International Journal of Mathematics and Computers in Simulation


ISSN: 1998-0159
Volume 12, 2018

Notice: As of 2014 and for the forthcoming years, the publication frequency/periodicity of NAUN Journals is adapted to the 'continuously updated' model. What this means is that instead of being separated into issues, new papers will be added on a continuous basis, allowing a more regular flow and shorter publication times. The papers will appear in reverse order, therefore the most recent one will be on top.

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Volume 12, 2018


Title of the Paper: Effects of Different Crack-Face Boundary Conditions on the Dynamic Intensity Factors in Functionally Graded Piezoelectric Solids

 

Authors: Michael Wunsche, Jan Sladek, Vladimir Sladek, Chuanzeng Zhang

Pages: 111-115

Abstract: Piezoelectric materials have the capability to convert electric energy into mechanical energy and vice versa. Functional gradations of the material properties are getting increasing attention in advanced engineering applications. Accurate and efficient numerical methods are required for the simulation and safety analysis of such structures. In this paper, the transient dynamic analysis of functionally graded piezoelectric composites with cracks is presented. A timedomain boundary element method (BEM) is developed for this purpose. The present BEM uses the collocation method for the spatial discretization of the time-domain boundary integral equations (BIEs), while the convolution quadrature method is applied to the temporal discretization. An iterative solution algorithm is implemented to solve the non-linear semi-permeable electric crack-face boundary condition. The investigated numerical examples indicate a significant influence of the electric crack-face boundary condition, the functionally gradation and the transient dynamic loading on the normalized intensity factors.


Title of the Paper: Applications of the DNS CONV-3D Code for Simulations the Matis-H Experiment

 

Authors: Vladimir V. Chudanov, Anna E. Aksenova, Valerii A. Pervichko

Pages: 105-110

Abstract: In this paper, we present the results of the CONV-3D code application for modeling the Matis-H experiment (Korea) on water coolant flow around the test assembly with different types of grid spacers. A satisfactory coincidence of numerical predictions with the experiment, in particular, on the distribution of average velocity and rms its depending on the coordinate, is demonstrated. The calculations performed allow recommending the use of the CONV-3D code of the DNS class, which has a high predictive capacity, for the calculation coolant flow around the fuel assembly with different types of grid spacers.


Title of the Paper: Evaluation Performance Of Hybrid Localized Multi Kernel SVR in Electrical Load Data Using 4 Different Optimization

 

Authors: Rezzy Eko Caraka, Sakhinah Abu Bakar

Pages: 96-104

Abstract: The main problem using SVR is to find optimal parameter (σ) by using kernel function such as radial basis, polynomial, gaussian and so on. Moreover, we also have to find optimal hyperplane parameter (C and ε). In the heart of statistics methods and data mining, the motivation of Researcher doing this is to minimize time, money and energy in the analysis at the same time the results will be more accurate. The development of such a massive technology and the availability of data is very much making progress and improvement of methods based on data mining. In this paper, we proposed 3 different optimization such as LIBSVM, MOSEK, QUADPROG, SMO applied to Localized Kernel Learning (LKL).


Title of the Paper: Nonlinear Dynamics of Micro-Electromechanic Element

 

Authors: Dmitrii Ju. Skubov, Alexei V. Lukin, Lev V. Shtukin

Pages: 88-95

Abstract: Static and dynamic problems of coupled electro-elasticity are considered for electrostatic (capacitive) transducers used as sensors and actuators based on nano- and microsystem technology in various applications. Above-mentioned problems are analyzed by mathematical apparatus of nonlinear mechanics and bifurcation theory as well as modern numerical methods, including numerical continuation techniques for nonlinear boundary-value problems. Comparative analysis of analytical and numerical methods was per-formed for nonlinear static and dynamic boundary problems of electro-elasticity for nano- and microsystems engineering. Equilibrium forms, their stability and bifurcations were studied for afore-named elastic systems under the influence of electric fields of various configurations.


Title of the Paper: Comparative Study Between IP and Fuzzy-PI Controller in a Speed Control for Doubly Fed Induction Motor

 

Authors: Abderazak Saidi, Farid Naceri

Pages: 74-87

Abstract: This paper presents a comparison between a fuzzy logic controller and a conventional IP controller used for speed control with a direct stator flux orientation control of a doubly fed induction motor. The effectiveness of the proposed control strategy is evaluated under different operating conditions such as of reference speed and for load torque step changes at nominal parameters and in the presence of parameter variation. Simulation results show that the fuzzy logic controller is more robust than a conventional IP controller against parameter variation and uncertainty, and is less sensitive to external load torque disturbance with a fast dynamic response.


Title of the Paper: Time-Delay Systems with Application to Mechanical Engineering Process Dynamics and Control

 

Authors: André A. Keller

Pages: 64-73

Abstract: Time-delay systems with constant or variable delays can take the form of delay differential equations (DDEs) from a mathematical point of view. DDEs combine the continuous aspect of differential equations and sample features of difference equations. Such “mixed difference equations” go back to the astronomer’s three-body problem of Condorcet in 1767. R.E. Bellman & K.L. Cooke published a seminal study on DDEs in the 1960’s. Russian mathematician Komanovskii, Myshlis & Nosov (1999) developed the study of their stability and applications to the industrial problems. Mathematical software packages like Mathematica® and MATLAB® introduced solvers recently for DDEs with constant delays. DDEs are essential for modeling, forecasting, and simulation of complex real-life systems for which delays cannot be neglected. Time-delay systems are applied extensively in various domains of science and industry such as mechanical systems, electrical systems, industrial processes, and biological systems. Some delays are due to inherent properties of a system where the propagation of effects takes time. The necessity of feedback controls to stabilize a system also introduce some inevitable delays. This study introduces this modeling process and analysis using some real-life deterministic applications from mechanical engineering dynamics and control such as with the metal rolling system and machine tool chatter.


Title of the Paper: Introducing Automatic Evaluation in Virtual Laboratories for Control Engineering at University of Extremadura - First Steps

 

Authors: Inés Tejado, Emiliano Pérez, Isaías González, Pilar Merchán, Blas M. Vinagre

Pages: 55-63

Abstract: In the last decades, the academic community has developed a huge variety of interactive resources to support teaching both in the classroom and in the laboratory, especially in engineering degrees. Among them, the use of virtual and remote laboratories (VRLs), which combine features of traditional laboratories with interactive simulations, is essential to students to acquire practical skills, i.e., obtain the technical know-how that will be their most important asset in their professional career. One of the current interests in this field focuses on reducing the assessment workload of the faculty staff. This paper describes the first steps in the introduction of automatic evaluation in virtual laboratories (VLs) built with Easy Java/Javascript Simulations (EJS/EjsS) for automatic control courses in engineering. With the final objective that the students can detect calculation errors, as well as misconceptions related to the theoretical background, two examples of VLs are given to show their utility to validate the student answers in a simple way. For illustration purposes, some exercises are proposed and solved with the VLs developed.


Title of the Paper: Approximate Mathematical Model and Analysis of the Hot Particle Cooling in a Volatile Liquid

 

Authors: Іvan V. Kazachkov

Pages: 49-54

Abstract: The approximate mathematical model for a cooling of the particle in a volatile liquid is developed and analyzed. Despite the precise model is complex and requires the solution of the nonstationary two-phase flow equations with the conjugated heat transfer boundary problem for the particle, vapor, and liquid cooling pool, the considered simple model may be of interest. Vapor is permanently produced and removed from the coolant’s pool. Analysis of the model obtained resulted in some correlations for the three main parameters of the cooling process, which may be used for estimation of the particle’s cooling.


Title of the Paper: Stability and Mean Consistent of Fourier Solutions of Nonlinear Stochastic Heat Equations in 1D

 

Authors: Haziem M. Hazaimeh

Pages: 44-48

Abstract: The main focus of this article is studying the stability of solutions of nonlinear stochastic heat equation and give conclusions in two cases: stability in probability and almost sure exponential stability. Also, We prove that the Fourier coefficient solution is mean consistent. The main tool is the study of related Lyapunov-type functionals. The analysis is carried out by a natural N-dimensional truncation in isometric Hilbert spaces and uniform estimation of moments with respect to N.


