Fatigue Characterization of Fabricated Ship Details. Phase 2
Abstract
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 estimates of both fatigue crack initiation and propagation (the I-P Model) performed the best. An extensive series of fatigue test was carried out on welded structural details commonly encountered in ship construction using a variable load history which simulated the service history of a ship. The results from this study 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.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1988
- Accession Number
- ADA231530
Entities
People
- F. V. Lawrence
- S. K. Park
Organizations
- University of Illinois Urbana–Champaign