Extraction of stress intensity factors for 3D small fatigue cracks using digital volume correlation and X-ray tomography

Lachambre, Joël; Réthoré, Julien; Weck, Arnaud; Buffière, Jean‐Yves

doi:10.1016/j.ijfatigue.2014.03.022

Cited by 48 publications

(25 citation statements)

References 40 publications

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“…To overcome this difficulty, a dedicated GPU implementation has been set up that can handle several million degrees of freedom problems within an acceptable time (less than 10 minutes) [122]. When analyzing localized phenomena (e.g., strain localization and cracks), special care should be exercised to properly capture high local strain gradients [214] or displacement discontinuities [94,119]. It will be illustrated in Section 3.5.4.…”

Section: Regularized Dvcmentioning

confidence: 99%

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Digital Volume Correlation: Review of Progress and Challenges

et al. 2018

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3D imaging has become popular for analyzing material microstructures. When time lapse series of 3D pictures are acquired during a single experiment, it is possible to measure displacement fields via digital volume correlation (DVC), thereby leading to 4D results. Such ForewordThe present paper aims at reviewing the major developments in Digital Volume Correlation (DVC) over the past ten years. It follows the first review on DVC that was published in 2008 by its pioneer [11]. In the latter, the interested reader will find all the general principles associated with what is now called local DVC. They will not be recalled hereafter. In such approaches the region of interest is subdivided into small subvolumes that are independently registered. In addition to its wider use with local approaches, DVC has been extended to global approaches in which the displacement field is defined in a dense way over the region of interest. Kinematic bases using finite element discretizations have been selected. To further add mechanical content, elastic regularization has been introduced. Last, integrated approaches use kinematic fields that are constructed from finite element simulations with chosen constitutive equations. The material parameters (and/or boundary conditions) then become the quantities of interest.These various implementations assume different degrees of integration of mechanical knowledge about the analyzed experiment. First and foremost, DVC can be considered as a stand-alone technique, which has seen its field of applications grow over the last ten years. In this case the measured displacement fields and post-processed strain fields are reported. With the introduction of finite element based DVC, the measured displacement field is continuous. It is also a standalone technique. However, given the fact that it shares common kinematic bases with numerical simulations, it can be easily combined with the latter. One route is to require local satisfaction of equilibrium via mechanical regularization. Another route is to fully merge DVC analyses and numerical simulations via integrated approaches. Different examples will illustrate how these various integration steps can be tailored and what are the current challenges associated with various approaches.

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Section: Regularized Dvcmentioning

confidence: 99%

“…Short fatigue cracks were analyzed in cast magnesium alloy with the measured bulk displacement fields [147]. Stress intensity factor profiles were extracted from the analysis of a short fatigue crack in cast iron [119]. Such analyses are very challenging since the graphite nodules interact with short cracks.…”

Section: Introductionmentioning

confidence: 99%

Digital Volume Correlation: Review of Progress and Challenges

et al. 2018

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“…Combining this technique with numerical simulation, it is possible to obtain local crack driving forces and closure levels. Latest achievements in the investigation of fatigue cracks are studies of 3D semi-elliptical surface cracks by in situ tomography [72] and 3D observation of real casting defects [25].…”

Section: Fatigue Crack Growthmentioning

confidence: 99%

Micromechanisms of fracture in nodular cast iron: From experimental findings towards modeling strategies – A review

Hütter

Zybell

Kuna

2015

Engineering Fracture Mechanics

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“…In this work, the comparisons with finite element computations were only performed regarding the evolution of voids. Rannou et al (2010) and Lachambre et al (2015) studied 3D fatigue crack growth in cast iron and used synchrotron XR-μCT combined with in situ experiments to characterize the actual geometry of the 3D crack. This geometry was used as an input in XFEM (Moës et al, 1999) simulations to estimate the Stress Intensity Factors at the crack front.…”

mentioning

confidence: 99%

Initiation and propagation of complex 3D networks of cracks in heterogeneous quasi-brittle materials: Direct comparison between in situ testing-microCT experiments and phase field simulations

Nguyen

Yvonnet

Bornert

et al. 2016

Journal of the Mechanics and Physics of Solids

110

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Keywords:Micro cracking Quasi-brittle Heterogeneous material Phase-field method Gradient damage model Voxel-based models In situ testing X-ray microtomography Digital volume correlation a b s t r a c tWe provide the first direct comparisons, to our knowledge, of complex 3D micro cracking initiation and propagation in heterogeneous quasi-brittle materials modelled by the phase field numerical method and observed in X-ray microtomography images recorded during in situ mechanical testing. Some material parameters of the damage model, including the process zone (internal) length, are identified by an inverse approach combining experimental data and 3D simulations. A new technique is developed to study the micro cracking at a finer scale by prescribing the local displacements measured by digital volume correlation over the boundary of a small sub-volume inside the sample during the numerical simulations. The comparisons, performed on several samples of lightweight plaster and concrete, show a remarkable quantitative agreement between the 3D crack morphology obtained by the model and by the experiments, without any a priori knowledge about the location of the initiation of the cracks in the numerical model. The results indicate that the crack paths can be predicted in a fully deterministic way in spite of the highly random geometry of the microstructure and the brittle nature of its constituents.

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Extraction of stress intensity factors for 3D small fatigue cracks using digital volume correlation and X-ray tomography

Abstract: International audienc

Cited by 48 publications

References 40 publications

Digital Volume Correlation: Review of Progress and Challenges

Digital Volume Correlation: Review of Progress and Challenges

Micromechanisms of fracture in nodular cast iron: From experimental findings towards modeling strategies – A review

Initiation and propagation of complex 3D networks of cracks in heterogeneous quasi-brittle materials: Direct comparison between in situ testing-microCT experiments and phase field simulations

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