Embankment on sludge: predicted and observed performances

2007 ◽  
Vol 44 (5) ◽  
pp. 545-563 ◽  
Author(s):  
Tien H Wu ◽  
Steven Z Zhou ◽  
Stephan M Gale
Keyword(s):  
Finite Element ◽  
Water Treatment ◽  
Input Data ◽  
Bayesian Updating ◽  
Full Scale ◽  
The Finite Element Method ◽  
Water Treatment Sludge ◽  
History Of ◽  
Finite Element Prediction ◽  
Test Embankment

The case history of an embankment built over soft water-treatment sludge is presented. To assure that the sludge would consolidate and gain strength as predicted, a test embankment was built. The observed performance of the test embankment was compared with the predicted performance to verify and modify design assumptions. The results were used to design and construct the full-scale embankment. The finite element method and the critical state model were used to predict the performances of the test embankment and the full-scale embankment. Bayesian updating and system identification were used to update the material properties used in the prediction for the test embankment. The updated properties were then used to update the prediction for the test embankment and to predict the performance of the full-scale embankment. These predictions were compared with the observed performances to evaluate the accuracies of the predictions with different input data. Efforts were made to identify factors that cause differences between predicted and measured performances.Key words: Bayesian updating, consolidation, finite-element prediction, shear strength, stability, water-treatment sludge.

Large Deformation Modeling Applied to the Sheet Metal Electromagnetic Forming

2008 ◽  
Author(s):  
C. Dumitras ◽  
I. Cozminca
Keyword(s):  
Finite Element ◽  
Deformation Process ◽  
Electromagnetic Forming ◽  
Stress And Strain ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Strain Fields ◽  
The Finite Element Analysis ◽  
History Of ◽  
Free Bulging

The electromagnetic forming has the advantage of a minimum forming time, but this is a major obstacle in determining the process’s history of the forming workpiece. Both experimental and theoretical known analysis methods for this process give a discret array of data (only for the displacements). One considers it is more adequate to use the finite element method in studying this process. The main advantage of the finite element analysis is given by the fact that it shows the stress and strain fields in a continuous way during the deformation process. Also, it offers a model from which one can predict the final shape of the part and the possible crack zones. One present a compared study of the experimental and the simulated results achieved of the free bulging aluminum specimens by electromagnetic impulses.

Finite element modeling of hexagonal wire reinforced embankment on soft clay

2000 ◽  
Vol 37 (6) ◽  
pp. 1209-1226 ◽  
Author(s):  
D T Bergado ◽  
C Teerawattanasuk ◽  
S Youwai ◽  
P Voottipruex
Keyword(s):  
Finite Element ◽  
Full Scale ◽  
Soil Reinforcement ◽  
Wire Mesh ◽  
Direct Shear ◽  
Full Scale Test ◽  
Element Analysis ◽  
Consolidation Process ◽  
Scale Test ◽  
Test Embankment

A full-scale test embankment was constructed on soft Bangkok clay using hexagonal wire mesh as reinforcement. This paper attempts to simulate the behavior of the full-scale test embankment using the finite element program PLAXIS. The agreement between the finite element results and the field data is quite good. The important considerations for simulating the behavior of the reinforced wall embankment were the method of applying the embankment loading during the construction process, the variation of soil permeability during the consolidation process, and the selection of the appropriate model and properties at the interface between the soil and reinforcement. The increased reinforcement stiffness tends to increase the reinforcement tension and increase the embankment forward rotation. The reinforcement tensions increased with the compression of the underlying soft foundation. The appropriate interface properties between the backfill soil and the hexagonal wire mesh reinforcement corresponding to the interaction mechanism at working stress conditions were dominated by the direct shear mechanism. The direct shear interaction coefficient of 0.9 was used.Key words: soil reinforcement, hexagonal wire mesh, finite element analysis, field embankment.

scholarly journals Locating and Classifying Defects with Artificial Neural Networks

