Modified Natural Daftardar-Jafari Method for Solving Fuzzy Time-Fractional Wave Equation

Hamzeh Husin Zureigat 한국지능시스템학회 2023 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.23 No.4

Numerical solution of complex fuzzy heat equation in term of complex Dirichlet conditions

Hamzeh Zureigat,Abd Ulazeez Alkouri,Areen Al-khateeb,Eman Abuteen,Sana Abu-Ghurra 한국지능시스템학회 2023 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.23 No.1

Recently, complex fuzzy sets have become powerful tools for generalizing the range of fuzzy sets to wider ranges that lies on a unit disk in the complex plane. In this study, complex fuzzy numbers are discussed and applied for the first time to solve a complex fuzzy partial differential equation involving a complex fuzzy heat equation under Hukuhara differentiability. Subsequently, an explicit finite difference scheme, referred to as the forward time-center space, was implemented to solve the complex fuzzy heat equations. The imprecision of the issue is evident in the initial and boundary conditions, as well as in the amplitude and phase terms' coefficients, where the convex normalized triangular fuzzy numbers are extended to the unit disk in the complex plane. The proposed numerical methods utilized the properties and benefits of the complex fuzzy set theory. Furthermore, a new proof of consistency, stability, and convergence was established under this theory. A numerical example was provided to illustrate the reliability and feasibility of the proposed approach. The results obtained using the proposed approach are in adequate agreement with the exact solution and related theoretical aspects.

On Hoeffding and Bernstein type inequalities for sums of random variables in non-additive measure spaces and complete convergence

Hamzeh Agahi,Radko Mesiar,Mehran Motiee 한국통계학회 2016 Journal of the Korean Statistical Society Vol.45 No.3

Working with real phenomena, one often faces situations where additivity assumption is unavailable. Non-additive measures and Choquet integral are attracting much attention from scientists in many different areas such as financial economics, economic modelling, probability theory and statistics. Hoeffding’s and Bernstein’s inequalities are two powerful tools that can be applied in many studies of the asymptotic behaviour of inference problems in probability theory, model selection, stochastic processes and economic modelling. One thing that seems missing is the developments of Hoeffding’s and Bernstein’s inequalities for sums of random variables in non-additive cases. The purposes of this paper are to extend Hoeffding’s and Bernstein’s inequalities for sums of random variables from probability measure space to non-additive measure space, and then establish two complete convergence theorems for more general form.

Feasibility study of a novel copolyamide thin film composite membrane assisted by melamine in terms of acid and thermal stability

Hamzeh Hoseinpour,Mohsen Jahanshahi,Majid Peyravi,Ahmad Nozad 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.46 No.-

A new acid stable copolyamide [PEI-Mel]-PA membrane was developed via interfacial polymerizationassisted by melamine. The physico-chemical properties and separation ability were studied. It wascompared with an acid stable polysulfonamide membrane in terms of acid stability. Melamine improvedthe thermal and acid stability and made the surface of the membrane more positively charged. Thedecreases in MgSO4 rejections were 56% and 31% for [PEI-Mel]-PA membrane after H2SO4 and HNO3treatment, respectively. The stability of [PEI-Mel]-PA improved up to 16% and 48% in H2SO4 and HNO3,respectively in comparison with PEI-PA membrane. It recovered more than 97% of the acid.

Modeling and Multi-Constrained Optimization in Drilling Process of Carbon Fiber Reinforced Epoxy Composite

Hamzeh Shahrajabian,Masoud Farahnakian 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.

The goal of this study is to present a methodology for the determination of the optimal cutting parameters (spindle speed, feed rate and tool point angle) during the drilling process of carbon fiber reinforced polymer composites (CFRP) to maximize the material removal rate by considering surface roughness, delamination and thrust force as the constraints through coupling Response Surface Method (RSM) and Genetic Algorithm (GA). In this regard, the advantages of statistical experimental design technique, experimental measurements, Response Surface Method (RSM) and the genetic optimization method are exploited in an integrated manner. To this end, the experiments on CFRP were conducted to obtain surface roughness, delamination factor and thrust force values based on the full factorial design of experiments, and then analysis of variance (ANOVA) is performed. The predictive models for outputs were created using Response Surface Method (RSM) taking advantage of the experimental data. Material removal rate constituted the main function for the genetic algorithm, and thrust force, delamination, and surface roughness were applied as the constraints of the GA function. The function was optimized by the GA code, and finally, the optimum variables were obtained, and the results of the GA were tested experimentally. It can be clearly observed that good agreement exists between the predicted values and the experimental measurements.

