The available analytical models for predicting the fatigue behavior of weldments under variable amplitude load histories were compared using test results for weldments subjected to the SAE bracket and transmission variable load amplitude histories. Models based on detail S-N diagrams, such as the Munse Fatigue Design Procedure (MFDP), were found to perform well except when the history had a significant average mean stress. Models based on fatigue crack propagation alone were generally conservative, while a model based upon estmates of both fatigue crack initiation and propagation (the I-P Model) performed the best. An extensive series of fatigue tests was carried out on welded structural details commonly encountered in ship construction, using a variable load history that simulated the service history of a ship. The results showed that linear cumulative damage concepts predicted the test results, but the importance of small stress range events was not studied because events smaller than 68 MPa (10 ksi) stress range were deleted from the developed ship history to reduce the time required for testing. An appreciable effect of mean stress was observed, but the results did not verify the existence of a specimen-size effect. Baseline constant-amplitude S-N diagrams were developed for five complex ship details not commonly studied in the past.

  • Supplemental Notes:
    • Report; A Ship Structure Committee Report
  • Corporate Authors:

    University of Illinois, Urbana-Champaign

    Department of Civil and Environmental Engineering
    205 North Mathews Avenue
    Urbana, IL  United States  61801-2352

    United States Coast Guard

    2100 Second Street, SW
    Washington, DC  United States  20593
  • Authors:
    • PARK, S K
    • Lawrence, F V
  • Publication Date: 1990-12

Media Info

  • Features: References;
  • Pagination: 213 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00661805
  • Record Type: Publication
  • Source Agency: Maritime Technical Information Facility
  • Report/Paper Numbers: SSC-346
  • Contract Numbers: DTCG-23-84-C-20018
  • Files: TRIS
  • Created Date: Jul 21 1994 12:00AM