J-integral evaluation of a mode I crack in gradient nanocrystalline metals

Zhang, Zhennan; Yang, Fan; Liu, Yaping; Wang, Lihua

doi:10.1016/j.mtcomm.2020.101328

Cited by 4 publications

(3 citation statements)

References 44 publications

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“…6 Souiyah et al 7,8 employed the FEM to predict the crack propagation directions and the stress intensity factors (SIFs). Zhang et al 9 utilized the FEM to calculate the J-integral of a mode I crack in the gradient nanocrystalline metal. Khoei et al 10 proposed a polygonal FEM for the crack growth simulation.…”

Section: Introductionmentioning

confidence: 99%

Improved back propagation neural network based on the enrichment for the crack propagation

Wang,

Ye,

Yang

et al. 2023

Numerical Meth Engineering

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Numerical methods have been extensively applied to fracture mechanics, while they cannot simulate the problems without the mechanical models or constitutive equations. Artificial neural networks (ANNs) can be utilized to predict complex fracture problems, but these approaches require large amounts of data for the training. Therefore, in this paper, to combine the advantages of the numerical methods and the ANNs, an improved back propagation neural network (BPNN) is proposed by introducing the enrichment used in the numerical methods into the activation function utilized in the neural networks. The enrichment is able to represent the crack tip field which can accelerate the convergence. At the field near the crack tip, the improved BP solution can converge to the analytical solutions which validate the high accuracy of the proposed method. Without sufficient data, especially the data are missing in the near field of the crack tip, the improved BP method can also achieve high accuracy and convergence, while the conventional BP method may not converge to the predetermined error bound. Numerical simulations of the quasi‐static and fatigue crack problems demonstrate that the improved BP method can accurately predict the crack propagation and its growth rate with relatively little data.

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Section: Introductionmentioning

confidence: 99%

Improved back propagation neural network based on the enrichment for the crack propagation

Wang,

Ye,

Yang

et al. 2023

Numerical Meth Engineering

Self Cite

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“…21 Considerable attention has been paid to the influence of material properties such as the gradient of Young's modulus, the gradient of yield stress and so on. 22 However, the effect of the residual stress, which is inevitably induced during the mechanical surface treatment processes, is often ignored in the existing researches.…”

Section: Introductionmentioning

confidence: 99%

Evaluating the J-integral of mode I crack in gradient nanocrystalline metals with residual stress induced by surface mechanical treatment

Qiu

Yang

Zhang

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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In gradient nanocrystalline metals, the grain size variation usually comes with the compressive residual stress induced by mechanical surface treatments such as surface mechanical attrition and severe shot peening. This paper focused on the fracture of gradient nanocrystalline metals with the residual stress that is introduced during the mechanical surface treatment. The J-integral of a mode I crack in the gradient nanocrystalline metal with different residual stress was calculated using finite element method. ABAQUS/Python scripts were developed to automatically create the gradient material, exert the residual stress and calculate the J-integral. By employing the empirical residual stress formula of sinusoidal decay type, a parametric study was carried out to investigate the effects of two characteristic features of residual stress, i.e., the magnitude and the compressive zone depth, on the calculated J-integral. The results reveal that J-integral is significantly influenced by the residual stress. Specifically, the J-integral will decrease as the magnitude of residual stress increases. As the compressive zone depth increases, the J-integral first decreases and then increases. This indicates that the induced residual stress, along with the surface grain size variation, contributes jointly to the enhanced toughness of the gradient nanocrystalline metals.

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“…Being based on an energy balance approach, it can also be used as an elastic–plastic energy release rate (under certain restrictions). J integral is still used widely in several state-of-the-art papers, e.g., [ 4 , 5 , 6 ]. Generally, the determination of the J integral for a cracked body loaded with a certain stress pattern is not simple and the solution of this problem requires, with the exception of some simple bodies and crack configurations, employment of computerized numerical methods.…”

Section: Introductionmentioning

confidence: 99%

Comparison of J Integral Assessments for Cracked Plates and Pipes

et al. 2021

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The purpose of this article is to compare two predictive methods of J integral assessments for center-cracked plates, single-edge cracked plates and double-edge cracked plates produced from X52 and X70 steels, and a longitudinally cracked pipe produced from X70 steel. The two methods examined are: the GSM method and the Js procedure of the French RCC-MR construction code, designated here as the FC method. The accuracy of J integral predictions by these methods is visualized by comparing the results obtained with the “reference” values calculated by the EPRI method. The main results showed that both methods yielded similar J integral values, although in most cases, the GSM predictions were slightly more conservative than the FC predictions. In comparison with the “reference” values of the J integral, both methods provided conservative results for most crack configurations, although the estimates for cracks of a relative length smaller than 1/8 were not found to be so conservative. The prediction of burst pressures for external longitudinal semielliptical part-through cracks in X70 steel pipe showed that the magnitudes of predicted burst pressures came very close to each other, and were conservative compared to FEM (finite element method) calculations and experimentally determined burst pressures.

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J-integral evaluation of a mode I crack in gradient nanocrystalline metals

Cited by 4 publications

References 44 publications

Improved back propagation neural network based on the enrichment for the crack propagation

Improved back propagation neural network based on the enrichment for the crack propagation

Evaluating the J-integral of mode I crack in gradient nanocrystalline metals with residual stress induced by surface mechanical treatment

Comparison of J Integral Assessments for Cracked Plates and Pipes

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