scholarly journals Seepage Analysis in Short Embankments Using Developing a Metaheuristic Method Based on Governing Equations

2020 ◽  
Vol 10 (5) ◽  
pp. 1761 ◽  
Author(s):  
Dongchun Tang ◽  
Behrouz Gordan ◽  
Mohammadreza Koopialipoor ◽  
Danial Jahed Armaghani ◽  
Reza Tarinejad ◽  
...  
Keyword(s):  
Governing Equations ◽  
Seepage Analysis ◽  
Seepage Rate ◽  
Rate Analysis ◽  
Seepage Problem ◽  
Proposed Model ◽  
Intelligent Models ◽  
High Flexibility ◽  
Mathematical Relationships ◽  
Earth Fill

Seepage is one of the most challenging issues in some procedures such as design, construction, and operation of embankment or earth fill dams. The purpose of this research is to develop a new solution based on governing equations to solve the seepage problem in an effective way. Therefore, by implementing the equations in the programming environment, more than 24,000 models were designed to be applicable to different conditions. Input data included different parameters such as slopes in upstream and downstream, embankment width, soil permeability coefficient, height, and freeboard. With the use of this big data, a new process was developed to provide simple mathematical models for the seepage rate analysis. The study first used intelligent models to simulate the seepage behavior. Finally, the accuracy of the models was optimized using a new metaheuristic algorithm. This led to the ultimate flexibility of the final model presented as a new solution capable of evaluating different conditions. Finally, using the best model, new mathematical relationships were developed based on this methodology. This new solution can be used as a proper alternative to the governing equations of seepage rate estimation. Another advantage of the proposed model is its high flexibility that can be well applied to engineering design in this field, which was not possible using the initial equations.

scholarly journals Stability Improvement Method for Embankment Dam with Respect to Conduit Cracks

2022 ◽  
Vol 12 (2) ◽  
pp. 567
Author(s):  
Young-Hak Lee ◽  
Jung-Hyun Ryu ◽  
Joon Heo ◽  
Jae-Woong Shim ◽  
Dal-Won Lee
Keyword(s):  
Large Scale ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Three Dimensional ◽  
Internal Erosion ◽  
Scale Model ◽  
Seepage Analysis ◽  
Large Scale Model ◽  
Proposed Model ◽  
Improvement Method

In recent years, as the number of reservoir embankments constructed has increased, embankment failures due to cracks in aging conduits have also increased. In this study, a crack in a conduit was modeled based on the current conduit design model, and the risk of internal erosion was analyzed using a large-scale model test and three-dimensional deformation–seepage analysis. The results show that when cracks existed in the conduit, soil erosion and cavitation occurred near the crack area, which made the conduit extremely vulnerable to internal erosion. Herein, a model is proposed that can reduce internal erosion by applying a layer of sand and geotextiles on the upper part of the conduit located close to the downstream slope. In the proposed model, only partial erosion occurred inside the conduit, and no cavitation appeared near the crack in the conduit. The results suggest that internal erosion can be suppressed when the water pressure acting intensively on the crack in the conduit is dispersed by the drainage layer. To validate these results, the pore water pressure, seepage line, and hydraulic gradient were investigated to confirm the erosion phenomenon and reinforcement effect.

Pulsar Detection for Wavelets SODA and Regularized Fuzzy Neural Networks Based on Andneuron and Robust Activation Function

2019 ◽  
Vol 28 (01) ◽  
pp. 1950003 ◽  
Author(s):  
Paulo Vitor de Campos Souza ◽  
Luiz Carlos Bambirra Torres ◽  
Augusto Junio Guimarães ◽  
Vanessa Souza Araujo
Keyword(s):  
Neural Networks ◽  
Large Scale ◽  
Activation Function ◽  
Fuzzy Neural Networks ◽  
Activation Functions ◽  
Large Scale Problems ◽  
Proposed Model ◽  
Fuzzy Neural ◽  
Learning Machine ◽  
Intelligent Models

