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%0 Thesis
%A Dölz, Michael
%T Mikrostruktursensitive Modellierung der wasserstoffinduzierten Rissbildung von Rohrleitungsstählen
%I Rheinisch-Westfälische Technische Hochschule Aachen
%V Dissertation
%C Aachen
%M RWTH-2021-00219
%P 1 Online-Ressource (XIV, 124 Seiten) : Illustrationen, Diagramme
%D 2020
%Z Veröffentlicht auf dem Publikationsserver der RWTH Aachen University 2021
%Z Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2020
%X In the present work, the microstructural influence on hydrogen-induced cracking is described using a three-dimensional numerical modelling approach with the commercial software ABAQUS FEA. The two-dimensional model according to Oriani and Barrera, which previously has been published in literature, was replicated, validated with an analytical solution and extended to the three-dimensional application. The resulting problem of meshing complex geometries with hexahedral elements could be counteracted by the use of tetrahedral elements. The mathematical deviation between the local hydrogen concentration of the analytically validated hexahedral elements and the tetrahedral elements was solved by a developed linear element compensation function. Furthermore, the HEDE and HELP mechanisms were implemented in the form of a concentration-dependent stress or strain-controlled damage criterion. On the basis of real permeation tests, the newly developed three-dimensional material model could successfully generate virtual permeation measurements hence enable the derivation of the effective diffusion coefficient of the investigated low alloy pipeline steel. The investigations of inclusion-affected representative submodels with different fictional as well as real inclusion characteristics showed that a strong correlation between the development of the local hydrogen concentration and the existing inclusion chemistry can be observed. Additionally, the influence of size and shape of the inclusions could be shown. The model for the description of the stress-dependent hydrogen diffusion was applied to determine the critical non-metallic inclusions. The comparison of different inclusion systems showed that inclusions with the chemical composition Al2O3 in particular led to a significant increase in the local hydrogen concentration. Thus, proving that especially these inclusions contribute critically to the hydrogen-induced crack initiation.
%F PUB:(DE-HGF)11
%9 Dissertation / PhD Thesis
%R 10.18154/RWTH-2021-00219
%U https://publications.rwth-aachen.de/record/809895