Bonded patch repairs for metallic structures – A new recommended practice

Echtermeyer, Andreas T.; McGeorge, Dag; Grave, Jon Harald Lambert; Weitzenböck, Jan

doi:10.1177/0731684413510754

Cited by 12 publications

(9 citation statements)

References 10 publications

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“…Most importantly, the welding cannot be applied in all areas of a ship since some locations are adjacent to fuel tanks and pose a potential fire risk, causing a cutting and welding procedure to be dismissed if fuel tanks are not emptied and properly cleaned before the repair. In such cases, a bonded patch repair based on fibre reinforced polymer (FRP) is a potential cost and time efficient repair solution [1]. This solution utilises fibres mixed with polymer resin.…”

Section: Figure 1: Frequent Problems Of Corrosion and Cracks On Various Positions On Different Vesselsmentioning

confidence: 99%

Study of Tube And Tank Specimens Repaired Using a Carbon Fibre Reinforced Epoxy

Frank¹,

Milat²,

Balunović³

et al. 2020

JMTS

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Merchant and passenger ships operate in harsh environments where they constantly suffer from corrosion and crack problems. The traditional cutting and welding of the steel parts most often requires redirection of a vessel to a shipyard what results in substantial vessel out-of-service time. In such situations, a ship operator seeks an efficient and fast repair solution to minimise ship delays. Following advancements in research and application of composite materials, an opportunity to implement composite patches made of carbon fibres and epoxy resin has emerged in the shipping industry as one of the cost and time efficient repair solutions. Although, the resin hardens and bonds the fibres strongly to the damaged surface, classification societies still consider this repair as a temporary solution and accept it conditionally, meaning with the frequent obligatory inspections. This is because there hasn’t been enough practical evidence yet to recognise the composite patching as the permanent repair solution. In order to further investigate the efficiency of the composite patching, this paper presents the finite element (FE) strength investigation of 17 patches applied to tube and tank specimens under water pressure. The future work will consider a validation of the obtained FE results by means of pressure testing during the course of the qualification process.

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Section: Figure 1: Frequent Problems Of Corrosion and Cracks On Various Positions On Different Vesselsmentioning

confidence: 99%

Study of Tube And Tank Specimens Repaired Using a Carbon Fibre Reinforced Epoxy

Frank¹,

Milat²,

Balunović³

et al. 2020

JMTS

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“…The strain energies given by the models both before and after defect growth were obtained and the SERRs were calculated as indicated by expression (4). For the smallest defect it resulted to be 69.7 J/m 2 and for the largest, 67.4 J/m 2 .…”

Section: Fem Model Of the Repaired Regionmentioning

confidence: 99%

“…In this study case the composite patch repair design followed the approach proposed at the DNV technical report "Project Recommended Practice of Composite Patch Repair for FPSO Structures" (DNV RP) [2][3][4]. The design has also utilized the Finite Element Method (FEM), starting from the global model of the ship as available in a database.…”

Section: Introductionmentioning

confidence: 99%

Experimental fatigue and aging evaluation of the composite patch repair of a metallic ship hull

2014

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This article describes the fatigue analysis of a composite repair that was applied to the metallic hull of a Floating, Storage and Offloading (FSO) platform. The main objective is to address the durability and thus the expected operational life of the repair, with emphasis on the adhesive bonded interface between metal and composite. The adoption of this repair technology is increasing in Brazil and abroad and little is known about its long term performance when applied to harsh, dynamic applications like naval structures in operation. During repair installation, more than a year ago, an array of Bragg grating extensometers was applied for reliable structural behavior monitoring. Dynamic strain samples were acquired daily and remotely sent to shore for processing. In parallel, lap shear fatigue tests were performed at the lab in order to establish a suitable defect growth fatigue curve, concerning repair disbondment. The experimental strain data, together with a specific fatigue curved experimentally defined provided the input of a Finite Element Model of the repaired structure and resulted in the expected fatigue life of the repair metal-composite interface. Environmental aging was beneficial as it resulted in a12% increase in the critical shear stress of the interface.

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“…The composite repair practices are well established. 1 -18 Despite the availability of so many books and technical papers for different patch designs of polymer composites, only a few papers are published in optimizing the patch designs for which the reason is provided that the “conservative approach” yields some extent of factor of safety around damage zones to avoid unnecessary complications. But today, everyone across the globe has the responsibility to make possible contribution in reducing the carbon footprint and pollution control, in order to sustain healthy environment.…”

Section: Introductionmentioning

confidence: 99%

Novel patch shape design to repair π/4 quasi-isotropic E-glass/epoxy laminate under uniaxial tensile loading condition

Gopalakrishnan¹,

Muthu²,

Subramanian

et al. 2018

Polymers and Polymer Composites

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The entitled technical subject in its comprehensive and broadly viewed study is presented by stating that the prevailing glass fiber–reinforced plastic composites play a vital role in replacing the metallic structures in automotive, aerospace, and marine applications and their more usage necessitates the better understanding of such structure’s damage and effective repair practices of the same. In the course of repairing the composite structures, optimum usage of patch material helps to maintain the original strength, eliminate “over design,” and reduce contribution to the substantial performance change of original structure. Optimum usage of repair material brings down the significant percentage of mass and repair cost. In order to apply the concept of optimum patch shapes over actual structures, it is important to design such effective shapes which are equivalent to the conventionally proven repair designs in strength perspective. This technical paper describes one of such ways to design the optimum patch shape using finite element analysis (FEA) tool and in comparison with one of the conventional repair practices, like circular patching, used circular, rectangular, square, elliptical and trapezoidal patch shapes, each of which has its own merits and demerits when compared to the other. But, none of them was arrived at in the perspective to use the minimum material to repair the damage. The object of this work is carried out in order to arrive at the optimum patch shape (minimum material in its in-plane direction) in repairing the damaged structure and it has been demonstrated using π/4 quasi-isotropic E-glass/epoxy specimen with hole using FEA. Moreover, the effectiveness of optimum patch shape design in “strength” and “load transfer efficiency” perspectives is experimentally proven and highlighted by the scope of repair material saving (36%) in repair practice by the usage of this optimized approach, as well.

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Bonded patch repairs for metallic structures – A new recommended practice

Cited by 12 publications

References 10 publications

Study of Tube And Tank Specimens Repaired Using a Carbon Fibre Reinforced Epoxy

Study of Tube And Tank Specimens Repaired Using a Carbon Fibre Reinforced Epoxy

Experimental fatigue and aging evaluation of the composite patch repair of a metallic ship hull

Novel patch shape design to repair π/4 quasi-isotropic E-glass/epoxy laminate under uniaxial tensile loading condition

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