The use of intelligent models may be slow because of the number of samples involved in the problem. The identification of pulsars (stars that emit Earth-catchable signals) involves collecting thousands of signals by professionals of astronomy and their identification may be hampered by the nature of the problem, which requires many dimensions and samples to be analyzed. This paper proposes the use of hybrid models based on concepts of regularized fuzzy neural networks that use the representativeness of input data to define the groupings that make up the neurons of the initial layers of the model. The andneurons are used to aggregate the neurons of the first layer and can create fuzzy rules. The training uses fast extreme learning machine concepts to generate the weights of neurons that use robust activation functions to perform pattern classification. To solve large-scale problems involving the nature of pulsar detection problems, the model proposes a fast and highly accurate approach to address complex issues. In the execution of the tests with the proposed model, experiments were conducted explanation in two databases of pulsars, and the results prove the viability of the fast and interpretable approach in identifying such involved stars.

Transient Response of Inductrack Systems for Maglev Transport: Part II—Solution and Dynamic Analysis

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Ruiyang Wang ◽  
Bingen Yang
Keyword(s):  
Steady State ◽  
Dynamic Analysis ◽  
Transient Response ◽  
Numerical Procedure ◽  
Steady State Response ◽  
Governing Equations ◽  
Transient Model ◽  
State Response ◽  
Proposed Model ◽  
Non Linear

Abstract In Part I of this two-part paper, a new benchmark transient model of Inductrack systems is developed. In this Part II, the proposed model, which is governed by a set of non-linear integro-differential governing equations, is used to predict the dynamic response of Inductrack systems. In the development, a state-space representation of the non-linear governing equations is established and a numerical procedure with a specific moving circuit window for transient solutions is designed. The dynamic analysis of Inductrack systems with the proposed model has two major tasks. First, the proposed model is validated through comparison with the noted steady-state results in the literature. Second, the transient response of an Inductrack system is simulated and analyzed in several typical dynamic scenarios. The steady-state response results predicted by the new model agree with those obtained in the previous studies. On the other hand, the transient response simulation results reveal that an ideal steady-state response can hardly exist in those investigated dynamic scenarios. It is believed that the newly developed transient model provides a useful tool for dynamic analysis of Inductrack systems and for in-depth understanding of the complicated electro-magneto-mechanical interactions in this type of dynamic systems.

Modeling of Human Lower Extremity Musculo-Skeletal Structure Using Bond Graph Approach

2007 ◽  
Author(s):  
Ali Selk Ghafari ◽  
Ali Meghdari ◽  
Gholam Reza Vossoughi
Keyword(s):  
Sagittal Plane ◽  
Equations Of Motion ◽  
Bond Graph ◽  
Skeletal Structure ◽  
Governing Equations ◽  
Straight Line ◽  
Proposed Model ◽  
In Series ◽  
Muscular Function ◽  
Mechanical Linkage

A vector bond graph approach for dynamic modeling of human musculo-skeletal system is addressed in this article. In the proposed model, human body is modeled as a ten-segment, nine degree of freedom, mechanical linkage, actuated by ten muscles in sagittal plane. The head, arm and torso (HAT) are modeled as a single rigid body. Interaction of the feet with the ground is modeled using a spring-damper unit placed under the sole of each foot. The path of each muscle is represented by a straight line. Each actuator is modeled as a three-element, Hill-type muscle in series with tendon. The governing equations of motion generated by the proposed method are equivalent to those developed with more traditional techniques. However the models can be more easily used in conjunction with control models of neuro-muscular function for the simulation of overall dynamic motor performance. In the proposed structure, segments can be easily added or removed. Such a model may have applications in clinical diagnosis and modeling of paraplegic patients during robotic-assisted walking.

