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Bel Abbes Bachir Bouiadjra - One of the best experts on this subject based on the ideXlab platform.

  • Bonded Composite Repairs Analysis in Pipes Under Internal Pressure Using Finite Element Technics
    Proceedings of the Third International Symposium on Materials and Sustainable Development, 2018
    Co-Authors: A. Achour, Bel Abbes Bachir Bouiadjra, Djamel Ouinas
    Abstract:

    The use of Composite systems as a repair methodology in the pipeline industry has grown in recent years. However, there are still no widely accepted standards governing the design and installation of such systems but the potential cost savings can be significant. Whilst Composite repairs are gaining acceptance and approvals they do not as yet have full regulatory approval and this should be considered during the repair assessment process. In this study, the analysis of the behaviour of circumferential through cracks in repaired pipe with Bonded Composite Patch subjected to internal pressure is performed using three dimensional finite element methods. The stress intensity factor is used as a fracture criteria which describes the elastic behavior of the structure. The obtained results show that the presence of the Bonded Composite Patch reduces significantly the stress intensity factor, what can improve the lifespan of the pipe.

  • Fatigue crack propagation in aluminum plates with Composite Patch including plasticity effect
    Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering, 2017
    Co-Authors: A Albedah, Bel Abbes Bachir Bouiadjra, Sohail M A Khan, F Benyahia
    Abstract:

    In this paper, we analyzed experimentally and numerically the behavior of fatigue crack in aluminum plates repaired with Bonded Composite Patch. We studied the behavior of repaired crack in AA 2024...

  • Mass Gain Estimation Between Double and Single-Bonded Composite Repairs for Inclined Cracks in Aircraft Structures
    2016
    Co-Authors: A Albedah, F Benyahia, M. Es-saheb, M. Berrahou, Bel Abbes Bachir Bouiadjra
    Abstract:

    ABSTRACT: Repair of cracked components by an adhesively Bonded Composite Patch has gained acceptance in aerospace structures. The advantages of the double symmetric repair compared to the single one are well known. These advantages permit a significant reduction of the stress intensity near the repaired defect. In this study, a new approach was used to determine the advantage of the double symmetric Patch: it is the determination of the mass gain obtained by the use of the double Patch if the two techniques (single and double Patches) give the same stress intensity at the crack tip. The mass gain was estimated numerically using the three-dimensional finite element method for repaired inclined cracks. The obtained results show that the mass gain eventually obtained by the use of the double Patch can be very significant

  • experimental analysis of the fatigue life of repaired cracked plate in aluminum alloy 7075 with Bonded Composite Patch
    Engineering Fracture Mechanics, 2015
    Co-Authors: A Albedah, F Benyahia, Sohail M A Khan, Bel Abbes Bachir Bouiadjra
    Abstract:

    Abstract In this study, we analyzed the fatigue behavior of a V-notch crack in an aluminum alloy 7075-T6 plate repaired with Bonded Composite Patch under constant and stepped variable amplitude loading. The effect of adhesive disbond on the repair performance was analyzed. The obtained results confirm the need of repairing cracks at their early creation for a maximum repair performance and showed that the increases in the disbond width and the stress ratio have a large negative effect on the repair efficiency. The latter is low for increasing loading blocks but significantly high for decreasing blocks.

  • experimental and numerical analysis of Bonded Composite Patch repair in aluminum alloy 7075 t6
    Materials & Design, 2015
    Co-Authors: F Benyahia, Bel Abbes Bachir Bouiadjra, A Albedah, L Aminallah, Tahar Achour
    Abstract:

    Abstract In this study, the performances of aged Bonded Composite repair of aircraft structures have been evaluated by conducting experimental and numerical investigations. The accelerating aging of the Patch was realized by immersion in water for 120 days. The performance of aged and non-aged Bonded Composite Patches in the repair of cracked structures was evaluated. The experimental results showed that the fatigue life of the aircraft structures can be significantly improved with the Patch repair. The Patch aging reduces the repair performances because of the reduction of the Composite rigidity by humidity absorption. Numerical results show that the stress intensity factor at the crack tip is significantly reduced by the presence of the Patch. The humidity absorption increases the stress intensity factor at the crack tip and decreases the adhesive stresses. Nevertheless, the repair durability cannot be improved by the humidity absorption because it leads to a reduction of the mechanical resistance of the adhesive.

