Crack propagation and the principal-tensile-stress criterion for mixed-mode loading

Vaughan, Henry

doi:10.1016/s0013-7944(97)00138-0

Cited by 17 publications

(5 citation statements)

References 5 publications

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“…According to Dae‐Jin Kim et al , 11 the direction of actual crack propagation on the friction plate of a brake disc is perpendicular to the maximum principal stress. In the multiaxial fatigue problem of brittle material, it was reported that the crack growth by theoretical calculations using principal tensile stress criterion by Vaughan 12 agreed well with experimental results 13 . In this study, we used maximum tangential stress criterion by Erdogan and Sih 14 which is the same criterion as the principal tensile stress criterion in the polar coordinates.…”

Section: Thermal Stress Analysissupporting

confidence: 54%

Fatigue life assessment for brake disc of railway vehicle

Kim¹,

Seok²,

Koo³

et al. 2009

Fatigue Fract Eng Mat Struct

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A B S T R A C T The brake disc of a railway should have stability. After long-term use, the brake disc may be seriously damaged by thermal fatigue cracks on the frictional surface. In this study, fatigue tests were carried out for a brake disc material (GC25). Furthermore, in order to determine the cause of the thermal fatigue cracks, contact pressure and thermal stress analyses were performed. From these results, the linear relation between temperature and stress variations was obtained, and the remaining life assessment of the brake disc of a railway vehicle was performed by using it.Keywords disc brake; fatigue life assessment; thermal stress analysis. N O M E N C L A T U R E I N T R O D U C T I O NAs the friction contact occurs between the brake disc of a railway vehicle and the pad pushing the revolving circular brake disc, the friction surface of the brake disc is repeatedly heated and cooled by the convection heat transfer between the surface and the ventilated holes during motion. 1 When it is heated by the frictional energy from braking, thermal expansion occurs. At this instant, because the thermal expansion is restrained by the structural shape of the brake disc and the braking pressure acting on the friction surface, compressive stress occurs on the friction surface. On the contrary, tensile stress occurs during cooling and the residual stress is distributed on the friction surface after cooling. If this braking process is repeated, thermal fatigue cracks occur on the friction surface. 2-4 Further, the wear resulting from repeated braking and the shape distortion caused by the thermal fatigue lead to an irregular contact surface between the brake disc and the lining and concentrate the friction heat on a local area. 5 Table 1 shows the replacement rate of the brake disc by thermal fatigue crack for the SAEMAUL train in Korea. 6 It has actually been reported that thermal fatigue cracks occur on the friction surface after the brake disc is used for 6 months, and the brake disc is often replaced at an interval of 2-3 years rather than that of 5-6 years, which is the typical life time, owing to the thermal fatigue. 6 The fatigue characteristic of the brake disc must be enhanced to resolve such problems, and for this, it is important to collect data on the variations in the temperature of an actual brake disc in operation. Furthermore, it is important to estimate the remaining life sufficiently in advance to prevent casualties resulting from the abrupt destruction of the brake disc. In this study, in order to determine the cause of thermal fatigue cracks, contact pressure and thermal stress analyses were performed. From these results, the linear relation between temperature and stress variations was obtained, and the remaining life assessment for the brake disc of a railway vehicle was performed by using it and the results of the fatigue tests for standard specimens.

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Section: Thermal Stress Analysissupporting

confidence: 54%

Fatigue life assessment for brake disc of railway vehicle

Kim¹,

Seok²,

Koo³

et al. 2009

Fatigue Fract Eng Mat Struct

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“…9 these maxima have been plotted against the segment 2 crack lengths for which they occur. Various sources in the literature [5,13] have proposed a theoretical value for K I as a 2 ! 0.…”

Section: Uniform Compression Resultsmentioning

confidence: 99%

Solution of the boundary value problem for a kinking crack in a bulk compression field

Porter

Hills

2002

The Journal of Strain Analysis for Engineering Design

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The solution of the boundary value problem for a macroscopic crack with a small wing crack, in a linear elastic brittle material, due to a bulk compressive stress field is considered. The crack, initially subject to pure mode II loading, propagates by kinking at its end and extending along a new trajectory, in the classical opening mode. The innovations of this paper are, firstly, the introduction of a free surface into an infinite plane solution, so that the original crack is an edge crack in a half-plane, and, secondly, the ability to consider rapidly varying stress gradients on both segments of the kinked crack. Solutions are presented for (a) an inclined crack in a uniform compressive field and (b) cracks subject to contact loading from a rigid punch loading the half-plane via a linear elastic interlayer.

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“…In this paper, cracks propagation in a solid, aluminum alloy 6061-T6, is been studied using the Fractal Geometry theory (FG). Firstly, toughness to fracture for failure Mode I was experimentally determined, and then, critical stress intensity factor was determined for Mode II using the results obtained by Henry Vaughan (1998). Then, direction of propagation was calculated in accordance with the LEFM theory (FM).Using the FG theory, fractal dimension of cracks has been determined for the studied aluminum, in order to relate it afterwards with facture properties of the material.…”

Section: Methods To Measure the Crack's Lengthmentioning

confidence: 99%

Fractal Cracks Propagation in Aluminum

Angel¹,

Velasco²

2013

MNSMS

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The theory of the fractal structure characterizing propagation of a crack through identification of its generator is presented. It's generating fractal, the peculiarities of its construction and the way to measure its segments are defined, and a theorem on the inverse scale property of such and other of the axial symmetry property of the fractal generator are presented and demonstrated. The theory is applied on 6061-T6 aluminum samples, using SENB probes. Direction of crack propagation and its fractal dimension are calculated numerically. Results obtained from modeling the direction of crack propagation through mechanics of elastic linear fracture and the one proposed here, called geometrical fractal fracture, are compared, thus developing the mirror case.

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Crack propagation and the principal-tensile-stress criterion for mixed-mode loading

Cited by 17 publications

References 5 publications

Fatigue life assessment for brake disc of railway vehicle

Fatigue life assessment for brake disc of railway vehicle

Solution of the boundary value problem for a kinking crack in a bulk compression field

Fractal Cracks Propagation in Aluminum

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