Accession Number:

AD1004972

Title:

The Measurement of Elastic Strain Fields and Line-Broadening Near Cracks in Loaded Bars of HY-80 Steel

Descriptive Note:

Technical Report

Corporate Author:

Defence Research Establishment Atlantic Dartmouth, Nova Scotia Canada

Personal Author(s):

• Holden,T. M.
• Root,J. H.
• Mecke,J. F.

Report Date:

1993-04-30

Pagination or Media Count:

29.0

Abstract:

The elastlc strain fields in the neighbourhood of 6 mm and 20 mm deep cracks in bars loaded in three-point bending were measured by neutron diffraction. Calculations of the elastic strain field under the known loads included a stress-concentration contribution approximated by linear elastic fracturemechanics LEFM. Close to the crack tip, the calculated load-induced strains with the LBFM contribution are in reasonable agreement with the measurements although the agreement is not good far from the crack. The diffraction linewidths can be related to the plastic deformation within the region of measurement. A 20 increase in linewidth occurred ahead of and behind the crack tip, and near the uncracked surface adjacent to the central support for the three-point bending. The radius of the enhanced linewidth region was about 5 mm near the crack tip.

Descriptors:

• STRAIN (MECHANICS)
• measurement
• crack tips
• plastic deformation
• deformation (mechanics)
• steel
• NEUTRON DIFFRACTION
• STRAIN GAGES
• CRACKING (FRACTURING)

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE