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Record 1 of 21538
Effect of Crystal Orientation on Fatigue Failure of Single Crystal Nickel Base Turbine Blade Superalloys
External Online Source: doi:10.1115/1.1413767
Author and Affiliation:
Arakere, N. K.(Florida Univ., Dept. of Mechanical Engineering, Gainesville, FL, United States)
Swanson, G.(NASA Marshall Space Flight Center, Huntsville, AL, United States)
Abstract: High cycle fatigue (HCF) induced failures in aircraft gas turbine and rocket engine turbopump blades is a pervasive problem. Single crystal nickel turbine blades are being utilized in rocket engine turbopumps and jet engines throughout industry because of their superior creep, stress rupture, melt resistance, and thermomechanical fatigue capabilities over polycrystalline alloys. Currently the most widely used single crystal turbine blade superalloys are PWA 1480/1493, PWA 1484, RENE' N-5 and CMSX-4. These alloys play an important role in commercial, military and space propulsion systems. Single crystal materials have highly orthotropic properties making the position of the crystal lattice relative to the part geometry a significant factor in the overall analysis. The failure modes of single crystal turbine blades are complicated to predict due to the material orthotropy and variations in crystal orientations. Fatigue life estimation of single crystal turbine blades represents an important aspect of durability assessment. It is therefore of practical interest to develop effective fatigue failure criteria for single crystal nickel alloys and to investigate the effects of variation of primary and secondary crystal orientation on fatigue life. A fatigue failure criterion based on the maximum shear stress amplitude /Delta(sub tau)(sub max))] on the 24 octahedral and 6 cube slip systems, is presented for single crystal nickel superalloys (FCC crystal). This criterion reduces the scatter in uniaxial LCF test data considerably for PWA 1493 at 1200 F in air. Additionally, single crystal turbine blades used in the alternate advanced high-pressure fuel turbopump (AHPFTP/AT) are modeled using a large-scale three-dimensional finite element model. This finite element model is capable of accounting for material orthotrophy and variation in primary and secondary crystal orientation. Effects of variation in crystal orientation on blade stress response are studied based on 297 finite element model runs. Fatigue lives at critical points in the blade are computed using finite element stress results and the failure criterion developed. Stress analysis results in the blade attachment region are also presented. Results presented demonstrates that control of secondary and primary crystallographic orientation has the potential to significantly increase a component S resistance to fatigue crack growth with- out adding additional weight or cost. [DOI: 10.1115/1.1413767]
Publication Date: Jan 01, 2002
Document ID:
20040001726
(Acquired Jan 13, 2004)
Subject Category: MECHANICAL ENGINEERING
Report/Patent Number: Paper-00-GT-334
Document Type: Journal Article
Publication Information: Journal of Engineering for Gas Turbines and Power; p. 161-176; Volume 124
Meeting Information: International Gas Turbine and Aeroengine Congress and Exhibition; 8-11 May 2000; Munich; Germany
Meeting Sponsor: American Society of Mechanical Engineers; Washington, DC, United States
Financial Sponsor: NASA Marshall Space Flight Center; Huntsville, AL, United States
Organization Source: NASA Marshall Space Flight Center; Huntsville, AL, United States
Description: 16p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: CRYSTALLOGRAPHY; FATIGUE (MATERIALS); FAILURE MODES; SINGLE CRYSTALS; NICKEL ALLOYS; TURBINE BLADES; THERMODYNAMICS; TURBINE PUMPS; STRESS ANALYSIS; PROPULSION SYSTEM CONFIGURATIONS; PROPULSION SYSTEM PERFORMANCE; HEAT RESISTANT ALLOYS
Availability Source: Other Sources
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