Torsional Fatigue Life of Power-Plant-Shaft Material. Final Report, Task I

摘要

Research on the torsional fatigue life of power plant rotating shafts is reported. Grips, fixtures, and test specimens and apparatus were developed for materials testing under torsion-only and combined axial-torsion loading. A series of torsional fatigue tests, and also a series of axial fatigue tests, were done on shaft material. Existing Westinghouse computer codes (WECAN) were modified to allow elastic and plastic stress analysis of axisymmetric bodies in torison to be done by finite elements. Elastic analysis for a notched torsional specimen is complete. Extensive background analysis and literature review work was done and is reported in detail. Examination of the local strain approach to life prediction for notched members indicates that this approach is expected to be applicable to torsional loading. Based on existing limited data, straightforward modifications to account for state of stress effects appear to be sufficient. The effects of size and crack growth appear to be closely related, suggesting that current approaches to accounting for size effects need to be reconsidered. (ERA citation 08:029498)