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Numerical study of bonded composite patch repair in damaged laminate composites
Azzeddine, Nacira,Benkheira, Ameur,Fekih, Sidi Mohamed,Belhouari, Mohamed Techno-Press 2020 Advances in aircraft and spacecraft science Vol.7 No.2
The present study deals with the repair of composite structures by bonding composite patches. The composite structure is a carbon/epoxy laminate with stacking sequence [45/-45/0/90]S. The damaged zone is simulated by a central crack and repaired by bonding symmetrical composite patches. The repair is carried out using composite patches laminated from the same elemental folds as those of the cracked specimen. Three-dimensional finite element method is used to determine the energy release rate along the front of repaired crack. The effects of the repair technique used single or double patch, the stacking sequence of the cracked composite patch and the adhesive properties were highlighted on the variations of the fracture energy in mode I and mixed mode I + II loading.
Geometrical parameters optimizations of scarf and double scarf bounded joint
Fekih, Sidi Mohamed,Madani, Kuider,Benbarek, Smail,Belhouari, Mohamed Techno-Press 2018 Advances in aircraft and spacecraft science Vol.5 No.3
The aim of this work is to optimize the geometrical parameters as the adhesive thickness and the beveled angle to reduce the edge effect of the scarf and V bounded joint. A finite element analysis is done to define the generated stresses in the bounded joint. The geometrical optimum is obtained using the Experimental Design Method. Results show that the double scarf (V) joint is better than the simple scarf bounded joint.
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.
N. Kaddouri,K. Madani,S.CH. Djebbar,M. Belhouari,R.D.S.G. Campliho 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.84 No.6
Adhesive bonding has seen rapid development in recent years, with emphasis to composite patch repairing processes of geometric defects in aeronautical structures. However, its use is still limited given its low resistance to climatic conditions and requirement of specialized labor to avoid fabrication induced defects, such as air bubbles, cracks, and cavities. This work aims to numerically analyze, by the finite element method, the failure behavior of a damaged plate, in the form of a bonding defect, and repaired by an adhesively bonded composite patch. The position and size of the defect were studied. The results of the numerical analysis clearly showed that the position of the defect in the adhesive layer has a large effect on the value of J-Integral. The reduction in the value of J-Integral is also related to the composite stacking sequence which, according to the mechanical properties of the ply, provides better load transfer from the plate to the repair piece through the adhesive. In addition, the increase in the applied load significantly affects the value of the J-Integral at the crack tip in the presence of a bonding defect, even for small dimensions, by reducing the load transfer.