Reliability of steam-turbine rotors. Task 1. Lifetime prediction analysis system. Final report. [Using STRAP and SAFER computer codes and boresonic data]
Task 1 of RP 502, Reliability of Steam Turbine Rotors, resulted in the development of a computerized lifetime prediction analysis system (STRAP) for the automatic evaluation of rotor integrity based upon the results of a boresonic examination of near-bore defects. Concurrently an advanced boresonic examination system (TREES), designed to acquire data automatically for lifetime analysis, was developed and delivered to the maintenance shop of a major utility. This system and a semi-automated, state-of-the-art system (BUCS) were evaluated on two retired rotors as part of the Task 2 effort. A modified nonproprietary version of STRAP, called SAFER, is now available for rotor lifetime prediction analysis. STRAP and SAFER share a common fracture analysis postprocessor for rapid evaluation of either conventional boresonic amplitude data or TREES cell data. The final version of this postprocessor contains general stress intensity correlations for elliptical cracks in a radial stress gradient and provision for elastic-plastic instability of the ligament between an imbedded crack and the bore surface. Both linear elastic and ligament rupture models were developed for rapid analysis of linkup within three-dimensional clusters of defects. Bore stress-rupture criteria are included, but a creep-fatigue crack growth data base is not available. Physical and mechanical properties of air-melt 1CrMoV forgings are built into the program; however, only bounding values of fracture toughness versus temperature are available. Owing to the lack of data regarding the probability of flaw detection for the boresonic systems and of quantitative verification of the flaw linkup analysis, automatic evlauation of boresonic results is not recommended, and the lifetime prediction system is currently restricted to conservative, deterministic analysis of specified flaw geometries.
- Research Organization:
- Southwest Research Inst., San Antonio, TX (USA)
- OSTI ID:
- 6588242
- Report Number(s):
- EPRI-NP-2661; ON: DE83901096
- Resource Relation:
- Other Information: Portions are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
42 ENGINEERING
COMPUTER CODES
S CODES
ROTORS
RELIABILITY
SERVICE LIFE
STEAM TURBINES
THERMAL POWER PLANTS
CRACK PROPAGATION
DATA PROCESSING
DEFECTS
FAILURES
FATIGUE
FORECASTING
NONDESTRUCTIVE TESTING
MACHINERY
MATERIALS TESTING
MECHANICAL PROPERTIES
POWER PLANTS
PROCESSING
TESTING
TURBINES
TURBOMACHINERY
200104* - Fossil-Fueled Power Plants- Components
420500 - Engineering- Materials Testing