Year

2025

Season

Spring

Paper Type

Master's Thesis

College

College of Computing, Engineering & Construction

Degree Name

Master of Science in Electrical Engineering (MSEE)

Department

Engineering

NACO controlled Corporate Body

University of North Florida. School of Engineering

Committee Chairperson

Dr. William Dally

Second Advisor

Dr. O. Patrick Kreidl

Third Advisor

Dr. Brian Kopp

Fourth Advisor

Dr. Alan Harris

Abstract

A strain gage-based instrumentation system was designed and fabricated to measure the moment present at the base of a mock, diesel-engine snorkel for a submerged vehicle designed to operate in the surf zone. Afterwards, a lab experiment was designed and executed to determine the accuracy of the instrument and a 2-dimensional, matrix-vector equation was formulated to relate pairs of voltages, Vx and Vy, to moments, Mx and My for the experiment. Three versions of this model were built. The first model was created using traditional statics equations governing strain, stress, moment, force. The second and third models were built directly from linear regression methods applied to the input and output data from the laboratory experiments. The second, ”diagonal” model assumed no interdependence between sensors on the predicted moment while the third, ”full” model allowed for interdependence. Each of the three models was then used to estimate the moment at the base of the mock snorkel using voltage measurements from each experiment. The estimates were then compared to the true moment data from each experiment. The error statistics calculated from these estimates revealed significant estimation bias for the theoretical statics model which was not present in the diagonal and full models. The diagonal and full models both had zero mean error, low standard deviation of that error and were slightly negatively correlated. Furthermore, there was only a 7% improvement in the accuracy of the full model over the diagonal model which was interpreted as the sensors having little dependence on each other with respect to the estimated moment. The work done in this thesis will enable the prediction of moments present on the mock snorkel during tow tests through the marine environment when the mock snorkel is equipped with and without freely-rotating, segmented, fairings. If the fairings decrease the drag forces on the mock snorkel they could be implemented on the submerged vehicle that operates in the surf zone to reduce the chance of a catastrophic failure.

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