the effect of porosity location on the elastic modulus of a cantilever beam

2019 ◽  
Vol 43 (4) ◽  
pp. 443-453
Author(s):  
Stephen M. Handrigan ◽  
Sam Nakhla
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Focused Ion Beam ◽  
Mechanical Response ◽  
Ion Beam ◽  
Three Dimensional ◽  
Beam Theory ◽  
Element Model ◽  
Fe Model ◽  
Three Dimensional Finite Element

An investigation to determine the effect of porosity concentration and location on elastic modulus is performed. Due to advancements in testing methods, the manufacturing and testing of microbeams to obtain mechanical response is possible through the use of focused ion beam technology. Meanwhile, rigorous analysis is required to enable accurate extraction of the elastic modulus from test data. First, a one-dimensional investigation with beam theory, Euler–Bernoulli and Timoshenko, was performed to estimate the modulus based on load-deflection curve. Second, a three-dimensional finite element (FE) model in Abaqus was developed to identify the effect of porosity concentration. Furthermore, the current work provided an accurate procedure to enable accurate extraction of the elastic modulus from load-deflection data. The use of macromodels such as beam theory and three-dimensional FE model enabled enhanced understanding of the effect of porosity on modulus.

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