Evaluation of crack-tip fields from DIC data: A parametric study

Mokhtarishirazabad, Mehdi; López-Crespo, P.; Moreno, B.; Lopez-Moreno, A.; Zanganeh, M.

doi:10.1016/j.ijfatigue.2016.03.006

Cited by 77 publications

(50 citation statements)

References 39 publications

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“…In view of this, the conclusion would be that results become more reliable for >2 terms and that the best SIF predictions (minimum error) are obtained when α = 0º when using 3 to 6 terms in Williams' expansion. That is, the best results in terms of estimating the SIF are obtained by collecting data not only ahead of the crack tip but also from the crack wake region, in agreement with previous studies [27]. …”

Section: Number Of Terms Size and Shape Of The Area Of Interestsupporting

confidence: 90%

“…Key parameters influencing the K estimation with the current scheme were identified previously [26,27]. These include the number of terms used in Williams' expansion, the size and shape of the area of interest (AOI) used for the fitting, the influence of the plastic zone and the number of experimental data points considered.…”

Section: Parametric Studymentioning

confidence: 99%

“…2). The amount of data collected in the crack wake has been previously identified as critically affecting the SIF estimation [27]. Fig.…”

Section: Number Of Terms Size and Shape Of The Area Of Interestmentioning

confidence: 99%

See 2 more Smart Citations

Mid-thickness studies of the stress intensity factor in the bulk of bainitic steel

López-Crespo

Vazquez-Peralta

Simpson³

et al. 2017

Frattura Ed Integrità Strutturale

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ABSTRACT. The current work aims at estimating the stress intensity factor deep inside the bulk from elastic strain data measured by synchrotron X-ray diffraction. Key features affecting the evaluation of the stress intensity factor are the number of terms in the analytical model describing the crack tip field, the extension and position of the area of interest of the experimental data, the effect of the experimental data collected within the plastic zone and the number of elastic strain data points used. Here a parametric study of these features is presented in terms of their influence for the stress intensity factor determination. It was found that 3 or 4 terms in Williams' expansion is often sufficient; the data should be collected from across the full range of angles around the crack tip; and the number of points/number of terms should be greater than 40.

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Section: Number Of Terms Size and Shape Of The Area Of Interestsupporting

confidence: 90%

Section: Parametric Studymentioning

confidence: 99%

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Mid-thickness studies of the stress intensity factor in the bulk of bainitic steel

López-Crespo

Vazquez-Peralta

Simpson³

et al. 2017

Frattura Ed Integrità Strutturale

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“…In this work, this pattern with random grey intensity distribution was obtained by scratching the sample surface with abrasive SiC sand papers grades 240, 380 and 800 [10], [11] for better imaging of the crack tip [12]. An 8-bit 2452x2052 pixels CCD camera with the maximum frame rate of 12 was used for taking images and recommendations from previous analyses were followed [13]. The experimental setup was similar to the one used previously [14].…”

Section: Materials Al 2024 and Methods Of Measurementmentioning

confidence: 99%

Williams expansion-based approximation of the stress field in an Al 2024 body with a crack from optical measurements

Seitl¹,

Malíková²,

Sobek³

et al. 2017

Frattura Ed Integrità Strutturale

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ABSTRACT.A study on the approximation of the stress field in the vicinity of crack tip in a compact tension specimen made from Al 2024-T351 is presented. Crack tip stress tensor components are expressed using the linear elastic fracture mechanics (LEFM) theory in this work, more precisely via its multi-parameter formulation, i.e. by Williams power series (WPS). Determination of coefficients of terms of this series is performed using a least squares-based regression technique known as over deterministic method (ODM) for which displacements data obtained experimentally via optical measurements are taken as inputs. The stress fields reconstructed based on the displacement data obtained experimentally by means of optical measurements are verified by means of the stress field approximations derived for the normalized CT specimen via hybrid elements.

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“…When using DIC results, the crack tip position is either determined manually or using a LEF mechanics analytical solution for the displacement field. Yoneyama et al use an iterative procedure based on the Newton‐Raphson method to determine the crack tip location and the mixed‐mode stress intensity factors at the same time.…”

Section: Introductionmentioning

confidence: 99%

Crack path tracking from full field measurements: A novel empirical methodology

Feld-Payet

Besnerais

Bonnand

et al. 2020

Strain

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The identification of crack growth models requires the knowledge of the crack path geometry and, in particular, of the crack tip position. The objective of the present paper is to provide a criterion for the detection of the crack tip position regardless of the loading conditions or the material behavior. The novelty of the proposed approach is its ability to provide a good estimation of the crack tip even when large plastic deformations occur. The proposed empirical criterion uses the evolution of the displacement gradient standard deviation along a potential crack path to locate the crack tip. It thus relies on full field measures that are relatively smooth while providing accurate displacement vectors even close to the lips. We successfully apply the proposed criterion in two cases of fatigue crack growth: A straight crack at high temperature and a curved crack at room temperature involving large plastic deformations.

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Evaluation of crack-tip fields from DIC data: A parametric study

Cited by 77 publications

References 39 publications

Mid-thickness studies of the stress intensity factor in the bulk of bainitic steel

Mid-thickness studies of the stress intensity factor in the bulk of bainitic steel

Williams expansion-based approximation of the stress field in an Al 2024 body with a crack from optical measurements

Crack path tracking from full field measurements: A novel empirical methodology

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