M Belhouari - One of the best experts on this subject based on the ideXlab platform.

Benali Boutabout - One of the best experts on this subject based on the ideXlab platform.

  • Fracture energy for repaired cracks with Bonded Composite Patch having two adhesive bands in aircraft structures
    Computational Materials Science, 2007
    Co-Authors: Bel Abbes Bachir Bouiadjra, Hamida Fekirini, M Belhouari, Benali Boutabout, Boualem Serier
    Abstract:

    Adhesive in Bonded Composite repair plays two opposite roles. The first consists in ensuring the transfer of load between the Composite Patch and the cracked aluminium component. The second role is to ensure the connection between these two structures in order to avoid the adhesive failure. In this study, a method of repair is proposed; it consists in dividing the adhesive layer into two bands with different properties. The first band is used on the crack region to ensure the stress transfer and the second band is used beyond the crack region to avoid the adhesive failure. The energy release rate at the crack tip is computed for this repair configuration using the finite element method. The obtained results show that the energy release rate at the crack tips is highly reduce by the difference of properties between the two adhesive bands, what can involve the improvement of fatigue life of cracked structure.

  • computation of the stress intensity factor for Patched crack with Bonded Composite repair in pure mode ii
    Composite Structures, 2003
    Co-Authors: Abdelkader Megueni, Bel Abbes Bachir Bouiadjra, Benali Boutabout
    Abstract:

    The finite element method is carried out to analyse the performance of the Bonded Composite Patch for repairing cracks in pure mode II by computing the stress intensity factor at the crack tip. The effects of the Patch size and the adhesive thickness on the stress intensity factor variation are highlighted. The comparison between double and single Patch repairs is also given in this study. The obtained results shows that, like in pure mode I, the mode II stress intensity factor exhibits an asymptotic behaviour as the crack length increases. There is a significant difference in the reduction of the SIF between the single and double sided Patch.

Abdelkader Megueni - One of the best experts on this subject based on the ideXlab platform.

Shankar Mall - One of the best experts on this subject based on the ideXlab platform.

  • investigation into cracked aluminum plate repaired with Bonded Composite Patch
    Composite Structures, 2007
    Co-Authors: V Sabelkin, Shankar Mall, M A Hansen, R M Vandawaker, M Derriso
    Abstract:

    Abstract Several parameters/factors related to mechanical and fatigue behaviors of a cracked 7075-T6 aluminum panel repaired with one-sided adhesively Bonded Composite Patch were studied by a combined experimental–analytical approach. These were strain distribution, out-of-plane deformation and residual strength along with crack growth behavior. The effects of cool-down temperature during Patch bonding, disbond and bending moment were also investigated. Residual thermal stresses, developed during Patch bonding, requires the knowledge of temperature at which adhesive becomes effective in creating a bond between the specimen and Patch. This can be determined through the out-of-plane deformation of the repaired panel. A bending moment is developed upon application of axial load due to initial out-of-plane deformation of the repaired panel with one-sided Bonded Patch. This can be also determined from the out-of-plane deformation. Further, the bending moment and temperature change during Patch curing have a relatively more effect on the out-of-plane deformation than on the in-plane strain of the repaired panel. The disbond does not affect the out-of-plane deformation and in-plane strain except in their vicinity. Crack length has a small effect upon the in-plane strain and out-of-plane deformation. The stress intensity factor varies along the thickness of the repaired panel; however, crack growth rate was primarily dominated by stress intensity factor near the Bonded Patch side of the thin repaired panel in the present study. The Bonded Patch repair of a cracked panel provides a considerable increase in the residual strength as well as fatigue life.