2008 ◽  
Vol 13-14 ◽  
pp. 117-123 ◽  
Author(s):  
A. Luna Avilés ◽  
Luis Héctor Hernández-Gómez ◽  
J.F. Durodola ◽  
G. Urriolagoitia-Calderón ◽  
G. Urriolagoitia-Sosa
Keyword(s):  
Neural Networks ◽  
Finite Element Method ◽  
Finite Element ◽  
Parametric Analysis ◽  
Input Data ◽  
Natural Frequencies ◽  
Synthetic Data ◽  
The Finite Element Method ◽  
Backpropagation Algorithm ◽  
Neuro Fuzzy

Locating defects and classifying them by their size was done with an Adaptive Neuro Fuzzy Procedure (ANFIS). Postulated void of three different sizes (1x1 mm, 2x2 mm and 2x1 mm) were introduced in a bar with and without a notch. The size of a defect and its localization in a bar change its natural frequencies. Accordingly, synthetic data was generated with the finite element method. A parametric analysis was carried out. Only one defect was taken into account and the first five natural frequencies were calculated. 495 cases were evaluated. All the input data was classified in three groups. Each one has 165 cases and corresponds to one of the three defects mentioned above. 395 cases were taken randomly and, with this information, the ANN was trained with the backpropagation algorithm. The accuracy of the results was tested with the 100 cases that were left. This procedure was followed in the cases of the plain bar and a bar with a notch. In the next stage of this work, the ANN output was optimized with ANFIS. The accuracy of the localization and classifications of the defects was improved.

scholarly journals The Timber Floor Seismic Design by Means Finite Element Method

2019 ◽  
Vol 5 (7) ◽  
pp. 1557-1565
Author(s):  
Abdoullah Namdar ◽  
Shan Saimai
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Analysis ◽  
Seismic Design ◽  
Input Data ◽  
Damping Ratio ◽  
Seismic Load ◽  
The Finite Element Method ◽  
Load Response ◽  
Element Method

To improve accuracy results of numerical analysis, the finite element method software needs to use appropriately with considering accurate input data. Among several factors in realistic and economical seismic structural design, the damping ratio needs to be investigated as a calculated and input data in numerical analysis. In the present study, the effect of accurate damping ratio on timber floor seismic design has numerically been examined. The 6 first modes from a series of eigenvalues were selected to calculate natural frequency and damping ratio. The seismic results with and without applied calculated damping ratio were compared. The strain, displacement, and seismic load response are interpreted. The numerical analysis results were showed that the higher nonlinear displacement occurs in timber floor when the damping ratio was modified in numerical modeling. It was found that the floor seismic design is more critical compared to a column in select accurate damping ratio. The damping ratio has highly effect on timber floor seismic design.

Stress Behavior at the Interface Junction of an Elastic Inclusion

2002 ◽  
Vol 69 (6) ◽  
pp. 844-852 ◽  
Author(s):  
Z. Q. Qian ◽  
A. R. Akisanya ◽  
D. S. Thompson
Keyword(s):  
Finite Element ◽  
Elastic Inclusion ◽  
Symmetric Mode ◽  
The Finite Element Method ◽  
Displacement Fields ◽  
Two Phase ◽  
Stress And Displacement Fields ◽  
Higher Order Terms ◽  
The Matrix ◽  
Finite Element Prediction

The stress distribution at the interface junction of an elastic inclusion embedded in a brittle matrix is examined. Solutions are derived for the stress and displacement fields near the junction formed by the intersection of the interfaces between the inclusion and the matrix. The stress field consists of symmetric (mode I) and skew-symmetric (mode II) components. The magnitude of the intensity factor associated with each mode of deformation is determined using a combination of the finite element method and a contour integral. The numerical results of the stresses near the interface junction of two different inclusion geometries show that the asymptotic solutions of the stresses are in agreement with those from the finite element prediction when higher-order terms are considered. The implications of the results for the failure of particle-reinforced and two-phase brittle materials are discussed.

