Elastic-plastic crack-tip-field numerical analysis integrated with moire interferometry

Sivaneri, N. T.; Xie, Y. P.; Kang, Bruce S.

doi:10.1007/bf00042197

Cited by 12 publications

(1 citation statement)

References 9 publications

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“…The most detailed studies on fatigue crack tip plastic zone have been developed using the finite element method. For instance, Paul and Tarafder 23 identified the cyclic and monotonic plastic zone numerically, in a C‐Mn grade 6 steel SA333, observing how permanent deformations were accumulated in the plastic region. Some early 2D finite element models (FEM) investigated the effect on various materials at different loading levels, relating the size of the plastic zone to crack closure effects 24 .…”

Section: Introductionmentioning

confidence: 99%

Characterisation of the crack tip plastic zone in fatigue via synchrotron X‐ray diffraction

Carrera

Cruces

Kelleher

et al. 2022

Fatigue Fract Eng Mat Struct

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This paper describes a new methodology for characterising the plastic zone ahead of a fatigue crack. This methodology is applied to a set of experimental data obtained by synchrotron X-ray diffraction on a bainitic steel compact tension specimen. The methodology is based on generating the equivalent Von Mises strain field from the X-ray experimental elastic strain maps. Based on the material response, a threshold is then applied on the equivalent strain maps to identify the size and shape of the plastic zone. The experimental plastic zone lies between the plane strain and plane stress Westergaard's bounds but closer to the plane strain theoretical prediction confirming that the volume analyzed is predominantly subjected to plane strain conditions. However, the observed plastic zone has a somewhat flatter shape, extending further from the crack plane but less extended in the crack growing direction.

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Section: Introductionmentioning

confidence: 99%

Characterisation of the crack tip plastic zone in fatigue via synchrotron X‐ray diffraction

Carrera

Cruces

Kelleher

et al. 2022

Fatigue Fract Eng Mat Struct

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Elastoplastic crack analysis by boundary integral method and surface spectrum measurement

Sládek

Držík

1995

Int J Fract

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The paper describes a hybrid experimental-numerical technique for elastoplastic crack analysis. It consists of the experimental surface spectrum measurement of plastic strains ahead the crack tip and the boundary element method (BEM). The light scattering method is used to measure the power density spectrum from which the values of plastic strains are obtained by comparison with a calibration experiment on the same material. Plastic strains obtained experimentally are conveniently used for the calculation of unknown boundary displacement or traction vectors by the boundary element method. Instead of an iterative solution of the boundary integral equations in pure numerical solution, the boundary unknowns are computed once for a required loading level. Also asymptotic d~stribution of strains or stresses is not needed in the evaluation of the domain integral for the BEM formulation in the vicinity of the crack tip. Significant CPU time saving is achieved in comparison with the pure BEM solution. The method presented is illustrated by the example for a three point bending specimen with an edge crack.

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An intelligent hybrid method to automatically detect and eliminate experimental measurement errors for linear elastic deformation fields

Nishioka

Kurio

Nakabayashi

2000

Experimental Mechanics

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ABSTRACT--In a previous study, to minimize or eliminate the errors and noises associated with a full-field experimental measurement and subsequent fringe analysis such as moir6 interferometry, the authors derived a variational principle minimizing the experimental measurement errors. Furthermore, on the basis of this variational principle, the authors developed an intelligent hybrid method. In several test simulations, the method has demonstrated the automatic detection and elimination of randomly incorporated errors into known correct finite element displacement fields. In this study, a fringe analysis method is developed together with the twodimensional fast Fourier transform method. Then, experimentally recorded moir6 fringe patterns are analyzed by the fringe analysis method. The conventional and intelligent hybrid analyses are carried out using the analyzed fringe information as input data. The present method verifies the automatic detection of experimental errors and noises, and the simultaneous automatic elimination of those experimental errors. This method also makes it possible to obtain a fairly smooth visualization of higher order information such as the stress and strain distributions.KEY WORDS--Hybrid experimental-numerical method, intelligent measurement, noise elimination, variational principle, moir6 interferometry

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Elastic-plastic crack-tip-field numerical analysis integrated with moire interferometry

Cited by 12 publications

References 9 publications

Characterisation of the crack tip plastic zone in fatigue via synchrotron X‐ray diffraction

Characterisation of the crack tip plastic zone in fatigue via synchrotron X‐ray diffraction

Elastoplastic crack analysis by boundary integral method and surface spectrum measurement

An intelligent hybrid method to automatically detect and eliminate experimental measurement errors for linear elastic deformation fields

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