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Effect of stacking sequence of the bonded composite patch on repair performance
Hadja Imane Beloufa,Djamel Ouinas,Mostapha Tarfaoui,Noureddine Benderdouche 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.57 No.2
In this study, the three-dimensional finite element method is used to determine the stress intensity factor in Mode I and Mixed mode of a centered crack in an aluminum specimen repaired by a composite patch using contour integral. Various mesh densities were used to achieve convergence of the results. The effect of adhesive joint thickness, patch thickness, patch-specimen interface and layer sequence on the SIF was highlighted. The results obtained show that the patch-specimen contact surface is the best indicator of the deceleration of crack propagation, and hence of SIF reduction. Thus, the reduction in rigidity of the patch especially at adhesive layer-patch interface, allows the lowering of shear and normal stresses in the adhesive joint. The choice of the orientation of the adhesive layer-patch contact is important in the evolution of the shear and peel stresses. The patch will be more beneficial and effective while using the cross-layer on the contact surface.
Fatima Z. Zaoui,Djamel Ouinas,Abdelouahed Tounsi,Belkacem Achour,Jaime A. Viña Olay,Tayyab A. Butt 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.47 No.5
In this research, a new two-dimensional (2D) and quasi three-dimensional (quasi-3D) higher order shear deformation theory is devised to address the bending problem of functionally graded plates resting on an elastic foundation. The displacement field of the suggested theories takes into account a parabolic transverse shear deformation shape function and satisfies shear stress free boundary conditions on the plate surfaces. It is expressed as a combination of trigonometric and exponential shear shape functions. The Pasternak mathematical model is considered for the elastic foundation. The material properties vary constantly across the FG plate thickness using different distributions as power-law, exponential and Mori– Tanaka model. By using the virtual works principle and Navier's technique, the governing equations of FG plates exposed to sinusoidal and evenly distributed loads are developed. The effects of material composition, geometrical parameters, stretching effect and foundation parameters on deflection, axial displacements and stresses are discussed in detail in this work. The obtained results are compared with those reported in earlier works to show the precision and simplicity of the current formulations. A very good agreement is found between the predicted results and the available solutions of other higher order theories. Future mechanical analyses of three-dimensionally FG plate structures can use the study's findings as benchmarks.
A refined HSDT for bending and dynamic analysis of FGM plates
Fatima Zohra Zaoui,Abdelouahed Tounsi,Djamel Ouinas,Jaime A. Viña Olay 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.74 No.1
In this work, a novel higher-order shear deformation theory (HSDT) for static and free vibration analysis of functionally graded (FG) plates is proposed. Unlike the conventional HSDTs, the proposed theory has a novel displacement field which includes undetermined integral terms and contains fewer unknowns. Equations of motion are obtained by using Hamilton’s principle. Analytical solutions for the bending and dynamic investigation are determined for simply supported FG plates. The computed results are compared with 3D and quasi-3D solutions and those provided by other plate theories. Numerical results demonstrate that the proposed HSDT can achieve the same accuracy of the conventional HSDTs which have more number of variables.
Evaluation of energy release rate of composites laminated with finite element method
Habib Achache,Benali Boutabout,Abdelouahab Benzerdjeb,Djamel Ouinas 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.55 No.1
Control of the mechanical behavior of composite materials and structures under monotonic and dynamic loads for cracks and damage is a vast and complex area of research. The modeling of the different physical phenomena and behavior characteristics of a composite material during deformation play an important role in the structural design. Our study aims to analyze numerically the energy release rate parameter G of a composite laminated plate (glass or boron / epoxy) cross-ply [+α, −α] in the presence of a crack between two circular notches under the effect of several parameters such as fiber orientation α, the crack orientation β, the orientation γ of the two considered circular notches and the effect of mechanical properties. Our results show clearly that both notches orientation has more effect on G than the cracks and fibers orientations.
Zaoui, Fatima Zohra,Tounsi, Abdelouahed,Ouinas, Djamel Techno-Press 2017 Smart Structures and Systems, An International Jou Vol.20 No.4
In this article, a free vibration analysis of functionally graded (FG) plates resting on elastic foundations is presented using a quasi-3D hybrid-type higher order shear deformation theory. Undetermined integral terms are employed in the proposed displacement field and modeled based on a hybrid-type (sinusoidal and parabolic) quasi-3D HSDT with five unknowns in which the stretching effect is taken into account. Thus, it can be said that the significant feature of this theory is that it deals with only 5 unknowns as the first order shear deformation theory (FSDT). The elastic foundation parameters are introduced in the present formulation by following the Pasternak (two-parameter) mathematical model. Equations of motion are obtained via the Hamilton's principles and solved using Navier's method. Accuracy of the proposed theory is confirmed by comparing the results of numerical examples with the ones available in literature.
Delamination of a composite laminated under monotonic loading
Habib Achache,Abdelouahab Benzerdjeb,Abdelkader Mehidi,Benali Boutabout,Djamel Ouinas 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.63 No.5
Our work aims to analyze using the finite element method the evolution of the stress intensity factor (SIF) parameter K of three laminated folded plates stacks [+a,-a], made of the same epoxy matrix and different reinforcement fibers (boron, graphite and glass). Our results show that the angle of orientation of the boron/epoxy composite has no great influence on the variation of the parameter KI. Compared to composite graphite/epoxy and glass/epoxy, the laminated composite boron/epoxy reduces more the SIF KI in the middle of the plate for angles 0 <= a <= 30.
Delamination of a composite laminated under monotonic loading
Achache, Habib,Benzerdjeb, Abdelouahab,Mehidi, Abdelkader,Boutabout, Benali,Ouinas, Djamel Techno-Press 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.63 No.5
Our work aims to analyze using the finite element method the evolution of the stress intensity factor (SIF) parameter K of three laminated folded plates stacks [$+{\alpha}$, $-{\alpha}$], made of the same epoxy matrix and different reinforcement fibers (boron, graphite and glass). Our results show that the angle of orientation of the boron/epoxy composite has no great influence on the variation of the parameter KI. Compared to composite graphite/epoxy and glass/epoxy, the laminated composite boron/epoxy reduces more the SIF KI in the middle of the plate for angles $0^{\circ}{\leq}{\alpha}{\leq}30^{\circ}$.