Crack propagation behaviour in fretting fatigue

Sato, Kenkichi; Fujii, Hiromasa; Kodama, Shotaro

doi:10.1016/0043-1648(86)90228-0

Cited by 45 publications

(7 citation statements)

References 8 publications

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“…l / b = 0.1, 0.5 and 0.9 are considered for the end profiles of the punch to cover the contact traction of a Hertzian‐like ( l / b = 0.1) to a square punch‐like ( l / b = 0.9) profiles. For the crack obliquity, θ = 0°, 30° are used here to cover the oblique angle of a fretting fatigue crack, which has been observed as 10–27° and 15–30° in the previous experiments. Lager obliquities have also been reported, such as up to 55° or even to around 60°.…”

Section: Numerical Results and Discussionsupporting

confidence: 69%

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Analysis of edge crack behaviour influenced by non‐symmetrical contact tractions and bulk tension

Kim

2014

Fatigue Fract Eng Mat Struct

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A B S T R A C T This paper analyses a crack growth behaviour, which is initiated from the contact edge between a square punch with rounded edges and a half plane. Investigated are the influences of the contact profile, magnitude of the bulk tension and, crack obliquity, in particular, misalignment between the punch and half plane on the variation of the stress intensity factors K I and K II during the crack growth. The misalignment is simulated by a tilting of the punch. A partial slip regime is considered for the contact shear force to accommodate a general fretting fatigue condition. It was found that a crack closure occurs if only the contact forces are applied. The crack grows longer before it is closed if the punch is tilted (clockwise, in this paper) such that it initiates at the opposite site with respect to the direction of tilting. The closure phenomenon disappears when the bulk tension is added and exceeds a certain magnitude, which significantly depends on not only the contact profile but also the degree and direction of tilting. Provided are the lowest values of the bulk tensile stress due to a fatigue load necessary to extend the crack without a closure for each condition of the contact profile and misalignment. This may be used as a design guideline to restrain the contact-induced failure.Keywords contact-induced failure; contact profile; crack closure; misalignment. N O M E N C L A T U R Ea = crack length A = combined elastic properties of contacting bodies b, b ref = a half contact length and a reference half contact length (at l/b = 0.1), respectively b i (i = x, y, x′, y′) = Burgers vector B(u), B i ( j) (i = x, y, x′, y′; j = s, s′) = dislocation density functions f = coefficient of friction G = shear modulus = crack driving force h(x), g(x) = normal and tangential displacements on the contact surface due to contact tractions, respectively k(v,u), k J i y′; s′ ð Þ (i = x′ or y′; J = N or T ) = kernels l, R, W = flat region, corner radius and width of a punch with rounded corners (see Figure 1) in order n = number of integration points along the crack line N = number of subdivisions of the contact region p(x), q(x) = contact normal and shear tractions, respectively p m , p ref m = averaged contact normal traction and its reference (at l/b = 0.1) P, Q = contact normal and shear forces, respectively s = location of a pseudo edge dislocation on the crack measured from the contact surface

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Section: Numerical Results and Discussionsupporting

confidence: 69%

“…The characteristic behaviour of such a crack is usually observed as follows. First, the crack initiated from the contact edge grows into the body obliquely owing to the comparatively stronger influence of the contact forces than the bulk fatigue load. Both modes I and II driving forces extend the crack.…”

Section: Introductionmentioning

confidence: 99%

Analysis of edge crack behaviour influenced by non‐symmetrical contact tractions and bulk tension

Kim

2014

Fatigue Fract Eng Mat Struct

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“…Under the Level 8 wind, the crack initially propagated perpendicular to the axis and then along the direction 45° to the axis for a long time. Finally, it slightly changed at the moment of instantaneous break [27][28][29]. In addition, the micro finite element model of wires was established.…”

Section: Results Of Simulation Experimentsmentioning

confidence: 99%

Research on Failure Mechanisms of Broken Strands of Jumper Wires for EHV Transmission Lines in Strong-Wind Areas

Han

Yongjie

et al. 2019

Metals

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The jumper wires of an extra-high voltage (EHV) transmission line in strong-wind areas in Northwest China frequently break down. We installed some acquisition devices to collect the data of the jumper wires and wind speed in the fault area of one 750-kV transmission line. We also developed a swing simulation machine based on the collected data. The machine could simulate the swing condition of the jumper wires under various wind speeds. We analyzed the broken aluminum wires obtained from the simulation experiment of jumper wires. Yield lines appeared on the surface of the broken aluminum wires in the simulation experiment. Proliferation of dislocation and grain deformation occurred in the broken aluminum wires using transmission electron microscopy observation. The results show that the aluminum wires in the experiment under a Level-6 wind and above were in a full yield state and demonstrated strain-fatigue failure condition. The fracture of the broken aluminum wires showed distinct strain-fatigue fracture characteristics using the scanning electron microscope fracture morphology analysis. From the combination of the abovementioned research, we conclude that the failure mechanism of the broken strands of the jumper wires of the EHV transmission line in the strong-wind area is mainly a strain-fatigue failure mechanism.

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“…Fretting initiated fatigue has long been recognized as a major cause of blade dovetail and disk slot failures in aircraft turbine engines. 1,2,3 Extensive research in the areas of contact mechanics, 4,5 crack initiation mechanisms 6,7 and the failure process 8,9 have led to a good understanding of the factors involved in the initiation and propagation of fretting damage. Because fretting fatigue damage occurs under complex mechanical loading and load-interactions between the two contacting surfaces, several factors affect the fatigue performance.…”

Section: Introductionmentioning

confidence: 99%

Mitigation of Fretting Fatigue Damage in Blade and Disk Pressure Faces With Low Plasticity Burnishing

Prevéy

Jayaraman

Ravindranath

et al. 2010

Journal of Engineering for Gas Turbines and Power

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Low plasticity burnishing (LPB) is now established as a surface enhancement technology capable of introducing through-thickness compressive residual stresses in the edges of gas turbine engine blades and vanes to mitigate foreign object damage (FOD). The “fatigue design diagram” (FDD) method has been described and demonstrated to determine the depth and magnitude of compression required to achieve the optimum high cycle fatigue strength, and to mitigate a given depth of damage characterized by the fatigue stress concentration factor, kf. LPB surface treatment technology and the FDD method have been combined to successfully mitigate a wide variety of surface damage ranging from FOD to corrosion pits in titanium and steel gas turbine engine compressor and fan components. LPB mitigation of fretting-induced damage in Ti–6Al–4V in laboratory samples has now been extended to fan and compressor components. LPB tooling technology recently developed to allow the processing of the pressure faces of fan and compressor blade dovetails and mating disk slots is described. Fretting-induced microcracks that form at the pressure face edge of bedding on both the blade dovetail and the dovetail disk slots in Ti-6-4 compressor components can now be arrested by the introduction of deep stable compression in conventional computer numerical control (CNC) machine tools during manufacture or overhaul. The compressive residual stress field design method employing the FDD approach developed at Lambda Technologies is described in application to mitigate fretting damage. The depth and magnitude of compression and the fatigue and damage tolerance achieved are presented. It was found that microcracks as deep as 0.030in.(0.75mm) large enough to be readily detected by current nondestructive inspection (NDI) technology can be fully arrested by LPB. The depth of compression achieved could allow NDI screening followed by LPB processing of critical components to reliably restore fatigue performance and extend component life.

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Crack propagation behaviour in fretting fatigue

Cited by 45 publications

References 8 publications

Analysis of edge crack behaviour influenced by non‐symmetrical contact tractions and bulk tension

Analysis of edge crack behaviour influenced by non‐symmetrical contact tractions and bulk tension

Research on Failure Mechanisms of Broken Strands of Jumper Wires for EHV Transmission Lines in Strong-Wind Areas

Mitigation of Fretting Fatigue Damage in Blade and Disk Pressure Faces With Low Plasticity Burnishing

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