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Keykha A.H.,Islamic Azad University at Zahedan
Steel and Composite Structures | Year: 2017

Steel structures often require strengthening due to the increasing life loads, or repair caused by corrosion or fatigue cracking. Carbon Fiber Reinforced Polymers (CFRP) is one of the materials used to strengthen steel structures. Most studies on strengthening steel structures have been carried out on steel beams and steel columns under centric compression load. No independent article, to the author's knowledge, has studied the effect of CFRP strengthening on steel columns under eccentric compression load, and it seems that there is a lack of understanding on behavior of CFRP strengthening on steel columns under eccentric compression load. However, this study explored the use of adhesively bonded CFRP flexible sheets on retrofitting square hollow section (SHS) steel columns under the eccentric compression load, using numerical investigations. Finite Element Method (FEM) was employed for modeling. To determine ultimate load of SHS steel columns, eight specimens with two types of section (Type A and B), strengthened using CFRP sheets, were analyzed under different coverage lengths, the number of layers, and the location of CFRP composites. Two specimens were analyzed without strengthening (control) to determine the increasing rate of the ultimate load in strengthened steel columns. ANSYS was used to analyze the SHS steel columns. The results showed that the CFRP composite had no similar effect on the slender and stocky SHS steel columns. The results also showed that the coverage length, the number of layers, and the location of CFRP composites were effective in increasing the ultimate load of the SHS steel columns. © 2017 Techno-Press, Ltd.

Soleymani F.,Islamic Azad University at Zahedan
Japan Journal of Industrial and Applied Mathematics | Year: 2013

This paper opens the issue of solving a nonlinear equation by iterative methods in which no derivative is required per iteration. Hence, an optimal class of three-step methods without memory is demonstrated, where each of its elements (methods) requires only four function evaluations per iteration to achieve the eighth order of convergence. In order to verify the effectiveness of the proposed methods, we employ numerical examples. The attained results are consistent with the developed theory. We finally present an algorithm to capture all the real simple solutions of nonlinear functions in an interval. © 2013 The JJIAM Publishing Committee and Springer Japan.

Soleymani F.,Islamic Azad University at Zahedan | Karimi Vanani S.,Islamic Azad University at Zahedan
Computers and Mathematics with Applications | Year: 2011

This paper proposes two classes of three-step without memory iterations based on the well known second-order method of Steffensen. Per computing step, the methods from the developed classes reach the order of convergence eight using only four evaluations, while they are totally free from derivative evaluation. Hence, they agree with the optimality conjecture of KungTraub for providing multi-point iterations without memory. As things develop, numerical examples are employed to support the underlying theory developed for the contributed classes of optimal Steffensen-type eighth-order methods. © 2011 Elsevier Ltd. All rights reserved.

Soleymani F.,Islamic Azad University at Zahedan
Mathematical and Computer Modelling | Year: 2011

It is widely known that when the order of root solvers increases, their accuracy comes up as well. In light of this, most of the researchers in this field of study have tried to increase the order of known schemes for obtaining optimal three-step eighth-order methods in which there are four evaluations per iteration. The aim of this article is to challenge this standpoint when the starting points are in the vicinity of the root, but not so close. Toward this end, a novel method of order six with the same number of evaluations per iteration is suggested and demonstrated while its accuracy is better than the accuracy of optimal eighth-order schemes for such initial guesses. The superiority of the developed technique is confirmed by numerical examples. © 2010 Elsevier Ltd.

Narmashiri K.,Islamic Azad University at Zahedan | Ramli Sulong N.H.,University of Malaya | Jumaat M.Z.,University of Malaya
Construction and Building Materials | Year: 2012

This paper reports the experimental and numerical investigations on the Carbon Fibre Reinforced Polymer (CFRP) failure analysis and structural behaviour of the CFRP flexural strengthened steel I-beams. Understanding the CFRP failure modes is useful to find solutions for preventing or retarding the failures. One non-strengthened control beam and twelve strengthened beams using different types and dimensions of CFRP strips in both experimental test and simulation modelling studies were investigated. In the experimental test, four-point bending method with static gradual loading was applied. To simulate the specimens, the ANSYS software in full three dimensional (3D) modelling case and non-linear analysis method was utilized. The results show the CFRP failure modes used in flexural strengthening of steel I-beams include below point load splitting (BS), below point load debonding (BD), end delamination (EDL), and end debonding (ED). The occurrences and sequences of CFRP failure modes depended on the strengthening schedule. The structural performance of the CFRP strengthened steel beams also varied according to the strengthening specifications investigated in this research. © 2011 Elsevier Ltd. All rights reserved.

