Application of two creep fatigue life models for the prediction of elevated temperature crack initiation of a nickel base alloy

Moreno, V.; Nissley, David M.; Halford, Gary R.; Saltsman, J. F.

doi:10.2514/6.1985-1420

Cited by 2 publications

(1 citation statement)

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“…Here, the TS-SRP method was applied by Moreno et al (1985) Predictionof thesetest results shouldimprove when ]149°C(2100°F) isothermal tests are included in the dataset usedto determine model constants. Additionalmodel modification will benecessary to includethe effect of biaxial coatingloadsintroduced by the thermal growth mismatch between the coating andthe substrateduringuniaxia]TMF tests and engine transients.…”

Section: Introductionmentioning

confidence: 99%

Fatigue Life Prediction Modeling for Turbine Hot Section Materials

Halford

Meyer

Nelson

et al. 1989

Journal of Engineering for Gas Turbines and Power

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This paper presents a summary of the life prediction methods developed under the NASA Lewis Research Center’s Hot Section Technology (HOST) program. A major objective of the fatigue and fracture efforts under the HOST program was to significantly improve the analytic life prediction tools used by the aeronautical gas turbine engine industry. This has been achieved in the areas of high-temperature thermal and mechanical fatigue of bare and coated high-temperature superalloys. Such technical improvements will eventually reduce life cycle costs. The cyclic crack initiation and propagation resistance of nominally isotropic polycrystalline alloys and highly anisotropic single crystal alloys have been addressed. A sizeable data base has been generated for three alloys [cast PWA 1455 (B–1900 + Hf), wrought Inconel 718, and cast single-crystal PWA 1480] in bare and coated conditions. Two coating systems, diffusion aluminide (PWA 273) and plasma-sprayed MCrAlY overlay (PWA 286), were employed. Life prediction modeling efforts were devoted to creep-fatigue interaction, oxidation, coatings interactions, multiaxially of stress-strain states, mean stress effects, cumulative damage, and thermomechanical fatigue. The fatigue crack initiation life models developed to date include the Cyclic Damage Accumulation (CDA) Model of Pratt & Whitney and the Total Strain Version of Strainrange Partitioning (TS-SRP) of NASA Lewis for nominally isotropic materials, and the Tensile Hysteretic Energy Model of Pratt & Whitney for anisotropic superalloys. The fatigue model being developed by the General Electric Company is based upon the concepts of Path-Independent Integrals (PII) for describing cyclic crack growth under complex non-linear response at the crack tip due to thermomechanical loading conditions. A micromechanistic oxidation crack extension model has been derived by researchers at Syracuse University. The models are described and discussed in the paper. Only limited verification has been achieved to date as several of the technical programs are still in progress and the verification tasks are scheduled, quite naturally, near the conclusion of the program. To date, efforts have concentrated on developement of independent models for cyclic constitutive behavior, cyclic crack initiation, and cyclic crack propagation. The transition between crack initiation and crack propagation has not been thoroughly researched as yet, and the integration of these models into a unified life prediction method has not been addressed.

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Section: Introductionmentioning

confidence: 99%

Fatigue Life Prediction Modeling for Turbine Hot Section Materials

Halford

Meyer

Nelson

et al. 1989

Journal of Engineering for Gas Turbines and Power

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Critique of Predictive Methods for Treatment of Time-Dependent Metal Fatigue at High Temperatures

2009

Fatigue and Durability of Metals at High Temperatures

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This chapter provides a detailed review of creep-fatigue analysis techniques, including the 10% rule, strain-range partitioning, several variants of the frequency-modified life equation, damage assessment based on tensile hysteresis energy, the OCTF (oxidation, creep, and thermomechanical fatigue) damage model, and numerous methods that make use of creep-rupture, crack-growth, and void-growth data. It also discusses the use of continuum damage mechanics and includes examples demonstrating the accuracy of each method as well as the procedures involved.

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Application of two creep fatigue life models for the prediction of elevated temperature crack initiation of a nickel base alloy

Cited by 2 publications

References 0 publications

Fatigue Life Prediction Modeling for Turbine Hot Section Materials

Fatigue Life Prediction Modeling for Turbine Hot Section Materials

Critique of Predictive Methods for Treatment of Time-Dependent Metal Fatigue at High Temperatures

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