Analysis of Degenerate Bifurcation in Machining Using a Nonlinear Model

2001 ◽  
Author(s):  
M. S. Fofana ◽  
Satish Bukkapatnam
Keyword(s):  
Differential Equations ◽  
Degrees Of Freedom ◽  
Nonlinear Effects ◽  
Governing Equations ◽  
Bifurcation Theorem ◽  
Orthogonal Machining ◽  
Proposed Model ◽  
Nonlinear Delay Differential Equations ◽  
Delay Differential ◽  
Centre Manifold Theorem

Abstract We present a two degrees of freedom model of machining dynamics that compactly captures the nonlinear effects of regeneration, tool wear and plowing under orthogonal machining. Extensive simulation experiments show that the solutions to the governing equations of the model bear distinct similarities to signals from our earlier experiments, as reflected by both visual state portraits as well as the values of the quantifiers of a steady state dynamic system. Governing equations of the model lead to nonlinear delay differential equations, which we reduce to ordinary differential equations using Hopf bifurcation theorem and centre manifold theorem. Despite the ongoing efforts by the authors of this paper to quantify the simulations results analytically and experimentally, we strongly believe that our proposed model will be found to be amenable for studying and analyzing bifurcations that can lead to chatter in machining.

scholarly journals Experimental and Numerical Analysis for Earth-Fill Dam Seepage

2020 ◽  
Vol 12 (6) ◽  
pp. 2490 ◽  
Author(s):  
Ahmed Mohammed Sami Al-Janabi ◽  
Abdul Halim Ghazali ◽  
Yousry Mahmoud Ghazaw ◽  
Haitham Abdulmohsin Afan ◽  
Nadhir Al-Ansari ◽  
...  
Keyword(s):  
Physical Model ◽  
Numerical Models ◽  
Seepage Flow ◽  
Water Levels ◽  
The Body ◽  
Silty Sand ◽  
Internal Erosion ◽  
Dam Failure ◽  
Seepage Analysis ◽  
Earth Fill

Earth-fill dams are the most common types of dam and the most economical choice. However, they are more vulnerable to internal erosion and piping due to seepage problems that are the main causes of dam failure. In this study, the seepage through earth-fill dams was investigated using physical, mathematical, and numerical models. Results from the three methods revealed that both mathematical calculations using L. Casagrande solutions and the SEEP/W numerical model have a plotted seepage line compatible with the observed seepage line in the physical model. However, when the seepage flow intersected the downstream slope and when piping took place, the use of SEEP/W to calculate the flow rate became useless as it was unable to calculate the volume of water flow in pipes. This was revealed by the big difference in results between physical and numerical models in the first physical model, while the results were compatible in the second physical model when the seepage line stayed within the body of the dam and low compacted soil was adopted. Seepage analysis for seven different configurations of an earth-fill dam was conducted using the SEEP/W model at normal and maximum water levels to find the most appropriate configuration among them. The seven dam configurations consisted of four homogenous dams and three zoned dams. Seepage analysis revealed that if sufficient quantity of silty sand soil is available around the proposed dam location, a homogenous earth-fill dam with a medium drain length of 0.5 m thickness is the best design configuration. Otherwise, a zoned earth-fill dam with a central core and 1:0.5 Horizontal to Vertical ratio (H:V) is preferred.

Semi-Analytical Model to Predict the Elastic Post-buckling Response of Axially Compressed Cylindrical Shells with Tailored Distributed Stiffness

2021 ◽  
pp. 1-29
Author(s):  
Ali Imani Azad ◽  
Rigoberto Burgueño
Keyword(s):  
Analytical Model ◽  
Local Buckling ◽  
Radial Deformation ◽  
Governing Equations ◽  
Radial Functions ◽  
Nonlinear Springs ◽  
Proposed Model ◽  
Post Buckling ◽  
3D Printed ◽  
Axial Response

Abstract This study introduces an approximate analytical model to predict the post-buckling response of cylinders with tailored nonuniform distributed stiffness. The shell's wall thickness, and thus its stiffness, is tailored so as to obtain multiple controlled elastic local buckling events when the cylinder is subjected to uniform axial compression. The proposed model treats cylinder segments of different stiffness as individual panels and combines their response by considering them as connected linear or nonlinear springs. The governing equations for the panels are formulated using von Karman's theory and solved by Galerkin's approximate method for a predefined radial deformation. Radial deformation functions are used to improve the model's accuracy and results show that the model's accuracy increases significantly with the number of considered radial functions. The model's predicted axial response for different cylinders are compared to results from experiments on 3D printed samples. Results indicate that this model accurately predicts the order of the buckling events while the buckling forces from the model are higher than those measured experimentally.