Title of the Paper: Blended Wing’ CFD Analysis: Aerodynamic Coefficients

 

Authors: G. Salazar-Jiménez, H. A. López-Aguilar, J. A. Gómez, A. Chazaro-Zaharias, A. Duarte-Moller, A. Pérez-Hernández

Pages: 33-43

Abstract: This document is focused in the analysis of the aerodynamic behavior of the airfoil and wing geometry used in an unmanned aerial vehicle (UAV) named “Cenzontle”, whose operating conditions rank between 300,000 and 400,000 Re. The wing geometry is compound of three sections, a rectangular one in the middle of the wingspan and two changes of trapezoidal geometries at the tips. The wing utilizes the airfoil called Pinefoil, a novel geometry obtained by interpolation of the S1223 and CH10 airfoils. Through Computational Fluid Dynamics (CFD) simulations, the lift (Cl) and drag (Cd) coefficients are estimated as well as the aerodynamic forces on straight and leveled flight in order to calculate the payload of the aircraft. Additionally, the object of study is rotated on its 3 axis, representing the roll, pitch and yaw movements. By applying a statistical analysis of response surface, it is possible to estimate the lift generated while turning the airplane in order to avoid the stall of the wing. The CFD tools represent an accurate option to estimate these parameters with precision.


Title of the Paper: Fractional Model Predictive Controller (FMPC) Design and Analysis for a Robotic System

 

Authors: Abhaya Pal Singh, Himanshu Agrawal, Pallavi Srivastava

Pages: 27-32

Abstract: This paper proposes a Fractional Model Predictive Controller (FMPC) design strategy for missile launching Pads (or Vehicles). The mathematical modeling of launching vehicle is obtained from Euler-Lagrange formulation and expressed in its fractional equivalent model. The model is approximated using Oustaloup-Recursive-Approximation for different fractional values of α. These fractional models are then considered for model predictive control. Using simulation experiment it is observed that the fractional model predictive controller of launching vehicle gives better response as compared to ordinary model predictive control strategy.


Title of the Paper: New Idea of Time and Life Science Data Registration

 

Authors: Andris Buikis, Alberts Aldersons

Pages: 14-26

Abstract: The paper is destined for use in medicine, psychology, in man’s self-development training; breathing technique’s training, in the field of stress resistance, health promotion, strengthening of the capacity for work. We involve new technology for registration of time interval between two consecutive EKG RR intervals (R peaks) or pulse wave peaks, which consist of simultaneous registration of two time intervals: 1) the time between two consecutive R peaks, and 2) time interval from the beginning of registration and beginning of each wholesome R or pulsogram peak. Our new mathematical algorithm allows reconstructing all pulsogram or RR intervalogram, providing full use of time domain and also frequency domain methods.


Title of the Paper: Comparison of Different Approaches to Continuous-Time System Identification from Sampled Data

 

Authors: Martin Tuma, Pavel Jura

Pages: 9-13

Abstract: This article deals with different approaches to continuous-time system identification from sampled data. Continuous-time system identification is important problem in control theory. Continuous time models provide many advantages against discrete time models because of better physical insight into the system properties. The traditional approach with least squares method with state variable filters is presented. Two alternative approaches to continuous-time identification are proposed. The generalized Laguerre functions method and the method based on least squares estimation with numerical solution of differential equation are introduced. These three different approaches to continuous-time system identification from sampled data are compared on the example. It is shown that proposed alternative methods can give better results in terms of relative root mean square error of the outputs of the identified systems than the least squares method with state variable filters.


Title of the Paper: Multiclass SVM Bearing Fault Diagnosis of Induction Motors Using Hilbert Huang Transform

 

Authors: Mohamed Nacer Saadi, Messaoud Boukhenaf, Abdelghani Redjati, Noureddine Guersi

Pages: 1-8

Abstract: Fault detection is a major challenge for asynchronous motor maintenance. Bearing defects are the most important defects that can occur in theseIn this context, we propose a new approach using Hilbert Huang transform-based stator current analysis (HHT) and multi-class support vector (MSVM) machines for the diagnosis of these failures.Experimental data, obtained from the stator current of the asynchronous motor subjected to various loads in the healthy and faulty cases of the bearings, are analyzed and classified. The applied MSVM classifier is able to identify the type of faulty bearing and our experimental results demonstrate the effectiveness of the proposed method.