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Catalogue of the numerical solutions for SEN(B) specimen assuming the large strain formulation and plane strain condition

Graba M.

Archives of Civil and Mechanical Engineering

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2012

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Vol. 12, no. 1

29--40

EN

In this paper the values of the maximum opening stress and its distance from crack tip determined for various elastic–plastic materials for single edge notched specimens in bending (SEN(B)) are presented. The influence of the yield strength, the work-hardening exponent and the crack length on the maximum opening stress was tested. The numerical results were approximated by the closed form formulas. In this paper some comments and suggestions about modeling FEM assuming large strain formulation are given.

2

The key problems of local approach to cleavage fracture

Kotrechnko S.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

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2011

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z. 99

30-32

EN

The local approach (LA) to fracture has been considerably developed over the past two decades, not only to provide a better understanding of the frac- ture behavior of materials, in particular the failure micromechanisms, but also to deal with loading conditions which cannot easily be handled with the conventional global fracture mechanics. However, recent findings have demonstrated limitation of both the predictive capabilities and fundamental assumptions of conventional versions of LA to fracture. The main reason of the problems lies in empirical nature of existing versions of LA to cleavage fracture because all of them are based on empirical Weibull distribution which was obtained for very brittle materials, such as ceramics, so, it can’t account for specific features of cleavage fracture of metal. This appears, specifically, in the fact that Weibull distribution parameters, aren’t material’s constants but depend on the temperature, notch radius and plastic strain value.

3

Influence of MESH morphology near the notch on precision of SCF determination

Cichański A.

Journal of Polish CIMAC

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2010

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Vol. 5, no 2

55-63

EN

The researches considered the problem of mesh forming for numerical analyses of notched elements. Stress concentration factor Kt was assumed as the characteristic value determined during the calculations. The calculations were performed for flat bars with opposite U-shaped notches and for round bars with V-shaped notches. Both analysed the notchs generally assumed as shallow notch Kt.1.7 and sharp notch Kt.2.8. Two-dimensional FEM linear elastic analyses were performed in the ANSYS software environment. For the purpose of the analyses, free and mapped meshes for coarse geometry and mapped meshes for modified geometry with one and two subareas were assumed. It has been revealed that precision of numerical calculations for stress concentration factor depends on morpholology of the mesh located near the notch. It has been revealed that free mesh enables to obtain a satisfying precision of the calculations. Introduction of division in formed geometry of the notch for sub-areas followed by their division according to the standard did not improve precision.

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Local approach contributions into the global view of the mechanical crack-tip environment formulation

Katz Y., Tymiak N., Gerberich W. W.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 24, nr 1

162-165

EN

Purpose: Physically based understanding, associate fracture processes to local origins. Even so, in elastic-plastic solids the continuum analysis is mainly engaged with the macroscopic scale. Beside global views the current study emphasise the coupled aspects that are determined by local and material-based factors. Design/methodology/approach: Theoretical/experimental interfaces were adopted mainly cantered on interaction problems. Load interaction in static or dynamic loading and deformation/environment interactions were selected. For the load interaction cases, construction materials were investigated. A metastable stainless steel and hydrogen represented the environment interaction case. Experimentally, novel techniques have been utilized mainly on the nano scale including contact methodology and probe microscope visualization. Findings: The macroscopic background that was supplemented by local findings enabled to refine viable models in quantitative terms. Research limitations/implications: The nano mechanical approach allows additional options to be taken in terms of critical experiments or in order to improve multi-scale models. Originality/value: The nowadays contribution by small volume activities as related to complicated technological topics are highly promising. These avenues are only in early stages, with increasing incentives to advance capabilities assisting applications in nano technology.