Soleymani F.,Islamic Azad University at Zahedan | Stanimirovic P.S.,University of Niš
The Scientific World Journal | Year: 2013

A method with high convergence rate for finding approximate inverses of nonsingular matrices is suggested and established analytically. An extension of the introduced computational scheme to general square matrices is defined. The extended method could be used for finding the Drazin inverse. The application of the scheme on large sparse test matrices alongside the use in preconditioning of linear system of equations will be presented to clarify the contribution of the paper. © 2013 F. Soleymani and Predrag S. Stanimirović.

Soleymani F.,Islamic Azad University at Zahedan
WSEAS Transactions on Information Science and Applications | Year: 2011

The calculation of derivatives of a function mostly takes up a great deal of time and even in some cases, such as the existing problems in engineering and optimization, is impossible to be evaluated directly. Accordingly, an accurate derivative-free class of three-step methods is suggested for solving f(x)=0. The proposed three-step technique comprises four evaluations of the function per iteration. The analytical proof of the main contribution is given. And finally, the accuracy of the developed techniques is tested numerically by solving numerical examples.

Razmjooy N.,Islamic Azad University at Majlesi | Mousavi B.S.,Islamic Azad University at Zahedan | Soleymani F.,Islamic Azad University at Zahedan
Computers and Mathematics with Applications | Year: 2012

Detection of external defects on potatoes is the most important technology in the realization of automatic potato sorting stations. This paper presents a hierarchical grading method applied to the potatoes. In this work a potato defect detection combining with size sorting system using the machine vision will be proposed. This work also will focus on the mathematics methods used in automation with a particular emphasis on the issues associated with designing, implementing and using classification algorithms to solve equations. In the first step, a simple size sorting based on mathematical binarization is described, and the second step is to segment the defects; to do this, color based classifiers are used. All the detection standards for this work are referenced from the United States Agriculture Department, and Canadian Food Industries. Results show that we have a high accuracy in both size sorting and classification. Experimental results show that support vector machines have very high accuracy and speed between classifiers for defect detection. © 2011 Elsevier Ltd. All rights reserved.

The views of Fazlollah Soleymani are presented on a letter written to the editor of Computing regarding a paper published by Khattri and other researchers on the derivative free algorithm for solving nonlinear equations. Researchers have discovered that there are gaps in the formulas 8 and 11 in the paper published by Khattri and Log. It has been found that the construction of their algorithm, which started from the relation 7 in the first formula is correct, but there are big typographical errors in the printed formulas. The authors have first considered a finite difference approximation for the first derivative in formula 4, as in the Steffensen method, approximating the free non-zero parameter in the error equation 6 to obtain the iterative method. The authors have claimed in formula 9 that the iterative method is of third order convergence, while a valid mathematical proof shows the method does not converge even linearly.

Karimi Vanani S.,Islamic Azad University at Zahedan | Soleymani F.,Islamic Azad University at Zahedan
Mathematical and Computer Modelling | Year: 2013

In this paper, we present a numerical solution of weakly singular Volterra integral equations including the Abel's equations by the Tau method with arbitrary polynomial bases. The Tau method produces approximate polynomial solutions of differential, integral and integro-differential equations. An extension of the Tau method has been done for the numerical solution of weakly singular Volterra integral equations, especially for Abel's equations. The integral part appearing in the equation is replaced by its operational Tau representation. An efficient error estimation of the Tau method is also introduced. Some numerical experiments are given to demonstrate the superior performance of the Tau method. The Chebyshev and Legendre bases are also introduced to improve the results. © 2012 Elsevier Ltd.

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