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Estimation of fracture toughness of cast steel container from Charpy impact test data
Tassadit Bellahcene,Meziane Aberkane 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.25 No.6
Fracture energy values KV have been measured on cast steel, used in the container manufacture, by instrumented Charpy impact testing. This material has a large ductility on the upper transition region at +20°C and a ductile tearing with an expended plasticity before a brittle fracture on the lower transition region at -20°C. To assess the fracture toughness of this material we use, the KIC-KV correlations to measure the critical stress intensity factor KIC on the lower transition region and the dynamic force - displacement curves to measure the critical fracture toughness JρC, the essential work of fracture Γe on the upper transition region. It is found, using the KIC-KV correlations, that the critical stress intensity factor KIC remains significant, on the lower transition region, which indicating that our testing material preserves his ductility at low temperature and it is apt to be used as a container’s material. It is, also, found that the Jρ−ρ energetic criterion, used on the upper transition region, gives a good evaluation of the fracture toughness closest to those found in the literature. Finally, we show, by using the Γe-KIC relation, on the lower transition region, that the essential work of fracture is not suitable for the toughness measurement because the strong scatter of the experimental data. To complete this study by a numerical approach we used the ANSYS code to determine the critical fracture toughness JANSYS on the upper transition region.
Hadji, Lazreg,Meziane, Mohamed Ait Amar,Safa, Abdelkader Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.66 No.6
This study deals with free vibrations analysis with stretching effect of nanocomposite beams reinforced by single-walled carbon nanotubes (SWCNTs) resting on an elastic foundation. Four different carbon nanotubes (CNTs) distributions including uniform and three types of functionally graded distributions of CNTs through the thickness are considered. The rule of mixture is used to describe the effective material properties of the nanocomposite beams. The significant feature of this model is that, in addition to including the shear deformation effect and stretching effect it deals with only 4 unknowns without including a shear correction factor. The governing equations are derived through using Hamilton's principle. Natural frequencies are obtained for nanocomposite beams. The mathematical models provided in this paper are numerically validated by comparison with some available results. New results of free vibration analyses of CNTRC beams based on the present theory with stretching effect is presented and discussed in details. The effects of different parameters of the beam on the vibration responses of CNTRC beam are discussed.
Hadj Henni Abdelaziz,Mohamed Ait Amar Meziane,Abdelmoumen Anis Bousahla,Abdelouahed Tounsi,S.R. Mahmoud,Afaf S. Alwabli 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.25 No.6
In this research, a simple hyperbolic shear deformation theory is developed and applied for the bending, vibration and buckling of powerly graded material (PGM) sandwich plate with various boundary conditions. The displacement field of the present model is selected based on a hyperbolic variation in the in-plane displacements across the plate‟s thickness. By splitting the deflection into the bending and shear parts, the number of unknowns and equations of motion of the present formulation is reduced and hence makes them simple to use. Equations of motion are obtained from Hamilton‟s principle. Numerical results for the natural frequencies, deflections and critical buckling loads of several types of powerly graded sandwich plates under various boundary conditions are presented. The accuracy of the present formulation is demonstrated by comparing the computed results with those available in the literature. As conclusion, this theory is as accurate as other theories available in the literature and so it becomes more attractive due to smaller number of unknowns.
Static and dynamic behavior of FGM plate using a new first shear deformation plate theory
Lazreg Hadji,M. Ait Amar Meziane,Z. Abdelhak,T. Hassaine Daouadji,E.A Adda Bedia 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.57 No.1
In this paper, a new first shear deformation plate theory based on neutral surface position is developed for the static and the free vibration analysis of functionally graded plates (FGPs). Moreover, the number of unknowns of this theory is the least one comparing with the traditional first-order and the other higher order shear deformation theories. The neutral surface position for a functionally graded plate which its material properties vary in the thickness direction is determined. The mechanical properties of the plate are assumed to vary continuously in the thickness direction by a simple power-law distribution in terms of the volume fractions of the constituents. Based on the present shear deformation plate theory and the neutral surface concept, the governing equations are derived from the principle of Hamilton. There is no stretchingbending coupling effect in the neutral surface based formulation. Numerical illustrations concern flexural and dynamic behavior of FG plates with Metal-Ceramic composition. Parametric studies are performed for varying ceramic volume fraction, length to thickness ratios. The accuracy of the present solutions is verified by comparing the obtained results with the existing solutions.
Larbi, Latifa Ould,Hadji, Lazreg,Meziane, Mohamed Ait Amar,Adda Bedia, E.A. Techno-Press 2018 Wind and Structures, An International Journal (WAS Vol.27 No.4
In this paper, a simple first-order shear deformation theory is presented for dynamic behavior of functionally graded beams. Unlike the existing first-order shear deformation theory, the present one contains only three unknowns and has strong similarities with the classical beam theory in many aspects such as equations of motion, boundary conditions, and stress resultant expressions. Equations of motion and boundary conditions are derived from Hamilton's principle. Analytical solutions of simply supported FG beam are obtained and the results are compared with Euler-Bernoulli beam and the other shear deformation beam theory results. Comparison studies show that this new first-order shear deformation theory can achieve the same accuracy of the existing first-order shear deformation theory.
