Accession Number:

ADA279130

Title:

Influence of Fatigue Crack Closure on the Growth Rate of Surface Flaws

Descriptive Note:

Final rept. Sep 1982-May 1988

Corporate Author:

WRIGHT LAB WRIGHT-PATTERSON AFB OH

Personal Author(s):

Report Date:

1994-02-01

Pagination or Media Count:

239.0

Abstract:

Inconsistent experimental results of fatigue crack closure studies over the past 15 years have caused recent investigators to conclude that the fundamental phenomena controlling the crack driving mechanisms are not understood. A major contributor to this misunderstanding is an inadequate understanding of the complex three-dimensional nature of closure. This is true for two-dimensional thru-the-thickness cracks as well as for three-dimensional part-thru surface cracks. To assess the three-dimensional influences of fatigue crack closure on the growth rate of surface flaws, an experimental investigation was conducted using a rectangular plate of polymethylmethacrylate PMMA material loaded in four-point bending. The use of transparent PMMA material and a Newton optical interferometer system with a laser light source provided the capability to simultaneously measure three-dimensional crack opening displacement COD profiles and closure loads Pc1.

Subject Categories:

  • Plastics
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE