Effects of Compressive Overloads on Fatigue Crack Growth

Hsu, T. M.; Lassiter, Leslie W

doi:10.2514/3.59807

Cited by 7 publications

(2 citation statements)

References 10 publications

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“…Second, the crack growth rates under the conjoint action of major and minor cycles have been successfully predicted in the past by summing the growth due to the different components of the loading, each having been determined in separate experiments using the appropriate constant amplitude loadings [14]. This is in keeping with the observations of Hsu and Lassite [15] who considered that crack growth rates in Ti-6Al-4V subjected to periodic underloads could be predicted by a linear summation procedure.…”

Section: Discussionmentioning

confidence: 99%

Fatigue Crack Growth Under the Conjoint Action of Major and Minor Stress Cycles

Hawkyard

Powell

Hussey

et al. 1996

Fatigue Fract Eng Mat Struct

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Fatigue crack growth rates in corner notched specimens of forged Ti-6Al-4V, used in the manufacture of rotating aero-engine components, have been measured for fatigue loadings that combine major and minor stress cycles. The loadings are simple representations of the flight cycle and the potential in-flight vibrations, each loading block consisting of high-frequency minor cycles superimposed on the major cycle dwell at maximum load. The crack growth rates are dependent on the number and stress ratio of the minor cycles, but only when they individually contribute to the growth of the crack. Estimates of the fatigue threshold values and near-threshold growth rates associated with the minor cycles have been made, all potential load history effects having been ascribed to the minor cycle component of the loading. Using this data, satisfactory crack propagation life predictions have been demonstrated for a wide range of test conditions involving the conjoint action of major and minor stress cycles. NOMENCLATUREda/dBlock = crack advance produced by a loading block consisting of a major [da/dN],,l = crack advance produced by the application of the total or overall [da/dN Jminor = average crack advance produced by the application of a minor stress cycle and several superimposed minor stress cycles stress cycle in a loading block cycle within a loading block n = number of minor cycles per major cycle; the cycle ratio R = stress ratio R,,, = stress ratio of the major cycle &, , , or = stress ratio of the minor cycle K, , = maximum stress intensity factor AKGfl = that part of the applied range of stress intensity factor associated with minor cycle crack growth AK,,,, = range of stress intensity factor associated with the total or overall stress cycle AKminor = range of stress intensity factor associated with the minor stress cycle AKfh,O.l) = derived fatigue threshold value for a minor cycle stress ratio of 0.9 A&, = fatigue threshold value derived from tests involving a combination of major and minor stress cycles

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Section: Discussionmentioning

confidence: 99%

Fatigue Crack Growth Under the Conjoint Action of Major and Minor Stress Cycles

Hawkyard

Powell

Hussey

et al. 1996

Fatigue Fract Eng Mat Struct

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“…Research has shown that fatigue crack closure is sensitive to loading pattern, test frequency, and test environment [3]. A single cycle of overload in a sequence of constant amplitude load cycles is known to induce retardation in crack growth rates, whereas an under load causes acceleration in crack growth rates [4,5]. Implications of crack closure are very many, especially when one considers the interactions that take place in a complex load sequence consisting of several overloads and under loads.…”

Section: Introductionmentioning

confidence: 99%

Crack closure stress estimation by decodable marker banding techniques and comparison of results with electron fractographic technique

Prakash

Sunder

2007

Proceedings of the Institution of Mechanical Engineers, Part L:

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A specially programmed marker load sequence was designed that permits unambiguous measurement of crack opening and crack closure stress from marker band spacing using both optical and scanning electron fractography. Crack growth tests using programmed marker loading sequence were carried out on single edge notch tension specimens made out of Al-Cu alloy 2014-T3 (BS: L73 equivalent) from crack initiation to failure and the fracture surface examined under optical and electron microscope. Reproducible marker band patterns on the fatigue fracture surface could be obtained using this method. Measured crack closure/opening stress values are observed to be consistent with known material behaviour. The marker banding technique can be applied over wider crack growth rate ranges compared to striation measurement technique, which is restricted to a small range of crack growth rate and in select materials. Quantitative fractography of the marker bands reveals a degree of load interaction under variable amplitude loading that requires further examination.

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Effects of compressive-compressive loads on spectrum fatigue crack growth

Hsu¹,

McGee²

1978

Int J Fract

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Effects of Compressive Overloads on Fatigue Crack Growth

Cited by 7 publications

References 10 publications

Fatigue Crack Growth Under the Conjoint Action of Major and Minor Stress Cycles

Fatigue Crack Growth Under the Conjoint Action of Major and Minor Stress Cycles

Crack closure stress estimation by decodable marker banding techniques and comparison of results with electron fractographic technique

Effects of compressive-compressive loads on spectrum fatigue crack growth

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