University of Illinois Urbana-Champaign

Factors influencing plane strain crack toughness values of structural steel

Shoemaker, Alan Kent

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https://hdl.handle.net/2142/112022

Description

Title
Factors influencing plane strain crack toughness values of structural steel
Author(s)
Shoemaker, Alan Kent
Issue Date
1967-07
Keyword(s)
  • Strain
  • Crack Toughness
  • Steel
Abstract
The crack toughness behavior of a 3/4 –inch-thick X-52 line-pipe plate, which had a static room temperature yield stress value of 45,000 psi, was examined over the temperature range from -280 F to 0 F for strain rates of 8x10-5/sec, 3x10-3/sec and 1.5/sec. Crack toughness data, which were obtained from notched bend and single edge notched specimens, are presented for precracking conditions with a maximum nominal stress of 25 percent and 50 percent of the room temperature yield stress. The crack toughness data indicated that for each strain rate the region of plane strain KIC values, which had only a small sensitivity to temperature, were followed by an abrupt increase in temperature sensitivity which was interpreted as the start of the transition behavior. A flat brittle-appearing fracture surface did not guarantee a plane strain initiation behavior since shear lips were observed only above a temperature of -70F and the transition for the lowest and intermediate strain rate occurred below this temperature. A reduction in the measured crack toughness values was found when the precracking maximum fatigue level was reduced from 50 percent to 25 percent of the room temperature yield stress. As a criterion for the effect of precracking stress level on the measured crack toughness values, it was concluded that elevated crack toughness values were measured if the plastic zone size during precracking (at room temperature) was larger than that obtained in the KIC test. The use of a rate parameter, T ln A/ϵ, was examined for correlating the effects of temperature and strain rate on plane strain crack toughness values.
Publisher
Department of Theoretical and Applied Mechanics. College of Engineering. University of Illinois at Urbana-Champaign
Series/Report Name or Number
  • TAM R 299
  • 1968-0014
ISSN
0073-5264
Type of Resource
text
Language
eng
Permalink
http://hdl.handle.net/2142/112022
Sponsor(s)/Grant Number(s)
American Iron and Steel Institute, Committee on Properties of Iron and Steel; AISI 44 22 60 302
Copyright and License Information
Copyright 1967 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.