Extending the Fatigue Life of Multi‐layer Metal Joints

Finney, J. M.; Evans, Richard M.

doi:10.1111/j.1460-2695.1995.tb00851.x

Cited by 14 publications

(3 citation statements)

References 6 publications

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“…The use of multilayer architectures in a thin overlay coating can improve the performance of components against the higher demands proposed in the design of many engineering applications, for example, the lower weight but higher engine output required for engines 1,2 . In the design of multilayer coatings, hard and soft materials are usually used together as they can provide great improvements in a series of properties, including fatigue performance, corrosion resistance, conformability, and embeddability 1,3–5 …”

Section: Introductionmentioning

confidence: 99%

Control of fatigue failure mechanisms in multilayer coatings by varying the architectural parameters of an intermetallic interlayer

Cook

Zhang³

et al. 2022

Fatigue Fract Eng Mat Struct

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A multilayer overlay coating system containing an intermediate intermetallic layer is an architecture expected to show good fatigue resistance. Experimental characterization and modeling simulations were carried out to classify the different crack initiation mechanisms occurring during fatigue of this coating system (2IML coating system) and to reveal how changes in the layer architecture lead to fatigue improvement. Surface crack initiation seems to play the dominated role in the fatigue failure of this coating system as over 55% of observed cracks were surface cracks. Fatigue improvement is achieved by increasing surface initiation resistance via decreasing the IML‐Top layer thickness. However, subsurface initiation mechanisms inhibit the improvement (dominated by surface initiation mechanism) achieved by locating the IML‐Top layer closer to the top surface. Optimizing the design of 2IML multilayer coatings based on the fatigue performance should eliminate the unreacted nickel layer in the intermediate IML‐Top layer, increase the subsurface interface strength, and decrease the density of voids occurring in the annealing process.

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Section: Introductionmentioning

confidence: 99%

Control of fatigue failure mechanisms in multilayer coatings by varying the architectural parameters of an intermetallic interlayer

Cook

Zhang³

et al. 2022

Fatigue Fract Eng Mat Struct

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“…These geometric notches are therefore susceptible to fatigue nucleation and subsequent crack propagation, requiring regular in-service inspection to be performed in order to maintain the structural integrity of an operational fleet. In an effort to increase the length of time before an initial inspection, and between recurring inspections, the Split Sleeve Cold Expansion TM (SSCx TM ) process was developed in the early 1970s by the Boeing Company, then later patented and marketed by Fatigue Technology Incorporation (FTI) [1,2]. The process introduces a deep residual compressive stress in the material around the processed fastener hole.…”

Section: Introductionmentioning

confidence: 99%

Mitigating Cutting-Induced Plasticity Errors in the Determination of Residual Stress at Cold Expanded Holes Using the Contour Method

et al. 2021

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Background The split sleeve cold expansion process is widely used to improve the fatigue life of fastener holes in the civil and military aircraft industry. The process introduces beneficial compressive residual stresses around the processed hole, but uncertainties remain about the character of the stress field immediately adjacent to the bore of the hole. Objective The primary objective of this study was to implement the contour method with minimising error associated with cutting-induced plasticity to provide detailed and reliable characterisation of the residual stress introduced by the split sleeve cold expansion process. Methods A systematic FE study of plasticity effects by simulating different contour cutting strategies (a single cut, two sequential cuts and a 6-cut sequence) for a cold expanded hole in an aluminium alloy coupon was conducted. The identified ‘optimum’ cutting strategy was then applied experimentally on coupons containing a hole that had been processed to 3.16% applied expansion. Results The FE study of different cutting simulations show that the locations of the stress error is consistent with the location where cutting-induced plasticity accumulated and that the magnitude and locations of stress re-distribution plasticity can be controlled by an optimised cutting strategy. In order to validate this hypothesis a high quality contour measurement was performed, showing that accurate near bore stress results can be achieved by the proposed 6-cut approach that controls cutting induced plasticity. Conclusions The present work has demonstrated that detailed FE simulation analysis can be a very effective tool in supporting the development of an optimum cutting sequence and in making correct choices of boundary conditions. Through optimizing these key aspects of the cutting sequence one is much more likely to have a successful, low error contour residual stress result.

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“…[10][11][12] Therefore, to compensate the drawback in these joints, various methods and techniques including cold expansion, interference fitting, and bolted clamping have been proposed to enhance the fatigue life of such structures. [10][11][12][13][14][15][16][17][18][19][20][21] Among them, interference fit is one of the most effective approaches in fatigue life enhancement and has been widely used in aircraft assembly. [8][9][10][11]13,[19][20] Due to the extensive applications of interference fit, numerous investigations reported in literatures have been conducted to prove that this method contributes to beneficial effects in various kinds of structures, such as aluminum alloy single-holed joints, single shear lap joints, and double shear lap joints; 2,[8][9][10][11]13,19 moreover, even better static, dynamic, and fatigue response in composite and titanium alloy joints can be seen through induced by this technology.…”

Section: Introductionmentioning

confidence: 99%

A new model for stress analysis in pin–Plate interference fit joints under tension loading

Zheng

Cao

Zuo

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part G:

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The decrease of stress amplitude is generally believed as the mechanism of fatigue life enhancement in interference fit joints under cyclic loading for each load cycle. In order to exactly estimate it, a new analytical model was presented. In this model, influences of mass, geometry, and plastic deformation are considered to modify and improve the spring model, and, moreover, the stress amplitude at the smallest crossing section is investigated. Taking these factors into account, stress amplitude decrease of various interference values can be calculated more accurately; therefore, the analytical solutions have good agreement with the finite element numerical and experimental results under different interference values and load levels. The analytical model indicates that the decrease ratio of stress amplitude is of a certain value for a specific interference value with the external load under the critical value. Furthermore, the decrease ratio of stress amplitude mainly depends on the stiffness of the pin and plate, which is mostly affected by the geometric shapes and plastic deformation ranges of the pin and plate. In addition, raising the interference value leads to larger stress amplitude reduction since the plastic deformation areas expand with the increment of interference values.

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Extending the Fatigue Life of Multi‐layer Metal Joints

Cited by 14 publications

References 6 publications

Control of fatigue failure mechanisms in multilayer coatings by varying the architectural parameters of an intermetallic interlayer

Control of fatigue failure mechanisms in multilayer coatings by varying the architectural parameters of an intermetallic interlayer

Mitigating Cutting-Induced Plasticity Errors in the Determination of Residual Stress at Cold Expanded Holes Using the Contour Method

A new model for stress analysis in pin–Plate interference fit joints under tension loading

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