Karl A. Hart

Date of Award

12-1992

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Aeronautics and Astronautics

First Advisor

Shankar Mall, PhD

Abstract

This study investigated the behavior of the SCS6/Ti-15-3 metal matrix composite with a quasi-isotropic layup when tested under static and fatigue conditions. Specimens were subjected to in-phase and out-of-phase thermo- mechanical and isothermal fatigue loading. In-phase and isothermal loading produced a fiber dominated failure while the out-of-phase loading produced a matrix dominated failure. Also, fiber domination in all three profiles was present at higher maximum applied loads and al three profiles demonstrated matrix domination at lower maximum applied loads. Thus, failure is both profile dependent and load equipment. Additional analyses, using laminated plate theory, Halpin-Tsai equations, METCAN, and the Linear Life Fraction Model (LLFM), showed: the 'as-received' specimens contained plies where a portion of the fibers are debonded from the matrix; during fatigue cycling, the 90° plies and a percentage of the 45° plies failed immediately with greater damage becoming evident with additional cycles; and, the LLFM suggests that there may be a non-linear combination of fiber and matrix domination for in-phase and isothermal cycling.

AFIT Designator

AFIT-GAE-ENY-92D-05

DTIC Accession Number

ADA258902

Comments

The author's Vita page is omitted.

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