scholarly journals Materials and mechanics of rate effects in brittle fracture. Progress report, October 1974--October 1975. [Stress intensity factors for crack propagation]

1975 ◽  
Author(s):  
S. Burns
Keyword(s):  
Stress Intensity ◽  
Brittle Fracture ◽  
Crack Propagation ◽  
Stress Intensity Factors ◽  
Progress Report ◽  
Intensity Factors ◽  
Rate Effects

Stress intensity factors in novel specimens for crack propagation under loading conditions II+III in polymers

2020 ◽  
Author(s):  
Ondrej Slávik ◽  
Pavel Hutař ◽  
Michael Berer ◽  
Anja Gosch ◽  
Tomáš Vojtek ◽  
...  
Keyword(s):  
Stress Intensity ◽  
Crack Propagation ◽  
Stress Intensity Factors ◽  
Loading Conditions ◽  
Intensity Factors

Analysis of Crack Propagation in Roller Bearings Using the Boundary Integral Equation Method—A Mixed-Mode Loading Problem

1988 ◽  
Vol 110 (3) ◽  
pp. 408-413 ◽  
Author(s):  
L. J. Ghosn
Keyword(s):  
Integral Equation ◽  
Stress Intensity ◽  
Crack Propagation ◽  
Boundary Integral Equation ◽  
Stress Intensity Factors ◽  
High Speed ◽  
Roller Bearing ◽  
Boundary Integral ◽  
Boundary Integral Method ◽  
Intensity Factors

Crack propagation in a rotating inner raceway of a high-speed roller bearing is analyzed using the boundary integral method. The model consists of an edge plate under plane strain condition upon which varying Hertzian stress fields are superimposed. A multidomain boundary integral equation using quadratic elements was written to determine the stress intensity factors KI and KII at the crack tip for various roller positions. The multidomain formulation allows the two faces of the crack to be modeled in two different subregions making it possible to analyze crack closure when the roller is positioned on or close to the crack line. KI and KII stress intensity factors along any direction were computed. These calculations permit determination of crack growth direction along which the average KI times the alternating KI is maximum.

Crack Propagation in Rolling Line Contacts

1992 ◽  
Vol 114 (4) ◽  
pp. 690-697 ◽  
Author(s):  
H. Salehizadeh ◽  
N. Saka
Keyword(s):  
Stress Intensity ◽  
Crack Propagation ◽  
Stress Intensity Factors ◽  
Mode Ii ◽  
Pure Mode ◽  
Intensity Factors ◽  
Crack Face ◽  
Normal Loading ◽  
Line Contacts ◽  
Crack Growth Model

The stress intensity factors for short straight and branched subsurface cracks subjected to a Hertzian loading are calculated by the finite element method. The effect of crack face friction on stress intensity factors is considered for both straight and branched cracks. The calculations show that the straight crack is subjected to pure mode II loading, whereas the branched crack is subjected to both mode I and mode II, with ΔKI/ΔKII < 0.25. Although KI is small, it strongly influences KII by keeping the branched crack faces apart. Based on the ΔKII values and Paris’s crack growth model, the number of stress reversals required to grow a crack in a rolling component from an initial threshold length to the final spalling length was estimated. It was found that the crack propagation period is small compared with the expected bearing fatigue life. Therefore, crack propagation is not the rate controlling factor in the fatigue failure of bearings operating under normal loading levels.

The Calculation of Stress Intensity Factors and the Analysis of Propagation Characteristic of Crack at Hole

2011 ◽  
Vol 250-253 ◽  
pp. 1856-1861
Author(s):  
Li Jun Lu ◽  
Jian Ping Liu ◽  
Zhong Mei Li
Keyword(s):  
Stress Intensity ◽  
Crack Propagation ◽  
Stress Intensity Factors ◽  
Propagation Velocity ◽  
Propagation Characteristic ◽  
Propagation Model ◽  
Intensity Factors ◽  
Crack Propagation Velocity ◽  
Guyed Mast ◽  
Shape And Size

This paper focusing on the crack at hole of guyed-mast’s ear-plate connecting cables and shaft of guyed-mast, adopting two degree of freedom crack propagation model, track the crack propagation according to the increment of the deepest point and the surface point on the crack front of crack at hole of guyed-mast’s ear-plate. The stress intensity factors of I,II and III type crack with given shape and size have been calculated via finite element method, and a numerical method of calculating stress intensity factors with any shape and size crack has been proposed; furthermore according to modified I, II and III type compound crack propagation velocity formula on the basis of Paris crack propagation velocity formula, we analyzed the changing of crack shape parameter a/c with crack size parameter a/T of crack at hole of ear-plate connecting cable and shaft of guyed-mast by numerical integration method and obtained the propagation characteristic.

