The Elastic Stress Field around a Crack Tip

Sun, C. T.; Jin, Zhaoyu

doi:10.1016/b978-0-12-385001-0.00003-1

Cited by 16 publications

(15 citation statements)

References 7 publications

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“…2(a). For the coupled criterion the stress can be calculated on the (Ox) axis (y = 0) measured from the crack tip with the following equation (Sun and Jin, 2012):…”

Section: Mode I Tensile Opening In An Infinite Planementioning

confidence: 99%

Toughness or strength? Regularization in phase-field fracture explained by the coupled criterion

Molnár

Doitrand

Estevez

et al. 2020

Theoretical and Applied Fracture Mechanics

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In recent years the phase-field method and the coupled energy and stress-based criterion have attracted much attention due to their adaptability in modeling fractures. Both approaches have been successfully used to determine crack initiation and have compared well with real-life experiments. The phase-field method diffuses the crack surface into the volume of the solid, thus making the solution viable through variational techniques. The diffusion is controlled by an internal length scale, which is primarily considered to be a numerical aid without any real physical meaning. In this paper, we question the consideration that the internal length is only a numerical parameter, and assess its mechanical significance with the help of the coupled criterion. Through elaborate benchmark examples, the correlation between the two methods is demonstrated based on the critical loading, the crack topology, and the crack arrest length. We reveal that independently of the chosen aspect, the phase-field approach and the coupled criterion present excellent correspondence. We show that the correlation between tensile strength and length scale is unique for the standard phase-field formulation. Interestingly, we find that both stress and energy criteria are satisfied in the phase-field fracture, and this is explained by demonstrating the alteration in global energy release rate due to the regularization introduced by the smeared model.

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“…2(a). For the coupled criterion the stress can be calculated on the (Ox) axis (y = 0) measured from the crack tip with the following equation (Sun and Jin, 2012):…”

Section: Mode I Tensile Opening In An Infinite Planementioning

confidence: 99%

Toughness or strength? Regularization in phase-field fracture explained by the coupled criterion

Molnár

Doitrand

Estevez

et al. 2020

Theoretical and Applied Fracture Mechanics

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“…However, body-centered cubic (BCC) materials are not close packed and the slip moves in the most atom-dense {110} planes, which have a lower atomic packing factor (APFα = 0.68) than that of FCC materials (APFγ = 0.74). Hence, a higher critical shear stress is required to initiate cracks in BCC structures than in FCC ones because in the initial stage, fatigue cracks initiate and propagate at the PSB-matrix interfaces under the shear stress in fracture Mode II, which acts parallel to the plane of the crack and perpendicular to the crack front [86,87]. Most studies concerning BCC materials were conducted using pure metals, as impurities introduced by alloying elements increase the complexity of the dislocation behavior.…”

Section: Microstructural Evolution After Fatigue Testsmentioning

confidence: 99%

High-Cycle, Low-Cycle, Extremely Low-Cycle Fatigue and Monotonic Fracture Behaviors of Low-Carbon Steel and Its Welded Joint

Kim

Hwang

2019

Materials

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Low-carbon steels are commonly used in welded steel structures and are exposed to various fatigue conditions, depending on the application. We demonstrate that the various transitions in the fracture mode during fatigue testing can be distinguished by their different cyclic response curves and microstructural features after fracture. Fractography, surface damage micrographs, and microstructural evolution clearly indicated the transition of the fracture modes from high-cycle to low-cycle, extremely low-cycle fatigue, and monotonic behavior. The high-cycle fatigue mode showed initial cyclic softening, followed by cyclic stabilization, and showed inclusion-induced crack initiation at fish-eyes, while the low-cycle fatigue mode showed initial cyclic hardening followed by cyclic stabilization, where fractography images showed obvious striations. In addition, the extremely low-cycle fatigue mode showed no cyclic stabilization after initial cyclic hardening, which was characterized by quasi-cleavage fractures with a few micro-dimples and transgranular cracking, while the monotonic fracture mode predominantly showed micro-dimples.

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“…In the absence of tearing resistance data for the swage weld geometry, the methodology described above can only be applied when using the Linear Elastic Fracture Mechanics (LEFM) theory and assumptions (Sun and Jin, 2012). In other words, the small-scale yielding assumption is valid for this approach.…”

Section: Theory and Motivationmentioning

confidence: 99%