Date of Award:

5-2010

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Mechanical and Aerospace Engineering

Advisor/Chair:

Thomas H. Fronk

Abstract

Certain 30mm munitions used in various military applications are configured with a glass-reinforced nylon band that acts as a firing ring or rotating band. The purpose of this research is to investigate whether storage environments compromise the strength and integrity of the glass-reinforced nylon rotating bands by researching the environmental factors that will degrade nylon and by performing tests to investigate if these factors will embrittle nylon composites. Moisture and temperature are found to be the environmental factors that will have an effect on the rotating bands in their respective storage environments. Absorbed moisture is found to increase the impact strength of nylon while at the same time expanding surface defects and attacking fiber/matrix bonds.

Two impact tests using a Tinius Olsen impact tester are used to determine the effects of different storage environments on the impact strength of neat resin nylon 6/12 and 33% glass-reinforced nylon 6/12. The relative Shore D hardness of each reinforced sample is also measured to determine if any correlation between impact strength and hardness exists. Absorbed moisture is found to increase the toughness of both neat resin and reinforced nylon samples, but once dried again no significant difference in impact strength is found.

A third test using a horizontal milling machine and a specially shaped tool is run to try and recreate the deformation that the rotating band sees when impacting the rifling of the gun. This test proved to be unsuccessful in generating brittle failure in glass-reinforced test samples.

Comments

This work made publicly available electronically on August 2, 2010.

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