Design and analysis of adhesively bonded thick composite patch repair of corrosion grind-out and cracks on 2024 T3 clad aluminum aging aircraft structures

Okafor, Anthony Chukwujekwu; Bhogapurapu, Hari

doi:10.1016/j.compstruct.2006.06.020

Cited by 19 publications

(9 citation statements)

References 5 publications

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“…The patch design adopted in this work is based on literature study [8,11,12] and our previous works that showing evidence on the effectiveness size of the patch needed for bridging the crack opening [13]. It was found the key factors influence the patched structure including patch configuration, patch geometry, patch thickness, and adhesive thickness.…”

Section: Patch Application On Steel Samplesmentioning

confidence: 99%

“…On the mechanical behavior of patched structures, CFRP serves as the function of moderating crack propagation because bridging CFRP materials over the cracks facilitate the crack closure by decreasing the crack openings and reducing the stress at the crack tips [6]. In addition to crack mitigation, the sample's load carrying ability increases dramatically after application of the patching layer [7]. The patch shape and dimensions, the adhesive material and its thickness must all be chosen before performing a composite patch repair [8] .…”

Section: Introductionmentioning

confidence: 99%

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Application of an engineered composite patch toward crack damage mitigation on stainless steel plates

Amiri

Chao

2023

Nondestructive Characterization and Monitoring of Advanced Materials, Aerospace, Civil Infrastructure, and Transportation XVII

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High level nuclear spent fuel canisters have been designed and used for nuclear waste storage since the 1950’s. Stress corrosion cracking (SCC) has shown to occur under certain corrosive chemical conditions when the residual stress was not relived in a welded plate. Typical SCC would eventually cause catastrophic failure of structures. In the case of spent nuclear canisters, the radioactive materials may leak through the cracks if they penetrate the tank wall. Early detection of SCC is crucial, followed with appropriate mitigation methods. Various mitigation methods have been funded and explored for the nuclear facilities. Among them, engineered composite patch repairing technique that was originally developed and adopted for aerospace aluminum structures has been proposed as one of the solutions. The technique begins with describing the sample preparation procedures. Based on nondestructive evaluation (NDE) techniques, the bonding between the composite patch and the repaired steel plate was then thoroughly examined using ultrasonic Lamb wave modes. The results were analyzed, and our findings demonstrated that the bonded composite patch was an effective way for crack mitigation. It was observed that they reduced the wave interactions and modified the Lamb wave modes propagation. The results were also helpful in determining the differences between the fully bonded sample and the flawed bonded sample.

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Section: Patch Application On Steel Samplesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Application of an engineered composite patch toward crack damage mitigation on stainless steel plates

Amiri

Chao

2023

Nondestructive Characterization and Monitoring of Advanced Materials, Aerospace, Civil Infrastructure, and Transportation XVII

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“…The detailed procedure and considerations for designing a composite patch are presented in a previous work of the authors. 12,13 The edges of the patch were tapered to reduce peel stresses. All the patches are made of five plies giving a stiffness ratio of 1.14.…”

Section: Design and Fabrication Of Patch Patch Designmentioning

confidence: 99%

Acoustic emission detection and prediction of fatigue crack propagation in composite patch repairs using neural network

Okafor

Singh

et al. 2016

Journal of Thermoplastic Composite Materials

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This article presents the results of acoustic emission (AE) monitoring of crack propagation in 2024-T3 clad aluminum panels repaired with adhesively bonded octagonal and elliptical boron/epoxy composite patches using FM-73 adhesive under tension-tension fatigue loading. Two crack propagation gages and four broadband AE sensors were used to monitor crack initiation and propagation, respectively. The acquired AE signals were processed in time and frequency domain to identify sensor features correlated with fatigue cycle and crack propagation, which were used to train neural networks for predicting crack length. The results show that AE events are correlated with crack propagation, and crack propagation signals can be differentiated from signals due to matrix cracking, fiber breakage, and shear of the composite patch. Three backpropagation cascade feed-forward networks were trained to predict crack length using number of fatigue cycles, number of AE events, and number of fatigue cycles and number of AE events together as inputs, respectively. It was found that network with fatigue cycles as input gave good results, while the network with just AE events as input gave greater error. However, the network using both fatigue cycles and number of AE events as inputs to predict crack length gave much better results.

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“…Successful results have been obtained in the composite patch repair of the body and inner surface areas of different structural elements and especially aircraft by using adhesive [8][9][10][11][12][13]; in addition to increasing fatigue and corrosion resistance of structure, it has been found that patches easily adapted to complex shapes [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

The Impact Degrees of Basic Parameters on Repair Performance in Composite Patch Applications

Yücel

Zor

Doğan

et al. 2019

Celal Bayar Üniversitesi Fen Bilimleri Dergisi

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In this study, for composite patch repairs, the impact degrees of patch configuration and patch sizes on repair performance were determined and compared with each other. First, stress intensity factor (SIF) values were calculated by using the Finite Element Method for tensile loading in an aluminum plate with center cracks, in unpatched situation. In this model, the repair was made by forming single and double sided patches and adhesive volumes too. The SIF values are recalculated for different patch thicknesses, widths, and crack lengths. The criterion that determines the impact degrees of the examined parameters was accepted to be the reduction rate in the SIF values. The results show that even the most disadvantageous patch application contributes significantly to the repair performance and that the application itself is the most effective factor. The second most effective parameter is patch configuration; the patch sizes have much less impact degree.

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Design and analysis of adhesively bonded thick composite patch repair of corrosion grind-out and cracks on 2024 T3 clad aluminum aging aircraft structures

Cited by 19 publications

References 5 publications

Application of an engineered composite patch toward crack damage mitigation on stainless steel plates

Application of an engineered composite patch toward crack damage mitigation on stainless steel plates

Acoustic emission detection and prediction of fatigue crack propagation in composite patch repairs using neural network

The Impact Degrees of Basic Parameters on Repair Performance in Composite Patch Applications

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