Lazreg Hadji,Mohamed Ait Amar Meziane,Abdelkader Safa 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.66 No.6
This study deals with free vibrations analysis with stretching effect of nanocomposite beams reinforced by single-walled carbon nanotubes (SWCNTs) resting on an elastic foundation. Four different carbon nanotubes (CNTs) distributions including uniform and three types of functionally graded distributions of CNTs through the thickness are considered. The rule of mixture is used to describe the effective material properties of the nanocomposite beams. The significant feature of this model is that, in addition to including the shear deformation effect and stretching effect it deals with only 4 unknowns without including a shear correction factor. The governing equations are derived through using Hamilton’s principle. Natural frequencies are obtained for nanocomposite beams. The mathematical models provided in this paper are numerically validated by comparison with some available results. New results of free vibration analyses of CNTRC beams based on the present theory with stretching effect is presented and discussed in details. The effects of different parameters of the beam on the vibration responses of CNTRC beam are discussed.
Analysis of functionally graded beam using a new first-order shear deformation theory
Lazreg Hadji,T. Hassaine Daouadji,M. Ait Amar Meziane,Y. Tlidji,E.A. Adda Bedia 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.57 No.2
A new first-order shear deformation theory is developed for dynamic behavior of functionally graded beams. The equations governing the axial and transverse deformations of functionally graded plates are derived based on the present first-order shear deformation plate theory. The governing equations and boundary conditions of functionally graded beams have the simple forms as those of isotropic plates. The influences of the volume fraction index and thickness-to-length ratio on the fundamental frequencies are discussed.The accuracy of the present solutions is verified by comparing the obtained results with the existing solutions.
Abdessamad Imoulan,Muzammil Hussain,Paul M. Kirk,Abdellatif El Meziane,Yi-Jian Yao 한국응용곤충학회 2017 Journal of Asia-Pacific Entomology Vol.20 No.4
Beauveria species are the most common cosmopolitan insect-pathogenic fungi which parasitize over 700 insect species. Since the establishment of the Beauveria genus in 1912 by Vuillemin, its taxonomy status was relied particularly on classical morphological characters. Although easily distinguishable as a genus, species identification remains definitely complicated because of the lack of distinctive morphological features. Furthermore, the extensive overlap in conidia shape and dimensions among Beauveria species has limited their utility as key taxonomic structures. Species identification using only ITS region of rDNA as a DNA barcode reached its resolution limit within Beauveria. Recently, there is a tendency to move towards an integrative multi-locus delimitation system for closely related species. Up until now, a total of 17 Beauveria species have been established essentially reliant on the multi-genes barcode approach of four nuclear genes, i.e., RPB1, RPB2, TEF-1α and intergenic Bloc, adapting genealogical concordance phylogenetic species recognition criterion. This report reviews the taxonomic history of Beauveria species using both morphological and molecular data over the past century.
Lazreg Hadji,T. Hassaine Daouadji,M. Ait Amar Meziane,E. A. Adda Bedia 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.20 No.2
A theoretical method to predict the interfacial stresses in the adhesive layer of reinforced concrete beams strengthened with externally bonded carbon fiber-reinforced polymer (CFRP) plate is presented. The analysis provides efficient calculations for both shear and normal interfacial stresses in reinforced concrete beams strengthened with composite plates, and accounts for various effects of Poisson's ratio and Young's modulus of adhesive. Such interfacial stresses play a fundamental role in the mechanics of plated beams, because they can produce a sudden and premature failure. The analysis is based on equilibrium and deformations compatibility approach developed by Tounsi. In the present theoretical analysis, the adherend shear deformations are taken into account by assuming a parabolic shear stress through the thickness of both the reinforced concrete beam and bonded plate. The paper is concluded with a summary and recommendations for the design of the strengthened beam.
Latifa Ould Larbi,Lazreg Hadji,Mohamed Ait Amar Meziane,E.A. Adda Bedia 한국풍공학회 2018 Wind and Structures, An International Journal (WAS Vol.27 No.4
In this paper, a simple first-order shear deformation theory is presented for dynamic behavior of functionally graded beams. Unlike the existing first-order shear deformation theory, the present one contains only three unknowns and has strong similarities with the classical beam theory in many aspects such as equations of motion, boundary conditions, and stress resultant expressions. Equations of motion and boundary conditions are derived from Hamilton’s principle. Analytical solutions of simply supported FG beam are obtained and the results are compared with Euler-Bernoulli beam and the other shear deformation beam theory results. Comparison studies show that this new first-order shear deformation theory can achieve the same accuracy of the existing first-order shear deformation theory.