ANALYSIS OF FATIGUE CRACK PROPAGATION

THE CORRELATION BETWEEN FATIGUE CRACK PROPAGATION AND STRESS INTENSITY FACTOR IS ANALYZED. WHEN ONE MEASURES FATIGUE CRACK PROPAGATION RATE, A CRACK INCREMENT "DELTA A", AND ITS CORRESPONDING INCREMENT IN LOAD CYCLES, "DELTA N" ARE MEASURED. FATIGUE CRACK PROPAGATION MUST BE CAUSED BY A SHEAR AND/OR A NORMAL SEPARATION MODE. BOTH OF THESE TWO PROCESSES ARE DISCRETE IF ONE LOOKS AT THE ATOMIC LEVEL. IF THE "AVERAGE" DEFORMATION AND FRACTURE PROPERTEIS OVER THE CRACK INCREMENTS "DELTA A", CAN BE CONSIDERED AS HOMOGENEOUS, IF THE CHARACTERISTIC DISCRETE LENGTHS OF THESE DEFORMATION AND FRACTURE PROCESSES ARE MUCH SMALLER THAN THE CRACK INCREMENT PER CYCLE, IF THE PLASTIC ZONE SIZE IS SMALL, AND IF A PLATE IS THICK ENOUGH TO INSURE A PLANE STRAIN CASE, DA/DN IS PROPORTIONAL TO "DELTA K SQUARE". ANY DEVIATION OF EMPIRICAL DATA FROM THIS RELATION MUST BE CAUSED BY THE FACT THAT ONE OR MORE OF THESE CONDITIONS ARE NOT SATISFIED. THE EFFECTS OF PLATE THICKNESS AND MATERIAL INHOMOGENEITY ARE DISCUSSED IN DETAIL. A SHEAR SEPARATION MODE OF FATIGUE CRACK PROPAGATION IS DESCRIBED AND IS USED TO ILLUSTRATE THE EFFECTS OF MATERIAL INHOMOGENEITY. /AUTHOR/

  • Availability:
  • Supplemental Notes:
    • Rept No MTS-HWL-0472APPS
  • Corporate Authors:

    Syracuse University

    Syracuse University Administration Building
    Syracuse, NY  United States  13210
  • Authors:
    • Liu, Han-Wen
  • Publication Date: 1972-4

Media Info

  • Features: Figures; References;
  • Pagination: 21 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00210049
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Mar 15 1974 12:00AM