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A new formulation of the J integral of bonded composite repair in aircraft structures
Nassim Serier,Belaïd Mechab,Rachid Mhamdia,Boualem Serier 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.58 No.5
A three-dimensional finite element method is used for analysis of repairing cracks in plates with bonded composite patch in elastic and elastic plastic analysis. This study was performed in order to establish an analytical model of the J-integral for repair crack. This formulation of the J-integral to establish models of fatigue crack growth in repairing aircraft structures. The model was developed by interpolation of numerical results. The obtained results were compared with those calculated with the finite element method. It was found that our model gives a good agreement of the J-integral. The arrow shape reduces the J integral at the crack tip, which improves the repair efficiency.
Influence of porosity on the behavior of cement orthopaedic of total hip prosthesis
Ali, Benouis,Boualem, Serier,Smail, Benbarek Techno-Press 2015 Biomaterials and biomedical engineering Vol.2 No.4
This paper presents three-dimensional finite element method analyses of the distribution of equivalents stress of Von Mises. Induced around a cavity located in the bone cement polymethylmethacrylate (PMMA). The presences and effect of its position in the cement was demonstrated, thus on the stress level and distribution. The porosity interaction depending on their positions, and their orientations on the interdistances their mechanical behaviour of bone cement effects were analysed. The obtained results show that micro-porosity located in the proximal and distal zone of the prosthesis is subject to higher stress field. We show that the breaking strain of the cement is largely taken when the cement, containing the porosities very close adjacent to each other.
Effect of cavity-defects interaction on the mechanical behavior of the bone cement
Zouambi, Leila,Serier, Boualem,Benamara, Nabil Techno-Press 2014 Advances in materials research Vol.3 No.1
The presence of cavities in the bone cement has a great importance for the transport of antibiotics, but its existence in this material can lead to its weakening by notch effect. The aim of this study allows providing a physical interpretation to the cavities interconnection by cracks observed experimentally. The most important stress of Von Mises is localized at the cement/bone interface near the free edge which is the seat of stress concentration. The presence and interaction of cavities in this site concentrate, by notch effect, stresses which tend to the tensile fracture stress of Bone cement.
Influence of porosity on the behavior of cement orthopaedic of total hip prosthesis
Ali, Benouis,Boualem, Serier,Smail, Benbarek Techno-Press 2015 Biomaterials and Biomechanics in Bioengineering Vol.2 No.4
This paper presents three-dimensional finite element method analyses of the distribution of equivalents stress of Von Mises. Induced around a cavity located in the bone cement polymethylmethacrylate (PMMA). The presences and effect of its position in the cement was demonstrated, thus on the stress level and distribution. The porosity interaction depending on their positions, and their orientations on the interdistances their mechanical behaviour of bone cement effects were analysed. The obtained results show that micro-porosity located in the proximal and distal zone of the prosthesis is subject to higher stress field. We show that the breaking strain of the cement is largely taken when the cement, containing the porosities very close adjacent to each other.
New optimization method of patch shape to improve the effectiveness of cracked plates repair
Mohamed S. Bouchiba,Boualem Serier 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.58 No.2
An optimization method of patch shape was developed in this study, in order to improve repair of cracked plates. It aimed to minimize three objectives: stress intensity factor, patch volume and shear stresses in the adhesive film. The choice of these objectives ensures improving crack repair, gaining mass and enhancing the adhesion durability between the fractured plate and the composite patch. This was a multi-objective optimization combined with Finite elements calculations to find out the best distribution of patch height with respect to its width. The implementation of the method identified families of optimal shapes with specific geometric features around the crack tip and at the horizontal end of the patch. Considerable mass gain was achieved while improving the repair efficiency and keeping the adhesive shear stress at low levels.
Experimental and numerical prediction of the weakened zone of a ceramic bonded to a metal
Zaoui, Bouchra,Baghdadi, Mohammed,Mechab, Belaid,Serier, Boualem,Belhouari, Mohammed Techno-Press 2019 Advances in materials research Vol.8 No.4
In this study, a three-dimensional Finite Element Model has been developed to estimate the size of the weakened zone in a bi-material a ceramic bonded to metal. The calculations results were compared to those obtained using Scanning Electron Microscope (SEM). In the case of elastic-plastic behaviour of the structure, it has been shown that the simulation results are coherent with the experimental findings. This indicates that Finite Element modeling allows an accurate prediction and estimation of the weakening effect of residual stresses on the bonding interface of Alumina. The obtained results show us that the three-dimensional numerical simulation used by the Finite Element Method, allows a good prediction of the weakened zone extent of a ceramic, which is bonded with a metal.