On the Influence of the Corner Singularity on Kinking Mixed-Mode Crack Propagation

2007 ◽  
Vol 348-349 ◽  
pp. 585-588
Author(s):  
Henning Schütte ◽  
Kianoush Molla-Abbasi
Keyword(s):  
Stress Intensity ◽  
Crack Propagation ◽  
Crack Growth ◽  
Stress Intensity Factors ◽  
Mixed Mode ◽  
Small Scale ◽  
Intensity Factors ◽  
Plastic Energy ◽  
Mixed Mode Crack ◽  
The Impact

The aim of the presentation is to highlight the influence of the kink, developing at the beginning of mixed-mode crack growth, on the propagation behavior of the crack. Le et al. [1] have shown that the variational principle of a body containing a crack results in the principle of maximum energy release rate incorporating the stress intensity factors of the kinked crack. Here the influence of the kink and the kinking angle, resulting in a singular field around the corner, on the crack growth is analyzed. The generalized stress intensity factors at the kinks corner are computed with the help of a FEM strategy. The influence of these on the T-stresses and the plastic energy dissipated at the kink is determined using a small scale yielding approach. The impact of these results on mixed-mode crack propagation is discussed.

Effect fracture resistance on retardation of crack growth

2015 ◽  
Vol 6 (4) ◽  
pp. 510-521
Author(s):  
Jirí Behal ◽  
Petr Homola ◽  
Roman Ružek
Keyword(s):  
Fatigue Crack ◽  
Stress Intensity ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Aluminium Alloy ◽  
Crack Growth ◽  
Stress Intensity Factors ◽  
High Stress ◽  
Intensity Factors ◽  
Content Type

Purpose – The prediction of fatigue crack growth behaviour is an important part of damage tolerance analyses. Recently, the author’s work has focused on evaluating the FASTRAN retardation model. This model is implemented in the AFGROW code, which allows different retardation models to be compared. The primary advantage of the model is that all input parameters, including those for an initial plane-strain state and its transition to a plane-stress-state, are objectively measured using standard middle-crack-tension M(T) specimens. The purpose of this paper is to evaluate the ability of the FASTRAN model to predict correct retardation effects due to high loading peaks that occur during variable amplitude loading in sequences representative of an aircraft service. Design/methodology/approach – This paper addresses pre-setting of the fracture toughness K R (based on J-integral J Q according to ASTM1820) in the FASTRAN retardation model. A set of experiments were performed using specimens made from a 7475-T7351 aluminium alloy plate. Loading sequences with peaks ordered in ascending-descending blocks were used. The effect of truncating and clipping selected load levels on crack propagation behaviour was evaluated using both experimental data and numerical analyses. The findings were supported by the results of a fractographic analysis. Findings – Fatigue crack propagation data defined using M(T) specimens made from Al 7475-T7351 alloy indicate the difficulty of evaluating the following two events simultaneously: fatigue crack increments after application of loads with maximum amplitudes that exceeded J Q and subcritical crack increments caused by loads at high stress intensity factors. An effect of overloading peaks with a maximum that exceeds J Q should be assessed using a special analysis beyond the scope of the FASTRAN retardation model. Originality/value – Measurements of fatigue crack growth on specimens made from 7475 T7351 aluminium alloy were carried out. The results indicated that simultaneously evaluating fatigue crack increments after application of the load amplitude above J Q and subcritical increments caused by the loads at high stress intensity factors is difficult. Experiments demonstrated that if the fatigue crack reaches a specific length, the maximal amplitude load induces considerable crack growth retardation.

Benchmark of Finite Elements and Extended-Finite Elements Methods for Stress Intensity Factors and Crack Propagation

2018 ◽  
Author(s):  
Rémi Lacroix ◽  
Axelle Caron ◽  
Sandrine Dischert ◽  
Hubert Deschanels ◽  
Moïse Pignol
Keyword(s):  
Finite Element ◽  
Stress Intensity ◽  
Finite Elements ◽  
Crack Propagation ◽  
Stress Intensity Factors ◽  
Power Plants ◽  
Classical Case ◽  
Finite Elements Method ◽  
Intensity Factors ◽  
Numerical Predictions

Stress intensity factors (SIFs) are a major feature in regulatory analyses of Nuclear Power Plants (NPP) components, as they allow to rule on the acceptability of defects when compared to a critical experimental value (K1c). Simplified and robust evaluations of SIFs have been provided in major regulations standards for cracks having usual geometries and locations in major components. However, their evaluations still require a significant effort in the case of important deviations of the geometry of cracks regarding the usual semi-elliptical shape, or in the case of specific geometries of components, and specific locations of cracks in components. In these cases, time-consuming Finite Element meshes must be constructed, either manually or using semi-automatical tools, to represent the components and its defect(s). This method can become particularly costly, especially in the case of fatigue crack propagation. The eXtended-Finite Elements Method (X-FEM) has been proposed to overcome this issue. The representation of the defect is carried out by the level-set method, and specific enrichment functions are used to represent the solution near the crack surface and the crack front. This paper proposes a benchmark of numerical predictions of stress intensity factors using SYSTUS software [5]. It will be based on: a) Available analytical solutions; b) Classical Finite Element method; c) EXtended-Finite Elements Method. The classical case of a circular and elliptical crack in a semiinfinite body is first presented. Then the case of a circumferential crack in a valve under a thermo-mechanical loading is analyzed. The accuracy of the different methods is then compared and discussed.

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