International Journal of Adhesion & Adhesives 100 (2020) 102594 Available online 17 March 2020 0143-7496/© 2020 Elsevier Ltd. All rights reserved. Development of pipe repairs using bonded metal plate – Part I: Shape factor, stiffness and surface treatment Ricardo Hudson da Silva a , Eduardo Martins Sampaio a , Ney Robson Rohem b , Ranulfo Martins Carneiro Neto c, * a Laboratory of Adhesion and Adherence, University of State of Rio de Janeiro, Polytechnic Institute, Nova Friburgo, RJ, Brazil b Instituto Federal Fluminense, Maca� e, Rio de Janeiro, Brazil c Center of Technology and Application of Composite Materials, Federal University of Rio de Janeiro, Aloísio da Silva Gomes Ave, 50, 27930-560, Maca� e, RJ, Brazil A R T I C L E INFO Keywords: Shape factor Surface treatment Bonded joints Pipe repair ABSTRACT This work aims to study the resistance of repairs with bonded plates in pipes with holes subjected to hydrostatic pressure. It is a promising alternative for application in low-risk repairs (up to 1 MPa). Due to the differences between the circumferential and transverse stresses in the pipes, the inﬂuence of the bonded plate area in the joint strength was evaluated, checking whether the shape factor occurs. The effect of plate thickness in the repair strength, besides the addition of silane on the plate surfaces, were also studied. Finally, considering a control plate based in the performed experiments, the surface treatment inﬂuence on the tubes was evaluated in the face of rupture pressure of the system. High hydrostatic resistance values were found, demonstrating the efﬁciency of the procedures used in the repair. The studies show little inﬂuence on the repair strength due to dimensions variation in different directions, and high inﬂuence on the surface treatment, stiffness and bonded area increase. The work aims to initiate the development of a new procedure for contingency repair with low risk. 1. Introduction Adhesive joints have been widely used in the areas of oil industry, aerospace, automotive and others in general. Advantages of bonded joints include: i) a more uniform stress distribution compared to con- ventional joints (screws, rivets and welding), ii) do not require heat input in their application, which implies a better weather resistance, iii) simple application and lighter structure [1,2]. These properties have motivated the making of many researches works on this subject. Due to the great use of pipelines to transport liquids and gases, several studies directed to the maintenance of the failures have been carried out. Pipe repairs cover a variety of damage situations, corrosion being the main cause [3], but they also include dents, gouges, fretting, cracks, leaks and manufacturing defects, according to ASME PCC 2 [4]. The repairs may be temporary or permanent. The temporary repairs include bolted clamps or ﬁxtures and can involve metal deposits, as in a sleeve-repair welding. Although this method usually results in good strength obtained in the ﬁnal repair, it is possible that the pipe-wall melts through or that, martensite is formed, in addition to residual stresses in the pipe wall [5]. All these factors have welding as main cause. The temporary repairs are done for a ﬁxed time and should be replaced later by a permanent repair, which include the replace of the entire pipe (requiring production stops, in addition to being expensive and slow), nonmetallic liners and wraps (composite materials). Numerous papers have studied the repair of steel pipes with lami- nated composites, (e.g. Saeed et al. [6], Rohem et al. [7] and Budhe et al. [8]), however, few studies have been done related to repairs with bonded plates. In a recent work, Çitil et al. [9] investigated the pipe repair with bonded plates. Artiﬁcial cracks were created on the pipes and repairs were made using adhesive and galvanized steel patches with different overlap lengths and thickness. After subjecting the pipes to internal pressure, the study concluded that the larger the thickness of the patch the greater the internal pressure capacity. Regarding increasing overlap length, the internal pressure capacity did not change signiﬁ- cantly. In addition, the experimental and numerical results data are very similar. The repair of small holes using composite patches was studied by Ayaz et al. [10]. The repaired pipes were subjected to internal pressure until damage occurred. The results showed that the greater the * Corresponding author. E-mail addresses: rhudsonsilva@gmail.com (R.H. da Silva), edu.msampaio@gmail.com (E.M. Sampaio), neyrohem@gmail.com (N.R. Rohem), ranulfocarneiro@ macae.ufrj.br, ranulfocarneiro@yahoo.com.br (R.M.C. Neto). Contents lists available at ScienceDirect International Journal of Adhesion and Adhesives journal homepage: http://www.elsevier.com/locate/ijadhadh https://doi.org/10.1016/j.ijadhadh.2020.102594 Received 8 February 2020; Accepted 10 March 2020