Crack Closure Characteristics Considering Center Cracked and Compact Tension Specimens.
Abstract
Due to growing use of expensive, high performance gas turbine engines in the United States Air Force, there is no need for improved failure prediction methods for critical high temperature engine components. This thesis expands current research in the area of high temperature, low cycle fatigue of IN-100 at 1350 F. IN-100 is a superplastically forged, nickel-based superalloy used in F-100 engine turbine disks. This thesis describes an in-house 2-D, finite element program named VISCO which employs the Bodner-Partom Constitutive equation to accurately model the principal features of completely reversed cyclic loading. VISCO is used to compare the effects on material behavior by considering a 2.5 Hz compact tension specimen, a .167 Hz compact tension specimen, and a 2.5 Hz center cracked specimen subjected to fully reversed cyclic loading with a stress intensity factor of 35 and 45 ksi/sq in. The comparisons point out that the findings of Linear Elastic Mechanics must be modified under conditions of high temperature viscoplasticity. Originator supplied keywords include: High temperature fatigue; Fracture mechanics; High temperature superalloy; Viscoplasticity; Bodner-Partom flow law; and Finite element modeling.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1984
- Accession Number
- ADA151702
Entities
People
- C. L. Henkel
Organizations
- Air Force Institute of Technology