0
RESEARCH PAPERS: Gas Turbines: Vehicular

Creep Life of Ceramic Components Using a Finite-Element-Based Integrated Design Program (CARES/CREEP)

[+] Author and Article Information
L. M. Powers

Cleveland State University, Cleveland, OH 44115

O. M. Jadaan

University of Wisconsin—Platteville, Platteville, WI 53818

J. P. Gyekenyesi

NASA-Lewis Research Center, Cleveland, OH 44135

J. Eng. Gas Turbines Power 120(1), 162-171 (Jan 01, 1998) (10 pages) doi:10.1115/1.2818070 History: Received February 01, 1996; Online November 19, 2007

Abstract

The desirable properties of ceramics at high temperatures have generated interest in their use for structural applications such as in advanced turbine systems. Design lives for such systems can exceed 10,000 hours. The long life requirement necessitates subjecting the components to relatively low stresses. The combination of high temperatures and low stresses typically places failure for monolithic ceramics in the creep regime. The objective of this paper is to present a design methodology for predicting the lifetimes of structural components subjected to creep rupture conditions. This methodology utilizes commercially available finite element packages and takes into of a account the time-varying creep strain distributions (stress relaxation). The creep life of a component is discretized into short time, steps, during which the stress and strain distributions are assumed constant. The damage is calculated for each time step based on a modified Monkman–Grant creep rupture criterion. Failure is assumed to occur when the normalized accumulated damage at any point in the component is greater than or equal to unity. The corresponding time will be the creep rupture life for that component. Examples are chosen to demonstrate the CARES/CREEP (Ceramics Analysis and Reliability Evaluation of Structures/CREEP) integrated design program, which is written for the ANSYS finite element package. Depending on the component size and loading conditions, it was found that in real structures one of two competing failure modes (creep or slow crack growth) will dominate. Applications to benchmark problems and engine components are included.

Copyright © 1998 by The American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In