University of Illinois Urbana-Champaign

Enhanced hydrogen concentrations ahead of rounded notches and cracks competition between plastic strain and hydrostatic constraint

Lufrano, Jon M.; Sofronis, Petros

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https://hdl.handle.net/2142/112531

Description

Title
Enhanced hydrogen concentrations ahead of rounded notches and cracks competition between plastic strain and hydrostatic constraint
Author(s)
  • Lufrano, Jon M.
  • Sofronis, Petros
Issue Date
1996-07
Keyword(s)
  • Hydrogen Concentrations
  • Plastic Strain
  • Hydrostatic Constraint
Abstract
The finite element method was used to solve the coupled elastic-plas tic boundary value problem and transient hydrogen diffusion initial boundary value problem. Solutions were obtained at room temperature and under plane strain deformation in the neighborhood of a blunting crack tip under small scale yielding conditions and in the neighborhood of a rounded notch in a 4-point bend specimen. The hydrogen population profiles in both normal interstitial lattice sites (NILS) and trapping sites were calculated and conditions for the predominance of the total amount of hydrogen by either of the populations were studied. It is demonstrated that these conditions depend strongly on initial hydrogen concentration, yield strength, and amount of plastic straining. A discussion of the finite element results in conjunction with different mechanisms of hydrogen embrittlement is presented. If a critical amount of hydrogen is required for hydrogen induced crack initiation, the present results predict locations of crack initiation sites at steel bend specimens which are in agreement with experimental observations on the occurrence of the first microcracking event.
Publisher
Department of Theoretical and Applied Mechanics. College of Engineering. University of Illinois at Urbana-Champaign
Series/Report Name or Number
  • TAM R 830
  • 1996-6017
ISSN
0073-5264
Type of Resource
text
Language
eng
Permalink
http://hdl.handle.net/2142/112531
Sponsor(s)/Grant Number(s)
Energy Department 96/07 DEFG 02 91 ER 45439 96/07
Copyright and License Information
Copyright 1996 Board of Trustees of the University of Illinois

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Technical Reports - Theoretical and Applied Mechanics (TAM) PRIMARY
TAM technical reports include manuscripts intended for publication, theses judged to have general interest, notes prepared for short courses, symposia compiled from outstanding undergraduate projects, and reports prepared for research-sponsoring agencies.