Title

An Improved Anisotropic Tertiary Creep Damage Formulation

Keywords

continuum damage mechanics (CDM); directionally solidified; multiaxial; Ni-base superalloy; transversely isotropic; void induced anisotropy

Abstract

Directionally solidified (DS) Ni-base superalloys are commonly used as gas turbine materials to primarily extend the operational lives of components under high load and temperature. The nature of DS superalloy grain structure facilitates an elongated grain orientation, which exhibits enhanced impact strength, high temperature creep and fatigue resistance, and improved corrosion resistance compared with off-axis orientations. Of concern to turbine designers are the effects of cyclic fatigue, thermal gradients, and potential stress concentrations when dealing with orientation-dependent materials. When coupled with a creep environment, accurate prediction of crack initiation and propagation becomes highly dependent on the quality of the constitutive damage model implemented. This paper describes the development of an improved anisotropic tertiary creep damage model implemented in a general-purpose finite element analysis software. The creep damage formulation is a tensorial extension of a variation in the Kachanov-Rabotnov isotropic tertiary creep damage formulation. The net/effective stress arises from the use of the Rabotnov second-rank symmetric damage tensor. The Hill anisotropic behavior analogy is used to model secondary creep and tertiary creep damage behaviors. Using available experimental data for a directionally solidified Ni-base superalloy, the improved formulation is found to accurately model intermediate oriented specimen. © 2011 American Society of Mechanical Engineers.

Publication Date

7-28-2011

Publication Title

Journal of Pressure Vessel Technology, Transactions of the ASME

Volume

133

Issue

5

Number of Pages

-

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1115/1.4002497

Socpus ID

79960660369 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/79960660369

This document is currently not available here.

Share

COinS