Date of Award


Document Type


Degree Name

Master of Science in Aeronautical Engineering


Department of Aeronautics and Astronautics

First Advisor

Shankar Mall, PhD


This stuidy investigates the fatigue response of a cross-ply [0/90]2s Nicalon/Calcium Aluminosillicate (Nicalcc/CAS) ceramic matrix composite at room temperature under strain controlled tension-tension and tension-compression fatigue loading. The primary objectives were to determine strain fatigue limits for both loading cases and to complete a fatigue life diagram (Δe-N) for all tests. Failure mechanisms were also studied. The average initial modulus value for this lay-up was 120 GPa. The ultimate tensile strain was 0.00988 mn/mm (285 MPa). Eight tests were conducted with maximum strains that ranged from 0.00300 mm/mm to 0.00722 mm/mm. The tension-tension fatigue limit was found to be Δe=0.00270 mm/mm. There was no evidence of random fiber failure. Five tension-compression tests were performed at maximum strains that ranged from 0.00135 mm/mm to 0.00325 mm/mm. The fatigue limit for this set of tests was found to be the same as that fatigue limit for the tension-tension tests, Δe=0.00270 mm/mm. Longitudinal cracks formed in all the specimens and were the major cause of failure. The fatigue life diagram for these tests coincided with the tension-tension tests until at the higher strains where the failure mode changed from tensile failure to compressive failure.

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DTIC Accession Number



The author's Vita page is omitted.