Numerical Simulation of 2D Hydraulic Jump Flow in a Vertical Plane

2012 ◽  
Vol 482-484 ◽  
pp. 16-20
Author(s):  
Wen Li Wei ◽  
X.J Zhao ◽  
Y. L Liu
Keyword(s):  
Free Surface ◽  
Hydraulic Jump ◽  
Flow Model ◽  
Vertical Plane ◽  
Surface Profile ◽  
Governing Equations ◽  
Proposed Model ◽  
2D Flow ◽  
Time Changes ◽  
Volume Method

This paper was concerned with a vertical two-dimensional (2D) flow model with free surface. The water governing equations were discretized with finite difference method. The function of volume method was employed to track the moving free surface. The model was used to predict the characteristics of hydraulic jump flow in a 2D vertical plane. The surface profile and time averaged velocity were calculated, which shows the proposed model can be capable of capturing sharp water and gas interface configuration as time changes.

Modeling of the Two-Phase Closed Thermosyphon

1987 ◽  
Vol 109 (3) ◽  
pp. 722-730 ◽  
Author(s):  
J. G. Reed ◽  
C. L. Tien
Keyword(s):  
Steady State ◽  
Analysis Tool ◽  
Governing Equations ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Heat Transfer Coefficients ◽  
Proposed Model ◽  
The Times ◽  
Steady State Solutions ◽  
Liquid And Vapor Phases

A comprehensive model is developed to predict the steady-state and transient performance of the two-phase closed thermosyphon. One-dimensional governing equations for the liquid and vapor phases are developed using available correlations to specify the shear stress and heat transfer coefficients. Steady-state solutions agree well with thermosyphon flooding data from several sources and with film thickness data obtained in the present investigation. While no data are available with which to compare the transient analysis, the results indicate that, for most systems, the governing time scale for system transients is the film residence time, which is typically much longer than the times required for viscous and thermal diffusion through the film. The proposed model offers a versatile and comprehensive analysis tool which is relatively simple.

scholarly journals A Study on Neutral-Point Potential in Three-Level NPC Converters

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3367 ◽  
Author(s):  
Maosong Zhang ◽  
Ying Cui ◽  
Qunjing Wang ◽  
Jun Tao ◽  
Xiuqin Wang ◽  
...  
Keyword(s):  
Neutral Point ◽  
Parametric Perturbation ◽  
Midpoint Potential ◽  
Mathematical Expressions ◽  
Proposed Model ◽  
Zero Sequence ◽  
Simulation And Experiment ◽  
Four Quadrant ◽  
Zero Sequence Voltage ◽  
Mathematical Relationships

This paper proposes an accurate mathematical model of three-level neutral-point-clamped (NPC) converters that can accurately represent the midpoint potential drift of the DC link with parameter perturbation. The mathematical relationships between the fluctuation in neutral-point voltage, the parametric perturbation, and the capacitance error are obtained as mathematical expressions in this model. The expressions can be used to quantitatively analyze the reason for the neutral-point voltage imbalance and balancing effect based on a zero-sequence voltage injection. The injected zero-sequence voltage, which can be used to balance the DC-side voltages with the combined action of active current, can be easily obtained from the proposed model. A balancing control under four-quadrant operation modes is proposed by considering the active current to verify the effectiveness of this model. Both the simulation and experiment results validate the excellent performance of the proposed model compared to the conventional model.

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