Experimental numerical method of loading estimation for structures with surface cracks

Разумовский, И. А.; Chernyatin, A. S.

doi:10.3103/s1052618809030066

Cited by 7 publications

(10 citation statements)

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“…The model includes regions with different structures of the element mesh and its sizes. Embedding the crack volume into the FE model is performed by means of the macro “crack,” which contains the following features: ‐ geometry of the curvilinear crack front can be arbitrary, but it should be smooth and lying in the crack plane (only coplanar crack is possible); ‐ crack front volume with mapped mesh of singular elements (quadratic elements with the midside nodes placed at the quarter points) is created along the crack front; ‐ the crack front can pass through several geometric volumes of the solid model. It is especially convenient for modeling of intersecting cracks; and ‐ the numerical procedure of the crack building supports the case of crack intersection at different positions. …”

Section: Model Of Fatigue Crack Propagation In the Presence Of Residumentioning

confidence: 99%

Fatigue surface crack propagation and intersecting cracks in connection with welding residual stresses

Chernyatin

Matvienko

Razumovsky

2018

Fatigue Fract Eng Mat Struct

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The effect of welding residual stress on surface fatigue crack propagation and fracture mechanics parameters of intersecting orthogonal cracks is discussed. The effect of welding residual stresses on fatigue propagation of the internal surface crack is analysed in the case of welded joint of the pipeline. To predict fatigue crack propagation, the modified Forman law taking into account the nonsingular T‐stress as the crack‐tip constraint has been employed. It is shown by means of numerical simulation (the software ANSYS and MATLAB) that welding residual stress and crack‐tip constraint effects lead to the semielliptical form of final configuration of the surface fatigue crack. Fracture mechanics parameters for intersecting surface cracks, namely, circular and semielliptical cracks in welded joint of the pipeline are also analysed by numerical simulation. It was concluded that welding residual stress intensifies the effect of intersecting orthogonal surface cracks on fracture mechanics parameters including the crack‐tip constraint.

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Section: Model Of Fatigue Crack Propagation In the Presence Of Residumentioning

confidence: 99%

Fatigue surface crack propagation and intersecting cracks in connection with welding residual stresses

Chernyatin

Matvienko

Razumovsky

2018

Fatigue Fract Eng Mat Struct

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“…:Registration of the displacement fields and data e i * establishment. Generation of the pseudo‐experimental (numerical) e i * data by means of a numerical experiment.Creation of a so‐called response bank (RB) that is a mathematical analogue of the FE model of the half‐space with the surface crack. It allows calculating the displacements e i in measurement points corresponding to e i * in case of arbitrary values of the searching parameters P = { b , s X , s Y }.Solution of a minimization problem.…”

Section: Statement Of the Problemmentioning

confidence: 99%

“…It should be noted that the use of a special objective function and subsequent solutions is needed in the case of complicated non‐homogenous stress field or mixed‐mode loading …”

Section: Computational Toolmentioning

confidence: 99%

“…The idea of minimization is well known, but the proposed method offers original features of mathematical, experimental, numerical and programming realization. The method can be applicable for simultaneous determination of different parameters of geometry, loading, material and so on in other inverse problems of solid mechanics . The data of e i are calculated by means of the finite element method (FEM), which allows carrying out a solution of the direct problem in the most general statement.…”

Section: Introductionmentioning

confidence: 99%

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A computational tool for estimating stress fields along a surface crack front

Chernyatin

Matvienko

Razumovsky

2014

Fatigue Fract Eng Mat Struct

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A combined experimental and computational method for determination of the singular and non‐singular stress terms along the front of the 3D surface crack is proposed. It is suggested to evaluate the terms by means of comprehensive comparison between deformation responses on the structure surface in the vicinity of the crack obtained experimentally and from numerical solutions of the corresponding boundary problem of solid mechanics. As the deformation response, a local displacement field caused by the formation of a small hole at the tip of the crack recorded by digital speckle pattern interferometry may be considered. The proposed approach allows defining such real parameters of the structure as the active load conditions in the crack region and crack sizes. These parameters are used to solve the direct problem and to determine the stress intensity factor KI and Txx‐, Tzz‐stresses along the surface crack front by means of an improved technique of their calculation. The approach accuracy and stability at different conditions have been proved by means of numerical simulation that examined half‐space with planar semi‐elliptical surface crack under biaxial loading. So, the potential applicability of the proposed method is demonstrated. The biaxiality effect on KI and Txx, Tzz is discussed.

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“…The problem can be solved by two steps. Firstly, the parameters b, σx, σy should be estimated by the following procedure [3]:  generation of the experimental data (ei * ) for the displacement fields; O T  creation so-called "response bank" which is mathematical analog of the FE model of the half-space with the surface crack. It allows calculating the values of the displacements in measurement points (ei) corresponding to ei * in case arbitrary values of the searching parameters (b, σx, σy);  solution of a minimization problem.…”

Section: Statement Of the Problemmentioning

confidence: 99%

Combining experimental and numerical analysis to estimate stress fields along the surface crack front

Chernyatin¹,

Matvienko²,

Razumovsky³

2013

Frattura Ed Integrità Strutturale

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Combining experimental and computational method for determination of the singular and the nonsingular stress terms along the front of the 3D surface crack is proposed. Evaluation of the terms is based on comprehensive comparison between deformation responses (for measurement points on the surface) obtained experimentally and from numerical solutions of the corresponding boundary problem of solid mechanics. The proposed approach allows carrying out an adequate and a comprehensive assessment of stress fields in the vicinity of the surface crack front.

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Experimental numerical method of loading estimation for structures with surface cracks

Cited by 7 publications

References 0 publications

Fatigue surface crack propagation and intersecting cracks in connection with welding residual stresses

Fatigue surface crack propagation and intersecting cracks in connection with welding residual stresses

A computational tool for estimating stress fields along a surface crack front

Combining experimental and numerical analysis to estimate stress fields along the surface crack front

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