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

Centrally notched (hole), cross-ply, ((0/90)2)s, and unidirectional, (0)8 laminates of Silicon Carbide fiber-reinforced Aluminosilicate glass, SiC/1723, were fatigue tested under tension-compression loading with a load ratio of -1. Damage accumulated continuously for both lay- ups, leading to eventual failure and a reduced fatigue life. Critical damage in the cross-ply consisted of longitudinal cracks in the 90° plies growing and combining with transverse cracks to effectively eliminate the 90° plies' load carrying capability and allowing the specimen to buckle. Critical damage in the unidirectional lay-up consisted of longitudinal cracks which initiated at the shear stress concentration points on the hole periphery. Reversed cyclic loading caused continued crack growth at maximum stresses below the tension-tension fatigue limit. The cross-ply lay-up appeared insensitive to the hole, while critical damage in the unidirectional lay-up was dependent on the shear stress concentrations at the hole.

AFIT Designator

AFIT-GAE-ENY-92D-26

DTIC Accession Number

ADA258907

Comments

The author's Vita page is omitted.

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