University of Illinois Urbana-Champaign

Relationship between tensile properties and microscopically ductile plane strain fracture toughness

Sailors, R. H.

Permalink

https://hdl.handle.net/2142/112096

Description

Title
Relationship between tensile properties and microscopically ductile plane strain fracture toughness
Author(s)
Sailors, R. H.
Issue Date
1973
Keyword(s)
  • Tensile Properties
  • Strain
  • Fracture Toughness
Abstract
An attempt has been made to derive an expression that will permit plane strain fracture toughness, KIC, to be calculated from a knowledge of uniaxial tensile properties. Extensive analytical analyses of near crack tip behavior had been performed for plane stress rigid plastic material behavior but not for plane strain work hardening material behavior. Thus, the results of the plane stress rigid plastic behavior were corrected for constraint and strain hardening and found to accurately describe experimental crack opening displacement, δ, on steels having yield strengths from 36 to 161 ksi. The crack opening displacement imposed strain distribution at fracture was investigated by measuring fracture ductility for the biaxial stress state, which exists at the blunted crack tip, and the triaxial stress state, which exists ahead of the crack tip. The results of ductility tests appear to be compatible with a 1/r strain distribution within a region 2δ ahead of the crack tip. Plane strain fracture toughness was measured in three low alloy steels, whose yield strength ranged from 41 to 161 ksi, by the recent J-integral technique. From tests on specimens having various crack lengths, a relative size requirement for plane strain behavior, thickness/uncracked ligament greater than two, was determined. The plane strain value of J, JIC, was checked against, and found to agree with, GIC determined by linear elastic fracture mechanics for two of the three steels investigated. The crack tip was modeled following a recent slip line field characterization of near tip deformation. From the results of plane strain crack opening displacement, crack tip strain distribution, and known fracture toughness values, a length parameter was identified which was shown to be proportional to mean free ferrite path. For the steels investigated, the following expression accurately described fracture toughness, KIC.
Publisher
Department of Theoretical and Applied Mechanics. College of Engineering. University of Illinois at Urbana-Champaign
Series/Report Name or Number
  • TAM R 367
  • 1973-6002
ISSN
0073-5264
Type of Resource
text
Language
eng
Permalink
http://hdl.handle.net/2142/112096
Sponsor(s)/Grant Number(s)
Caterpillar Tractor Company, Peoria, IL, 73/
Copyright and License Information
Copyright 1973 Board of Trustees of the University of Illinois

Owning Collections

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.