Numerical analysis of crack propagation in cement PMMA: application of SED approach
Benouis Ali,Boulenouar Abdelkader,Benseddiq Noureddine,Serier Boualem 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.55 No.1
Finite element analysis (FEA) combined with the concepts of linear elastic fracture mechanics (LEFM) provides a practical and convenient means to study the fracture and crack growth of materials. In this paper, a numerical modeling of crack propagation in the cement mantle of the reconstructed acetabulum is presented. This work is based on the implementation of the displacement extrapolation method (DEM) and the strain energy density (SED) theory in a finite element code. At each crack increment length, the kinking angle is evaluated as a function of stress intensity factors (SIFs). In this paper, we analyzed the mechanical behavior of cracks initiated in the cement mantle by evaluating the SIFs. The effect of the defect on the crack propagation path was highlighted.
Numerical simulation of the femur fracture under static loading
Zagane Mohammed El Sallah,Benbarek Smail,Sahli Abderahmane,B. Bachir Bouiadjra,Serier Boualem 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.60 No.3
Bone is a living material with a complex hierarchical structure that gives it remarkable mechanical properties. Bone constantly undergoes mechanical. Its quality and resistance to fracture is constantly changing over time through the process of bone remodeling. Numerical modeling allows the study of the bone mechanical behavior and the prediction of different trauma caused by accidents without expose humans to real tests. The aim of this work is the modeling of the femur fracture under static solicitation to create a numerical model to simulate this element fracture. This modeling will contribute to improve the design of the indoor environment to be better safe for the passengers’ transportation means. Results show that vertical loading leads to the femur neck fracture and horizontal loading leads to the fracture of the femur diaphysis. The isotropic consideration of the bone leads to bone fracture by crack propagation but the orthotropic consideration leads to the fragmentation of the bone.
Ibrahim, Nour Chafak,Bouanani, Morad Fari,Bouiadjra, Bel Abbes Bachir,Serier, Boualem Techno-Press 2016 Advances in materials research Vol.5 No.1
In bonded composite repair of aircraft structures, the damage of the adhesive can thus reduce significantly the efficiency and the durability of the bonded composite repair. The adhesive damage models using critical zone have proven their effectiveness due to simplicity and ap-plicability of the damage criteria in these models. The scope of this study is to analyze the effects of the patch thickness and the adhesive thickness on the damage damage in bonded composite repair of aircraft structures by using modified damage zone theory. The obtained results show that, when the thickness of adhesive increases the damage zone increases and the adhesive loses its rigidity, inversely when the patch is reduced the adhesive damage be-comes more significant.
Abderahmane, Sahli,Mokhtar, Bouziane M.,Smail, Benbarek,Wayne, Steven F.,Zhang, Liang,Belabbes, Bachir Bouiadjra,Boualem, Serier Techno-Press 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.63 No.3
Through the use of finite element analysis and acoustic emission techniques we have evaluated the interfacial failure of a carbon fiber reinforced polymer (CFRP) repair patch on a notched aluminum substrate. The repair of cracks is a very common and widely used practice in the aeronautics field to extend the life of cracked sheet metal panels. The process consists of adhesively bonding a patch that encompasses the notched site to provide additional strength, thereby increasing life and avoiding costly replacements. The mechanical strength of the bonded joint relies mainly on the bonding of the adhesive to the plate and patch stiffness. Stress concentrations at crack tips promote disbonding of the composite patch from the substrate, consequently reducing the bonded area, which makes this a critical aspect of repair effectiveness. In this paper we examine patch disbonding by calculating the influence of notch tip stress on disbond area and verify computational results with acoustic emission (AE) measurements obtained from specimens subjected to uniaxial tension. The FE results showed that disbonding first occurs between the patch and the substrate close to free edge of the patch followed by failure around the tip of the notch, both highest stress regions. Experimental results revealed that cement adhesion at the aluminum interface was the limiting factor in patch performance. The patch did not appear to strengthen the aluminum substrate when measured by stress-strain due to early stage disbonding. Analysis of the AE signals provided insight to the disbond locations and progression at the metal-adhesive interface. Crack growth from the notch in the aluminum was not observed until the stress reached a critical level, an instant before final fracture, which was unaffected by the patch due to early stage disbonding. The FE model was further utilized to study the effects of patch fiber orientation and increased adhesive strength. The model revealed that the effectiveness of patch repairs is strongly dependent upon the combined interactions of adhesive bond strength and fiber orientation.