Year

2020

Season

Fall

Paper Type

Master's Thesis

College

College of Computing, Engineering & Construction

Degree Name

Master of Science in Civil Engineering (MSCE)

Department

Engineering

NACO controlled Corporate Body

University of North Florida. School of Engineering

First Advisor

Raphael Crowley, PhD PE

Second Advisor

Donald Resio, PhD

Rights Statement

http://rightsstatements.org/vocab/InC/1.0/

Third Advisor

Adel ElSafty, PhD, PE

Department Chair

Osama Jadaan, PhD

College Dean

William Klosermeyer, PhD

Abstract

Dynamic loading of marine fenders is a situation that is unique to the United States Navy (USN), due to the use of Heavy Weather Mooring (HWM) for naval vessels during extreme weather events, such as hurricanes. Traditional analysis has not been concerned with the fender reaction on vessel hulls. However, newer classes of Naval ships, such as the Littoral Combat Ships (LCS), have designs that emphasize speed and agility, resulting in them having thinner hulls more susceptible to damage from fenders. In traditional analysis, fenders are modeled as idealized springs, with static- load derived spring constants from manufacturer charts. This has been adequate for previous warships, however with more susceptible warships, a better understanding of the fenders reaction is required.

Two series of tests were created, a quasi-static testing series to mimic the current testing of fenders, and a cyclic testing series to determine if repeated loading of fenders would provoke a dynamic response.

Testing was conducting using a Finite Element Analysis (FEA) model to simulate ship impacts on fenders and determine the fender reaction to both quasi-static and cyclic loading patterns at various ship velocities and loading periods.

This research found that there was no impact on fender response provoked by a difference in loading speed during quasi-static testing. Cyclic loading of the fender did not provoke a dynamic fender response even under a second wave cycle where impact forcing could have caused different behavior. Overall, results of this study lead to the conclusions that both loading speed and loading pattern do not have an impact on fender response.

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