Finite Element Prediction of Grind-Hardening Layer Thickness

2009 ◽  
Vol 416 ◽  
pp. 253-258 ◽  
Author(s):  
Gui Cheng Wang ◽  
Zhong Feng Pan ◽  
Jin Yu Zhang ◽  
Chong Lue Hua ◽  
Ju Dong Liu
Keyword(s):  
Finite Element ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Grinding Force ◽  
Heat Distribution ◽  
The Finite Element Method ◽  
Cutting Depth ◽  
Hardening Process ◽  
Grind Hardening ◽  
Finite Element Prediction

According to the grind-hardening test and using the multiple linear regression analysis, the empirical formula of the tangential grinding force is established in this paper. Combined with the heat distribution coefficient formula of Rowe and Pettit, the thickness of the grind-hardening layer is predicted by using the finite element method under different grinding parameters. It draws the influence law of the grinding speed, cutting depth and feed rate to the thickness of the grind-hardening layer. It provided the basis to the drawing up, the application and the optimization of the grind-hardening process.

scholarly journals On the Importance of Modeling Stent Procedure for Predicting Arterial Mechanics

2012 ◽  
Vol 134 (12) ◽  
Author(s):  
Shijia Zhao ◽  
Linxia Gu ◽  
Stacey R. Froemming
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
High Stress ◽  
Strain History ◽  
The Finite Element Method ◽  
Arterial Mechanics ◽  
History Of ◽  
Stent Diameter ◽  
The Impact ◽  
Stenting Procedure

The stent-artery interactions have been increasingly studied using the finite element method for better understanding of the biomechanical environment changes on the artery and its implications. However, the deployment of balloon-expandable stents was generally simplified without considering the balloon-stent interactions, the initial crimping process of the stent, its overexpansion routinely used in the clinical practice, or its recoil process. In this work, the stenting procedure was mimicked by incorporating all the above-mentioned simplifications. The impact of various simplifications on the stent-induced arterial stresses was systematically investigated. The plastic strain history of stent and its resulted geometrical variations, as well as arterial mechanics were quantified and compared. Results showed the model without considering the stent crimping process underestimating the minimum stent diameter by 17.2%, and overestimating the maximum radial recoil by 144%. It was also suggested that overexpansion resulted in a larger stent diameter, but a greater radial recoil ratio and larger intimal area with high stress were also obtained along with the increase in degree of overexpansion.

Finite Element Evaluation of the State of Cure in a Tire

1991 ◽  
Vol 19 (4) ◽  
pp. 178-212 ◽  
Author(s):  
W. J. Toth ◽  
J. P. Chang ◽  
C. Zanichelli
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boundary Conditions ◽  
The State ◽  
Temperature History ◽  
The Finite Element Method ◽  
Variable Boundary ◽  
Rubber Compounds ◽  
History Of ◽  
Element Method

Abstract Curing is one of the most important steps in the tire manufacturing process. During this process, a green tire is formed to the desired shape and the compound is converted to a strong, elastic material to meet tire performance needs. The process of curing, commonly called vulcanization, is usually accomplished under pressure and an elevated temperature provided by the mold. The curing process is energy-consuming and has a strong effect on material properties. To attain an optimal state of cure for different compounds of various dimensions at minimal capital and energy costs requires proper evaluation of the state of cure in a tire. Various numerical models have been proposed to determine the state of cure of rubber compounds in molds. Their applications are limited to simple geometry and boundary conditions. For a tire, which has complex shape and variable boundary conditions, the finite element method appears to be an ideal candidate because of its versatility. In this paper, a commercial finite element code, ABAQUS, is used to determine the temperature history of a tire in the curing press. In order to evaluate the state of cure throughout a tire, a user subroutine, HETVAL, is implemented. In the subroutine, the state of cure is determined based on the temperature history using a selected kinetic model, whose cure rate parameters are obtained from moving die rheometer (MDR) measurements. The heat generation due to chemical reaction is also included. The evaluation of the state of cure using the finite element method is benchmarked using a number of rubber compounds with simple geometries and boundary conditions. Both isothermal and nonisothermal conditions are tested. The predicted temperature history of a tire is then verified by the temperature history obtained from the thermocouples embedded in the tire. Parametric studies are carried out to evaluate the effect of various temperature histories on the state of cure in a tire. The results are used to shorten the curing cycle.

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