Date of Completion

4-29-2015

Embargo Period

4-28-2015

Keywords

structural dynamics, vibration control, structural acoustics, real-time hybrid testing

Major Advisor

Richard E. Christenson

Associate Advisor

Michael L. Accorsi

Associate Advisor

Jiong Tang

Associate Advisor

Ramesh B. Malla

Field of Study

Civil Engineering

Degree

Doctor of Philosophy

Open Access

Campus Access

Abstract

In marine systems, there is a need to characterize the system-level dynamic response of physical hardware components, such as critical mechanical equipment and vibration control devices. Pure numerical simulation of these components can be challenging and in many cases require full-system testing to characterize. However, full-system testing is often performed too late in the development process. In this dissertation, real-time hybrid substructuring (RTHS) is extended and demonstrated for marine systems to provide a cost-effective laboratory platform that combines physical testing and numerical simulation. RTHS is a relatively new method of vibration testing that allows a dynamic system to be partitioned into separate physical and numerical components or substructures. The substructures are interfaced together as a cyber-physical system using control actuation and sensing similar to hardware-in-the-loop testing.

This research specifically addresses the unique challenges posed by the real-time constraints of RTHS and its application to marine systems. These challenges include: 1) stability and performance analysis for both single and multi-actuator RTHS, 2) effective compensation of multi-actuator dynamics to ensure closed-loop stability and performance, and 3) efficient real-time solution of complex numerical substructures with acoustic fluid-structure-interaction (FSI). Since RTHS involves a feedback loop, a control systems approach is employed in the development of improved techniques to deal with these challenges.

To demonstrate RTHS, several laboratory experiments were conducted at the University of Connecticut Structures Research Laboratory. RTHS was used to experimentally verify a new application of the connected control method (CCM) for adjacent base isolation systems using physical damper hardware. RTHS was then demonstrated for marine structural acoustics using a physical mass-spring system coupled to different analytical fluid-loaded substructures of increasing model complexity. Experimental results demonstrate that RTHS accurately captures the system-level response and allows for repeatable tests of various dynamic conditions and potential system improvements to be efficiently examined.

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