Hybrid approaches for aircraft primary structure repairs

Wang, J.; Baker, A.A.; Chang, Po-Yao

doi:10.1016/j.compstruct.2018.09.038

Cited by 15 publications

(6 citation statements)

References 31 publications

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“…Cold expansion during riveting [28][29][30][31] greatly improves fatigue life of aluminium alloy joints by introducing compressive residual stress at the hole. Subsequently, the service life of holed parts increases significantly since it is difficult for cracks to propagate through a compressive field [6,32]. To capture this effect, riveted and hybrid configurations were drilled and reamed using a 4.20 mm reamer, producing a 0.02 mm clearance to allow for cold working under the forces of expanding rivets.…”

Section: Methodsmentioning

confidence: 99%

“…Adhesive bonding has inherent mechanical advantages over mechanical fastening methods, such as pins, screws, bolts, and rivets, owing to: weight savings, sealing, elimination of galvanic corrosion, and relatively uniform stress distributions that avoid high stress concentrations otherwise present at fastener holes [5]. Repairs using adhesive bonding save millions of dollars and significantly enhance aircraft availability [6,7]. However, the challenge for adhesive bonding arises from certification requirements on some critical primary aircraft structures (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Numerical and experimental studies on the joint performance of fastened, bonded, and hybrid thin metal joints used in aircraft structures

Ekladious

2023

Materials Research Proceedings

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Abstract. Static strength of mechanically fastened, bonded, and hybrid double lap joints are investigated in this study. Aerospace grade 7075-T6 aluminium alloy was chosen for the adherend as it is a widely used primary aircraft structure material. Mechanical fasteners were arranged in square array patterns to resemble typical rivet arrangements in airframes. The aim was to compare the joint performance of three distinct joining/repairing mechanisms: purely riveted, purely bonded, and a hybrid of both rivets and adhesive bonding. Finite element analysis (FEA) verification of the riveted configuration static strength indicated accurate prediction of both joint strength and failure mode. Detailed results will be reported in the paper. This paper presents the first stage of a systematic research program assessing the damage tolerance behaviour of crack growth, and design assessment of adhesive bonded/hybrid metallic joints under static and fatigue loadings, to achieve the optimum joint design for applications.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical and experimental studies on the joint performance of fastened, bonded, and hybrid thin metal joints used in aircraft structures

Ekladious

2023

Materials Research Proceedings

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“…The analysis of different locations and several diameters of drilling was carried out to determine the optimal diameter and its location. Goto et al [19] have shown that drilling a hole near the crack tip has an influence on the direction of crack propagation and can increase the fatigue life of the cracked structure.Thomas et al [20]have studied the inflence of the drilling distance of a hole from the crack tip. A combination of drilled hole method and composite patch was carried out in this work, the hybrid repair (stop hole/bonded composite) was applied to the notched plates where the stop hole center is located on the notch-tip.…”

Section: Effect Of Drilling Hole Diameter(ρ)mentioning

confidence: 99%

Failure behavior of a notched plate repaired by a hybrid repair technique (Stop hole bonded composite

Belhamiani

Djebbar

Oudad

et al. 2023

Preprint

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Generally, bonded repairs are only approved if the primary aircraft structure is cracked and the residual strength significantly exceeds the design limit charge before the bonded repair can be applied.. In order to improve the maintenance effect of the stop hole approach for cracks, a solution of using both techniques (stop hole / bonded composite repairs) are proposed and investigated by finite element analysis. This work presents a study on the effectiveness of the hybrid repair technique in notched panels using both stop drilling hole and bonded composite repair techniques. Several parameters are taken into account: the diameter of the size of hole drilling, the width and the thickness of the composite patch and other parameters are modeled with a elastoplastic behavior of the plate using Abaqus software. A limit-load analysis determines a lower bound to the limit charge of a component and provides an alternative way to estimate plastic collapse for the limit loads. In addition, the limit load analysis had helped to provide an evaluation of the behaviors of structures or components for other failures. The plastic limit load (PLL) was evaluated by a convergent load increment in a wellconfigured finite element analysis with a load of a sufficiently small increment for an elastic-perfectly plastic behavior of the structure. The allowable limit stress on the aircraft is calculated by applying design factors to the plastic limit load (PLL) so that the onset of plastic collapse does not occur. The results proved that the hybrid repair provided the largest percentage in terms of maintenance and the smallest values for the notch stress intensity factor (NSIF) and von Mises stress for most of the hybrid configuration compared to the single repair technique.

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“…Repairs are carried out in order to restore the original strength of the structure and stop the process of damage development [12,13]. In aviation, two basic methods of repairing aircraft skin are used: the method with the use of metal patches and mechanical joints [14] and the use of composite patches and adhesive joints [15,16] or alternatively a hybrid solution [17,18,19]. Due to the technological susceptibility of fiber-reinforced composite materials, these types of materials are used to repair not only composite but also metal structures.…”

Section: Introdutionmentioning

confidence: 99%

Analysis of the Airframe Repair Node

Rośkowicz¹,

Barca²

2022

TiAM

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Polymer composite materials can be used both for the production of semi-monocoque structures and for the repair of aircraft airframes. Of all the elements of the semi-monocoque structure, the airframe skin is most often damaged during operation. The fragments of the skin between the frame elements of the semi-monocoque structure are considered as a thin-walled plate. The paper presents an analysis of the repair node of a metal plate subjected to uniform shear. The model of the repaired plate made in the Ansys Workbench environment was used for the analysis. The boundary conditions were defined by means of an articulated frame using the possibilities of the computing environment in the scope of, defining elements among others. The model was initially verified experimentally, assuming that it can be used to carry out a comparative analysis of two methods of repairing a damaged plate, using CFRP (Carbon Fiber Reinforced Polymer) and GFRP (Glass Fiber Reinforced Polymer) materials. Analyzing the obtained results, it was found that the repair does not restore the original strength of the damaged structure, however, it reduces the stress of the plate material around the opening by 10%.

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Hybrid approaches for aircraft primary structure repairs

Cited by 15 publications

References 31 publications

Numerical and experimental studies on the joint performance of fastened, bonded, and hybrid thin metal joints used in aircraft structures

Numerical and experimental studies on the joint performance of fastened, bonded, and hybrid thin metal joints used in aircraft structures

Failure behavior of a notched plate repaired by a hybrid repair technique (Stop hole bonded composite

Analysis of the Airframe Repair Node

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