Numerical investigation of continuous hollow steel beam strengthened using CFRP

Amir Hamzeh Keykha 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.66 No.4

This paper presents a numerical study on the behavior of continuous hollow steel beam strengthened using carbon fiber reinforced polymers (CFRP). Most previous studies on the CFRP strengthening of steel beams have been carried out on the steel beams with simple boundary conditions. No independent study, to the researcher’s knowledge, has studied on the CFRP strengthening of square hollow section (SHS) continuous steel beam. However, this study explored the effect of the use of adhesively bonded CFRP flexible sheets on the behavior of the continuous SHS steel beams. Finite Element Method (FEM) has been employed for modeling. Eleven specimens, ten of which were strengthened using CFRP sheets, were analyzed under different coverage length, the number of layers, and the location of CFRP composite. ANSYS software was used to analyze the SHS steel beams. The results showed that the coverage length, the number of layers, and the location of CFRP composite are effective in increasing the ultimate load capacity of the continuous SHS steel beams. Application of CFRP composite also caused the ductility increase some strengthened specimens.

Direct displacement based design of hybrid passive resistive truss girder frames

Amir Hamzeh Shaghaghian,Morteza Raissi Dehkordi,Mahdi Eghbali 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.28 No.6

An innovative Hybrid Passive Resistive configuration for Truss Girder Frames (HPR-TGFs) is introduced in the present study. The proposed system is principally consisting of Fluid Viscous Dampers (FVDs) and Buckling Restrained Braces (BRBs) as its seismic resistive components. Concurrent utilization of these devices will develop an efficient energy dissipating mechanism which is able to mitigate lateral displacements as well as the base shear, simultaneously. However, under certain circumstances which the presence of FVDs might not be essential, the proposed configuration has the potential to incorporate double BRBs in order to achieve the redundancy of alternative load bearing paths. This study is extending the modern Direct Displacement Based Design (DDBD) procedure as the design methodology for HPR-TGF systems. Based on a series of nonlinear time history analysis, it is demonstrated that the design outcomes are almost identical to the pre-assumed design criteria. This implies that the ultimate characteristics of HPR-TGFs such as lateral stiffness and inter-story drifts are well-proportioned through the proposed design procedure.

Numerical investigation of SHS steel beam-columns strengthened using CFRP composite

Amir Hamzeh Keykha 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.25 No.5

Carbon Fiber Reinforced Polymer (CFRP) is one of the materials used to strengthen steel structures. Most studies on strengthening steel structures have been done on steel beams and steel columns. No independent study, to the researcher’s knowledge, has studied the effect of CFRP strengthening on steel beam-columns, and it seems that there is a lack of understanding on behavior of CFRP strengthening on steel beam-columns. However, this study explored the use of adhesively bonded CFRP flexible sheets on retrofitting square hollow section (SHS) steel beam-columns, using numerical investigations. Finite Element Method (FEM) was employed for modeling. To determine the ultimate load of SHS steel beam-columns, ten specimens, eight of which were strengthened with the different coverage length and with one and two CFRP layers, with two types of section (Type A and B) were analyzed. ANSYS was used to analyze the SHS steel beam-columns. The results showed that the CFRP composite had no similar effect on the slender and stocky SHS steel beam-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 beam-columns.

Reliability study of CFRP externally bonded concrete beams designed by FIB bulletin 14 considering corrosion effects

Dehghani, Hamzeh Techno-Press 2022 Advances in concrete construction Vol.13 No.2

FIB is introduced as the sole guideline for the design purpose that results in a practical relationship for the torsional capacity of concrete beams strengthened with carbon fiber-reinforced polymer (CFRP). This study applies first-order reliability method to assess the reliability evaluation of the torsional capacity of CFRP-strengthened beams on the basis of FIB guidelines. In terms of steel reinforcement losses, this study applies a corrosion model to investigate the ceaseless deterioration of the existing structure. Hence, the average of reliability indices varies between 2.68 and 2.80, indicating the reliability viewpoint of the design methodologies. The average values are somehow low compared to the target values of reliability (3.0 or 3.5) applied in the calibration stage of the FIB guideline. In this way, the partial safety factors may change in the forthcoming guideline revisions. For this aim, the reliability of strengthening ratio was applied to assess the variation in the average value of the reliability index with different partial safety factors. The performance of parametric study for the factor proved that minimum values of 1.60 and 2.32 are required for target values of reliability (3.0 and 3.5), respectively.

CFRP strengthening of steel columns subjected to eccentric compression loading

Amir Hamzeh Keykha 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.23 No.1

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.