High Temperature Viscoplastic and Creep Crack Growth Behavior of In-100.
Abstract
IN-100, a nickel based powdered alloy, is presently used in turbine disks within the F-100 turbofan engine. It has been found that time dependent inelastic strains can be developed within this material at the high temperature environment of the turbine engine. Therefore, it has been proposed that a much simplified version of a strain-rate sensitive model be employed to capture viscoplastic action. Hence, this thesis involves the study of various mathematical forms of the Malvern overstress constitutive equation. Each of these models employed a finite element computer program to predict crack growth. The computer program incorporates the constant strain triangles. The residual force method was utilized to handle variations in material stiffness due to plastic deformations and creep. In addition, a Hybrid Experimental-Numerical (HEN) procedure was used to trace crack opening displacements near the crack tip. The various mathematical representations of the Malvern model were compared to the Bodner-Partom response. Comparisons were made utilizing total plastic work generated, crack growth rates, and effective stress contours and stress profiles.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1981
- Accession Number
- ADA111094
Entities
People
- Michael H. Bohun
Organizations
- Air Force Institute of Technology