ESTIMATING THE FATIGUE CRACK INITIATION LIFE OF WELDS

The fatigue crack initiation life (cycles to obtain a 0.25 mm fatigue crack) was estimated for butt welds using strain-controlled fatigue concepts. Key developments which facilitated these estimates were the assumption of (Kf)max conditions (the largest value of Kf possible for a given weld shape), the use of computer simulation methods which modeled cyclic hardening and softening as well as mean stress relaxation effects, and the use of the fatigue properties of the actual weld zone in which the initial notch was located. The initiation life was found to be very sensitive to changes in Kf, but rather insensitive to strength level. The importance of residual stresses and mean stress varied with material as did the fraction of total life devoted to crack initiation. Mild steel (ASTM A-36) high strength, low alloy (ASTM A-514) steel and aluminum alloy welds were considered.

• Supplemental Notes:
  • Prepared for presentation at ASTM Symposium on Fatigue Testing of Weldments, May 2-3, 1977, in Toronto, Canada.
• Corporate Authors:

  University of Illinois, Urbana-Champaign

  Department of Civil and Environmental Engineering
  205 North Mathews Avenue
  Urbana, IL  United States  61801-2352
• Authors:
  • Lawrence, F V
  • Mattos, R J
  • Higashida, Y
  • Burk, J D
• Publication Date: 1977

Media Info

• Features: References;
• Pagination: 37 p.

Subject/Index Terms

• TRT Terms: Cracking; Defects; Fatigue cracking; Structural analysis; Welds
• Uncontrolled Terms: Crack propagation; Weld defects
• Subject Areas: Marine Transportation; Materials;

Filing Info

• Accession Number: 00159531
• Record Type: Publication
• Source Agency: University of Illinois, Urbana-Champaign
• Files: TRIS
• Created Date: Sep 20 1977 12:00AM