GLTRS--Glenn
TITLE AND SUBTITLE:
A Differential CDM Model for Fatigue of Unidirectional Metal Matrix Composites

AUTHOR(S):
S.M. Arnold and S. Kruch

REPORT DATE:
November 1992

FUNDING NUMBERS:
WU-510-01-50

PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES):
National Aeronautics and Space Administration
Lewis Research Center
Cleveland, Ohio 44135-3191

PERFORMING ORGANIZATION REPORT NUMBER:
E-7128

SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES):
National Aeronautics and Space Administration
Washington, D.C. 20546-0001

REPORT TYPE AND DATES COVERED:
Technical Memorandum

SPONSORING/MONITORING AGENCY REPORT NUMBER:
NASA TM-105726

SUPPLEMENTARY NOTES:
Prepared for the American Society of Mechanical Engineers, Anaheim, California, November 8-13, 1992.
S.M. Arnold, NASA Lewis Research Center, and S. Kruch, ONERA, 92322 Chatillon, France. Responsible person, S.M. Arnold, (216) 433-3334.

ABSTRACT:
A multiaxial, isothermal, continuum damage mechanics model for fatigue of a unidirectional metal matrix composite volume element is presented. The model is phenomenological, stress based, and assumes a single scalar internal damage variable, the evolution of which is anisotropic. The development of the fatigue damage model,
(i.e., evolutionary law) is based on the definition of an initially transversely isotropic fatigue limit surface, a static fracture surface, and a normalized stress amplitude function. The anisotropy of these surfaces and function, and therefore the model, is defined through physically meaningful invariants reflecting the local stress and material orientation. This transversely isotropic model is shown, when taken to it's isotropic limit, to directly simplify to a previously developed and validated isotropic fatigue continuum damage model. Results of a nondimensional parametric study illustrate (1) the flexibility of the present formulation in attempting to characterize a class of composite materials and (2) the capability of the formulation in predicting anticipated qualitative trends in the fatigue behavior of unidirectional metal matrix composites. Also, specific material parameters representing an initial characterization of the composite system SiC/Ti 15-3 and the matrix material (Ti 15-3) are reported.

SUBJECT TERMS:
Continuum damage; Fatigue; Metal matrix composites; Damage accumulation

PDF NOT AVAILABLE VIA WEB:
Reports not available in PDF can be purchased from the Center for AeroSpace Information at:
http://www.sti.nasa.gov select Order Information


This page contains an Adobe® Acrobat® Reader PDF file. The PDF documents have been created to show thumbnails of each page. If the thumbnails do not display properly, download the file to the hard drive and view through Acrobat® Reader. You can download Acrobat® Reader for free. click

NASA NASA GLTRS--Glenn

A service of the NASA Glenn Research Center Logistics and Technical Information Division

Suggestions or questions about this site can be directed to:

NASA official: Technical Publications Manager, Sue.E.Butts@nasa.gov

Web curator: Caroline.A.Rist@grc.nasa.gov

Privacy Policy and Important Notices