Accession Number:

ADA073835

Title:

Crack Tip Plasticity Associated with Corrosion Assisted Fatigue.

Descriptive Note:

Interim rept. Jun 78-Jun 79,

Corporate Author:

SOUTHWEST RESEARCH INST SAN ANTONIO TEX

Personal Author(s):

Report Date:

1979-05-31

Pagination or Media Count:

36.0

Abstract:

A newly developed technique for measuring in-plane crack tip displacements and strains has been applied to the ongoing study of the effect of a water vapor environment on fatigue crack propagation in low-carbon steel. This stereoimaging technique allows the determination of the in-plane displacements with both high resolution and accuracy at numerous points in the near crack tip region. From these displacements the in-plane elements of the strain tensor and the principal strains and shear strains may be calculated. The principal effect of a water vapor environment on crack tip plasticity is that it causes a decrease in strain magnitude which the material at the crack tip supports, corroborating previous results derived from the measurement of subgrain size distribution. Information on the effect of environment on crack opening loads and on the compressive displacements at the tip of the unloaded crack are also given, as are some preliminary results on the interrelationships between loading frequency, environment and crack propagation rate. Author

Subject Categories:

  • Properties of Metals and Alloys
  • Test Facilities, Equipment and Methods
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE