Date on Master's Thesis/Doctoral Dissertation

12-2005

Document Type

Master's Thesis

Degree Name

M.S.

Department

Mechanical Engineering

Committee Chair

Bradshaw, Roger D.

Subject

Materials--Testing; Airplanes--Inspection

Abstract

The airline regulatory communities are interested in methods that can access degradation in the polymer insulation of aging aircraft wiring. This study investigates the response of bulk polymer films and aircraft wiring under indentation; changes in the behavior of the material may provide an indication of degradation. For this study, indentation tests are performed using a dynamic mechanical analyzer (DMA), which provides excellent force and displacement sensitivity and can test materials at a wide range of temperatures. Each indentation test consists of two test phases: loading and relaxation. During loading, the indenter is displaced into the material at a constant rate. During relaxation, the indenter is maintained at the final position of the loading phase for a period of time. The force is monitored throughout the test, increasing during the loading phase and decreasing during the relaxation phase. Pristine and aged specimens were considered to assess the changes occurring in the force response of the material in question. Tests were performed on bulk polymer films and a limited number of wire samples. The findings were as expected, with the wires and the polymer film specimens stiffening with aging. The findings from the study will be used to assist in the ongoing development of methods to assess wire degradation in a field environment.

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