Blade root attachment evaluation low-cycle fatigue estimates based on probabilistic approach
- Stress Technology Inc., Rochester, NY (United States)
- Electric Power Research Inst., Palo Alto, CA (United States)
When utilities purchase replacement blades from a manufacturer, the machining tolerances in the root attachment and the material fatigue properties are a major quality concern. These factors can have significant impact on the low-cycle fatigue life. For any replacement blades, the primary concern is to minimize the risk of an in-service failure. However, excessively conservative acceptance criteria would unnecessarily drive up the unit price for the replacement blades. Acceptance criteria with estimates of associated risks of in-service failure are therefore needed for each specific blade design based on the expected operating environment, material, and service life. In the work presented herein, a probabilistic model to estimate LCF in the blade root attachment is presented. The approach is demonstrated using stresses and material fatigue properties for a representative LP last stage blade of a steam turbine. The LCF life estimates obtained using the proposed approach show good correlation with field experience.
- OSTI ID:
- 549982
- Report Number(s):
- CONF-961006--; ISBN 0-7918-1796-2
- Country of Publication:
- United States
- Language:
- English
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