Crack front curvature: Influence and effects on the crack tip fields in bi-dimensional specimens

Camas, D.; Garcia-Manrique, J.; González-Herrera, Antonio

doi:10.1016/j.ijfatigue.2012.05.012

Cited by 51 publications

(21 citation statements)

References 25 publications

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“…In recent studies developed by the present authors, an ultra‐mesh of 40 to 80 divisions of thickness was necessary. In that work, we present the influence of this parameter through the analysis of the evolution of the plastic zone in a fracture problem.…”

Section: Minimum Element Sizementioning

confidence: 99%

“…There is no theoretical solution near the crack front in an elastic–plastic specimen that identifies the intermediate states between the inside and the surface. This transition was studied in previous work through the analysis of the evolution of two parameters: the plastic zone size and the stress evolution along the thickness. Due to the conclusions of this paper, plane strain relation was assumed most suitable .…”

Section: K and J‐integral Calculation 3‐d Parameter Analysismentioning

confidence: 99%

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Study of the stress intensity factor analysis through thickness: methodological aspects

Garcia-Manrique

Camas

González-Herrera

2017

Fatigue Fract Eng Mat Struct

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This paper is focused on the methodological aspects of the numerical study of stress intensity factor (SIF) evolution through thickness. The work evaluates the modelling of an Al‐alloy 2024‐T351 CT specimen under mode I nominal loading in fracture. No plastic wake effect is introduced to separate the influence of plasticity‐induced crack closure near the surface. Numerical models have shown the complexity 3‐D behaviour in the vicinity of the crack front and finite element methods (FEM) are widely used in these problems with interesting results. However, there is a lack of literature support in many simplifying assumptions. In previous studies, authors have analysed some issues as the evolution of the plastic zone, the crack closure stress or the SIF. The current work attempts to describe and justify the key aspects of the methodology developed to address these problems by the FEM. A huge effort has been made to study main parameters involved and their influence in the results, especially in order to properly capture the SIF distribution along the thickness. Recommendations about mesh density are provided, and the main procedures to obtain K are discussed.

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Section: Minimum Element Sizementioning

confidence: 99%

Section: K and J‐integral Calculation 3‐d Parameter Analysismentioning

confidence: 99%

Study of the stress intensity factor analysis through thickness: methodological aspects

Garcia-Manrique

Camas

González-Herrera

2017

Fatigue Fract Eng Mat Struct

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“…Subsequently, many researchers have attempted to tie these three‐dimensional effects to the experimental evidences. One typical example is the influence of 3D vertex (or corner) singularities on the evolution of the fatigue crack front shape and fatigue crack growth rates in plates of various thicknesses, which was a topic of intensive recent studies by a number of researchers …”

Section: Introductionmentioning

confidence: 99%

“…One typical example is the influence of 3D vertex (or corner) singularities on the evolution of the fatigue crack front shape and fatigue crack growth rates in plates of various thicknesses, which was a topic of intensive recent studies by a number of researchers. [20][21][22] Many analytical, numerical and experimental investigations in the past have focused on the characterisation of the three-dimensional stress and displacement fields near a crack tip. These include a pioneering study of Hartranft and Sih on the application of the Eigen Function Expansion approach to three-dimensional crack problems, 23 which was further extended by Omer and Yosibash, 24 an analytical solution for a semi-infinite crack 25 and a semi-analytical approach for the analysis of three-dimensional crack problems based on the distributed dislocation technique 8 and the threedimensional solution for an edge dislocation.…”

Section: Introductionmentioning

confidence: 99%

Effect of vertex singularities on stress intensities near plate free surfaces

Kotousov

Berto

2015

Fatigue Fract Eng Mat Struct

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The stress intensity factor (SIF) distribution along the front of a through-the-thickness crack is significantly influenced by the presence of the 3D corner (vertex) singularities. All past 3D finite element studies indicated that for mode I, SIF rapidly decreases near the free surface and for mode II, it sharply increases. From the previous numerical simulations, it is unclear what the limiting values of SIF near the surface are and whether these values are infinite or bounded at the vertex point. In this paper, we conduct a careful finite element study and propose a theoretical equation, which describes the SIF behaviour near the vertex. We demonstrate that the asymptotic behaviour of SIF near the surface is governed by the difference in the strength of the corner and edge singularities. Furthermore, we validate our numerical approach and calculations by utilising the invariant properties of J-integral

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“…In addition to the effects of plasticity, graphite cast irons are known to exhibit crack closure effects due to material roughness [22] or detachment of graphite particles [13]. Furthermore, Camas et al [9] showed the crack curvature can increase the plastic area in the case of 3D finite element computations. Thus, if the curvature is not taken into account, it is possible that the plastic zone and therefore the wake are underestimated.…”

Section: Comparison With the Projective Approachmentioning

confidence: 99%

Plastic zone evolution during fatigue crack growth: Digital image correlation coupled with finite elements method

Hosdez

Langlois

Witz

et al. 2019

International Journal of Solids and Structures

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et al.. Plastic zone evolution during fatigue crack growth: Digital image correlation coupled with finite elements method. International Journal of Solids and Structures, Elsevier, 2019, 171, pp.Abstract Nonlinearities effects at the crack tip, due to the elastic-plastic material behavior, impact the crack growth rate and path. This paper is devoted to the study of the plastic zone evolution in the crack tip region. The methodology relies on coupling an elastic-plastic Finite Elements Method (FEM) model and experimental displacements measured by Digital Image Correlation (DIC). These latter are introduced as Dirichlet boundary conditions in the finite elements analysis. The considered FEM domain is constant, i.e. the same mesh with a centered crack is moved to each new crack tip position deduced from DIC. The new boundary conditions are updated and the residual stresses and plastic strains of the former computation are interpolated and actualized on the mesh shifted to the new crack tip position in order to incorporate them in the numerical model. The coupling method allowed applying experimental boundary conditions in order to be as close as possible to real experimental conditions and to observe the plasticity evolution from small to large scale yielding conditions. A fatigue test was conducted to validate the proposed approach. The identification residues are proved to be lower than those obtained with an experimental displacements projection onto Williams' series basis, which is a method commonly used with DIC. The coupling results present an attractive similarity with Irwin's model regardless of the crack length. Thus, the definition of the mask needed for the displacements fields projection on Williams' model can be deduced with a reliable estimate of Irwin's plastic radius.

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Crack front curvature: Influence and effects on the crack tip fields in bi-dimensional specimens

Cited by 51 publications

References 25 publications

Study of the stress intensity factor analysis through thickness: methodological aspects

Study of the stress intensity factor analysis through thickness: methodological aspects

Effect of vertex singularities on stress intensities near plate free surfaces

Plastic zone evolution during fatigue crack growth: Digital image correlation coupled with finite elements method

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