Browsing by Author "Khatir, S."

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    Application of proper orthogonal decomposition and radial basis functions for crack size estimation using particle swarm optimization
    (IOP Publishing, 2017) Benaissa, B.; Köppen, M.; Abdel Wahab, M.; Khatir, S.
    Complex engineering problems require simulations, which are computationally expensive in cases of inverse identification tasks since they commonly requires hundreds of thousands of simulations. This paper propose a method based on model reduction for crack size estimation, combining the proper orthogonal decomposition method with radial basis functions. The reduced model is validated by comparing the obtained boundary displacements with the corresponding results from a finite element model. This inverse procedure is formulated as the minimization of the difference between the measured and computed values of displacement at selected boundary nodes, called sensor points, using particle swarm optimization algorithm. Convex and a non-convex specimens have been considered for investigations of crack presence, and identification of its size, different crack sizes have been tested to demonstrate the efficiency of the proposed approach
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    Crack growth estimation using model reduction and genetic algorithm
    (· · · · ·, 2014) Benaissa, B.; Belaidi, Idir; Khatir, S.; Hamrani, A.; Lessoued, M.; Sahali, M. A.
    In this study we use the material elastic properties as a base, a tow dimensional cracked plate under traction is modelled by finite element method (FEM) than a reduced model is built using the proper orthogonal decomposition method (POD), the crack length is estimated as an inverse identification problem, basing on the deformation obtained from the boundary nodes of the structure considered as sensor points. A genetic algorithm (GA) is used for the minimization of the error function which is expressed as the difference between displacement field of the boundaries caused by the crack size proposed randomly by GA and the field measured at the actual identity. The approach presented accurate results and could guess the real crack size in a precession less that 10-6 of the cost function, proving its effectiveness even with a very low number of 4 sensors, and shows that the boundary displacement measurements are practical. The use of the reduced model provides tangible benefits mainly the very low computational cost
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    Notch depth identification in CFRP composite beams based on modal analysis using artificial neural network
    (Springer, 2023) Zara, A.; Belaidi, I.; Oulad Brahim, A.; Khatir, S.; Capozucca, R.; Abdel Wahab, M.
    Recently, the development of optimization techniques based on artificial neural network (ANN) has shown considerable progress in the field of damage identification in composite structures, due to their simplicity, greater precision, and lower computational time compared to non-destructive testing methods (NDT). In our work, a finite element model is developed using ABAQUS software to validate the vibratory behaviors of experimental tests. Then, based on digital data extracted from a calibrated model of the damaged CFRP cantilever specimens, we used a novel artificial neural network approach to detect and identify notch depth in carbon fiber reinforced polymer (CFRP) beam based on modal analysis. The results show that ANN based on natural frequencies can be used to identify notch depth with good accuracy in composite structures
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    Numerical simulation of cracked orthotropic materials using extended isogeometric analysis
    (IOP Publishing, 2017) Habib, Sadam Houcine; Belaidi, Idir; Khatir, S.; Abdel Wahab, M.
    In the present study, extended isogeometric analysis (XIGA) is used to analyse cracks in orthotropic media. NURBS and T-splines geometric technologies are used to define the geometry and the solution. Knot insertion and order elevation are used in NURBS models, while a new local refinement algorithm is applied to T-spline models. In XIGA, the basic idea of the extended finite element method (X-FEM) is used along with isogeometric analysis for modelling discontinuities by including enrichment functions. Special orthotropic crack tip enrichments are used to reproduce the singular fields near a crack tip, and fracture properties of the models are defined by the mixed mode stress intensity factors (SIFs), which are obtained by means of the interaction integral (M-integral). Results of the proposed method are compared with other available results