LOCAL STRESS-STRAIN APPROACH TO CUMULATIVE FATIGUE DAMAGE ANALYSIS

A cumulative fatigue damage procedure for estimating the fatigue crack initiation life of notched structural members subjected to known load histories is outlined. This procedure assumes that a knowledge of the local cyclic stress-strain response of the metal at the most severely strained region in a member is sufficient to predict when a crack will form there. Some of the steps in this procedure that are of current interest and which are especially applicable to a local stress-strain approach are discussed. Alternative, approximate and/or abbreviated steps in the cumulative fatigue damage procedure are given wherever possible. Limitations of the method and areas where research is needed are pointed out. Cumulative fatigue test results for smooth specimens, notched plates and built-up box beams are compared to life calculations made using the local stress-strain approach. Cyclic deformation and fracture properties, used in the analysis, were obtained from tests on a limited number of axially loaded unnotched specimens. These examples indicate that a cumulative fatigue damage analysis based on the local stress-strain approach employing a minimum amount of materials test data can be used to make reasonable life estimates for members similar to many practical structural members. (Modified author abstract)

• Corporate Authors:

  University of Illinois, Urbana-Champaign

  Department of Theoretical and Applied Mechanics
  Urbana, IL  United States  61801
• Authors:
  • Morrow, J D
  • MARTIN, J F
  • DOWLING, N E
• Publication Date: 1974-1

Media Info

• Pagination: 80 p.

Subject/Index Terms

• TRT Terms: Cracking; Fatigue cracking; Fracture mechanics; Notch tests; Repeated loads
• Old TRIS Terms: Cyclic fatigue
• Subject Areas: Marine Transportation; Materials;

Filing Info

• Accession Number: 00057247
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: Final Rpt.
• Contract Numbers: N00156-70-C-1256
• Files: TRIS
• Created Date: Aug 28 1974 12:00AM