  • modeling of cracked thick metallic structure with Bonded Composite Patch repair using three layer technique
    Composite Structures, 1999
    Co-Authors: J J Schubbe, Shankar Mall
    Abstract:

    A finite element analysis involving three-layers of two-dimensional Mindlin plate elements, to model cracked plate, adhesive, and Composite Patch, was developed to characterize fatigue crack growth behavior of a thick metallic panel repaired with an adhesively Bonded Composite Patch. Also, fatigue experiments were conducted with 6.35 mm thick specimens with a pre-crack repaired asymmetrically with adhesively Bonded unidirectional boron/epoxy Patch. Fatigue crack growth rates on the unPatched and Patched faces (PF) were measured along with debond of the Composite Patch. Stress intensity factors obtained from the analysis were combined with the fatigue crack growth relationship for the unrepaired cracked material to obtain the analytical fatigue crack growth rates. The experimental and analytical fatigue crack growth rates on the unPatched face (UPF) were in a good agreement with each other when the proper consideration of the effective crack length and debond were incorporated in the analysis. Thus, the three-layer technique was found to be capable of characterizing the fatigue crack growth behavior of the repaired thick panels as in the case of repaired thin panels shown in the previous studies.

  • Methodology to analyse aerospace structures repaired with a Bonded Composite Patch
    The Journal of Strain Analysis for Engineering Design, 1999
    Co-Authors: Sam Naboulsi, Shankar Mall
    Abstract:

    AbstractAdhesively Bonded Composite repair of metallic structures is one of the candidate technologies that has enormous potential in the ageing aircraft. A computational tool to analyse the repaired aerospace structure using an adhesively Bonded Composite Patch is presented. This involves the three-layer technique based on the two-dimensional finite element method for adhesively Bonded Composite Patch repair of cracked structures. This technique is capable of characterizing the crack growth and debond growth behaviour, as well as predicting the fatigue life extension of the repaired structure with a perfectly or imperfectly Bonded Patch. Also, the thermal effects which may develop during bonding or during service and the non-linear material behaviour of the adhesive are incorporated in this technique. The results from the three-layer technique show good agreement with experimental results as well as a previous investigator's published numerical results. Besides the accuracy of the technique, the advantag...

  • ANALYSIS OF CRACKED METALLIC STRUCTURE WITH IMPERFECTLY Bonded Composite Patch
    38th Structures Structural Dynamics and Materials Conference, 1997
    Co-Authors: Sam Naboulsi, Shankar Mall
    Abstract:

    Adhesively Bonded Patches are an efficient and economical way to improve the damage tolerance of cracked metallic structures. Debonds in adhesively Bonded repairs reduce the damage tolerance of the repaired structure. Hence, it is necessary to investigate the damage tolerance of imperfectly Bonded Patch. An investigation of debond is performed in this study to understand its characteristics and quantify the magnitude of damage caused by debond through out the life expectancy of the repair. The three layer technique is used to compute the stress intensity factors for the cohesive crack and the strain energy release rate for the adhesive crack. The accuracy of the three layer model to compute the stress intensity factors for the cohesive crack are validated with their experimental counterparts. The experimental stress intensity factors are computed using the Paris law where the material constants used are those calculated for unPatched specimen. The comparison shows a very good agreements between the experimental and analytical stress intensity factors for both completely Bonded Patch and imperfectly Bonded Patch under thermo-mechanical loading. Furthermore, the analytical stress intensity factors computed at the mid-plane and free edge of the cracked plate bound their experimental counterparts. Both the experimental and analytical results show that the crack growth inside the Patch is linearly dependent on the crack length.

  • Characterization of fatigue crack growth in aluminium panels with a Bonded Composite Patch
    Composite Structures, 1997
    Co-Authors: Sam Naboulsi, Shankar Mall
    Abstract:

    This study introduces an analytical procedure to characterize the fatigue crack growth behavior in an aluminium panel repaired with a Bonded Composite Patch. This procedure involves the computation of the stress intensity factor from a two-dimensional finite element method consisting of three layers to model cracked plate, adhesive and Composite Patch. In this three layer finite element analysis, as recently introduced by the authors, two-dimensional Mindlin plate elements with transverse shear deformation capability are used. The computed stress intensity factor is then compared with the experimental counterpart. The latter was obtained from the measured fatigue crack growth rate of an aluminium panel with a Bonded Patch by using the power law relationship (Paris Law) of an unPatched aluminum panel. Both a completely Bonded Patch (with no debond) and a partially Bonded Patch (with debond) are investigated in this study. This procedure, thus, provides an effective and reliable technique to predict the fatigue life of a repaired structure with a Bonded Patch, or alternatively, it can be used to design the Bonded Composite Patch configuration to enhance the fatigue life of cracked structure.