Abstract
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.
Highlights
The birth of cracks in a structure metal in any field, such as aeronautical and marine structures, is a major concern of maintenance operators
I t has been reported previously that the composite patch shapes have a significant effect on the performance and reliability of the repair in terms of reduction of the stress intensity factor in crack heads and the shear stresses in the adhesive layer
Whatever the applied stress intensities, the repair becomes more and more effective and efficient with the use of the wider patch. This behaviour was observed by Dajmel Ouinas [16] and al, Mahadesh Kumar and al. [13] and confirmed by Ramji and al. [10] as well as by Kashfuddoja and al. [11] that have demonstrated the effectiveness of designing an elongated patch in the direction perpendicular to the tensile loading. This efficiency is closely related to optimizing the height of this patch, noted HP, it is clearly shown that the composite patches with higher heights lead to a clear decrease in the stress intensity factor (SIF) in mode I (Fig 5.b)
Summary
The 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. 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
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call