Issue 50

M. Baghdadi et alii, Frattura ed Integrità Strutturale, 50 (2019) 68-85; DOI: 10.3221/IGF-ESIS.50.08 68 Modeling of a cracked and repaired Al 2024T3 aircraft plate: effect of the composite patch shape on the repair performance Baghdadi Mohammed , Serier Boualem, Salem Mokadem, Zaoui Bouchra, Kaddouri Khacem University of Djillali Liabes, Laboratory of Mechanics Physics of Materials (LMPM Laboratory), Sidi Bel Abbes, Algeria. mohbagh0@gmail.com , boualems@yahoo.fr , Moka_salem@yahoo.fr , zaouibouchra55@yahoo.com , kaddourikacem@yahoo.fr A BSTRACT . In this work the finite element method was used to analyse the composite patch shape effect of the repair performance. Unlike all the works done conducted so far in this domain, this work proposed here, takes into account the reducing both, the stress intensity factor in repairing crack heads and the maximum shear stresses in the adhesive layer. This is the originality of this work. In function of the surface and the volume of the rectangular patch, three cases were taken into consideration: with conservation of the patches surface and its volume, with a reduction of the patches surface and its volumes, and in the end, with a reduction of the patches surface and conservation of its volume. The obtained results show that in the first case, the patch shape have no effect on the SIF, the sharp edges (obtuse, right and acute) of oblique shapes generate high shear stresses, in the second case, the reduced surfaces lead to significant mass gain with the same SIF values. and to an increase in the maximum shear stresses, in the latter case the patches shapes lead to a reduction of the SIF and the shear stresses. K EYWORDS . Patch; Composite; SIF; Stress; Shape; Adhesive; Crack. Citation: Baghdadi, M., Serier, B., Salem, M., Zaoui, B., Kaddouri, K . , Modeling of a cracked and repaired Al 2024T3 aircraft plate: Effect of the composite patch shape on the repair performance, Frattura ed Integrità Strutturale, 50 (2019) 68-85. Received: 18.02.2019 Accepted: 07.07.2019 Published: 01.10.2019 Copyright: © 2019 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION he birth of cracks in a structure metal in any field, such as aeronautical and marine structures, is a major concern of maintenance operators. To extend the life of these structures, Becker [1] has developed a repair technique which consists of bonded a composite patch with polymer matrices, usually epoxy, on the cracked area. This technique has shown its effectiveness in reducing of the stress intensity factor (SIF) at the crack tip, and by improving the behaviour of the damage structures durability [2,3]. In addition to their high stiffness, these composites materials offer good corrosion resistance and low density. The quality of the repair depends on several parameters, geometrical and mechanical on the composite patch and the adhesive layer. Thus, the composite patches shapes seem to be a determining element of the repair effectiveness. This is the objective of several research projects, Bouchiba and al [4] have developed a static approach to optimise the composite patch shape, they conclude that the butterfly shape reduces the failure energy in T