Date of Award

1-1-2011

Document Type

Campus Access Thesis

Department

Mechanical Engineering

First Advisor

Jeff Morehouse

Second Advisor

William Ranson

Abstract

As infrastructure and aircraft age, there is a need to monitor critical areas on these structures to detect the aging and prevent failure. Structural health monitoring (SHM) has become a key area to detect the aging in aerospace and infrastructure industry, monitoring these structures actively or passively using non-destructive testing (NDT) and non-destructive inspection (NDI) techniques. NDI crack detection and strain measurement systems are currently used in critical areas of structures, but are limited due to needing wires for communication and a power source. Although these SHM technologies continue to develop, becoming more and more precise, a lighter wireless device is sought which eliminates the weight and complexity associated with a network of wires.

The objective of this thesis was to develop a self powered experimental device which measures strain as well as detecting and monitoring cracks, and transmits the data wirelessly. This SHM device was subjected to two test scenarios: static loading and fatigue loading. The static loading test directly compared the Direct Measurements, Inc (DMI) DSE gage with a traditional electrical resistance strain gage, in order to validate the strain measurements taken by the DSE gage. The fatigue test involved propagating a crack beneath the DSE gage in order for the gage to detect and monitor crack intensity as it grew across a specimen. Both tests utilized the wireless battery-powered capabilities of the device. Overall, the DSE sensor is capable of measuring strain accurately when compared to electrical resistance strain gage. However, this sensor's true purpose lies in its ability to detect and monitor cracks, as was demonstrated in the fatigue crack test.

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