December 2, 2024-Bryan Tomer, Carderock
December 2, 2024
4:00 p.m.
Room: Torgersen Hall 2150
Speaker: Bryan Tomer, Carderock
Faculty Host: Dr. Pat Artis
"Predicting Extreme Motions and Loads in Early Stage Ship Design"
Abstract: The process of designing a safe vessel does not just involve ensuring that it is stable under both intact and damaged conditions, whether that be in calm water or in waves. That process begins with the structural design of the vessel which must ensure that over the lifetime of the vessel, the structure is not over stressed even under the worst weather conditions that it could be expected to experience. A structural failure can lead to a vessel experiencing flooding resulting in a damaged stability issue or in the case of a total structural failure the catastrophic loss of the vessel. Adequate structural design depends on an accurate characterization of the maximum lifetime primary and secondary loads that the vessel might be expected to experience, the result of a superposition of multiple nonlinear processes.
Today, those loads are determined using empirical methods found in classification society rules, or from loads measured during model tests or predicted using a computational tool. As physical model tests and computational modeling are limited to relatively short periods of time relative to a vessel’s lifetime, the measured or predicted loads must be statistically extrapolated to determine their maximum values. This extrapolation is often performed using a Weibull distribution fit, and when an acceptable fit to the Weibull distribution cannot be obtained, the measured/predicted value is often just doubled. In the absence of a reliable statistical extrapolation method, a method of determining maximum loads is required.
Determining an accurate approximation to the exact single significant amplitude (SSA) motions for a vessel in an extreme seaway requires hundreds of thousands of hours of full-scale motion data. This is obviously impractical experimentally, as this amount of time exceeds the operational life time of a vessel and there is no way that “Mother Nature” could produce a statistically stationary seaway for even a tiny fraction of that amount of time. This leaves simulations as the only means by which such an extended period of time’s motion data can be produced in a stationary seaway. However, the fastest accurate motion- prediction tools run roughly one to ten times slower (CPU time/real time) than real time on high performance computer systems and the most precise prediction tools can run 10,000 or more times slower than real time. Therefore, it is impractical to use a high-fidelity motion prediction model to produce data for use in statistical validation. The solution of this dilemma is a reduced-order model that captures the most critical aspects of the physics of a ship operating in a seaway—particularly the geometric nonlinearities.
Bio: Mr. Bryan Tomer was selected in March 2021 as a Senior Scientific and Technical Manager (SSTM) for the Naval Surface Warfare Center, Carderock Division in the position of Director, Advanced Surface Ship Platform Concepts and Integration. In this position, Mr. Tomer provides leadership and oversight of the technical work, people, and organizations performing advanced maritime platform concepts, early-stage ship design activities, and technology integration efforts.
Early in his career, Mr. Tomer performed and then led numerous ship concept studies across a variety of naval missions and platform types in support of the Naval Sea Systems Command and Military Sealift Command. He then held a position at the Center for Naval Analyses (CNA) where he worked as a subject matter expert for naval platform design and technology integration on OPNAV sponsored Analyses of Alternatives.
Mr. Tomer next worked in the private sector as a Systems Engineering and Technical Assistance support contractor to the Office of Naval Research (ONR) serving as the Chief Technical Consultant to the Director of the Ship Systems and Engineering Research Division.
Joining Carderock in 2016, Mr. Tomer has served as a Team Lead for Future Surface Combatants and as a Technical Lead for Special Projects within the Future Ship Concepts Branch (Code 824). He is a graduate of the Florida Institute of Technology with a Bachelor of Science in Ocean Engineering and a Master of Science in Engineering from the University of Maryland.
The Naval Surface Warfare Center (NSWC) Carderock Division is the Navy’s center of excellence for ships and ship systems. For more than 100 years, NSWC Carderock Division has helped preserve and enhance the nation’s presence on and under the seas. NSWC Carderock Division is the full spectrum research and development, test and evaluation, engineering, and fleet support organization for the Navy’s ships, submarines, military watercraft, and unmanned vehicles with insight into new concepts and diverse technologies for the nations’ modern fleet. The Division’s expertise includes naval architecture and engineering, electrical and mechanical engineering, computer engineering, Naval materials, structures, and physics, as well as several other maritime concentrations.
NSWC Carderock Division’s unique laboratories, modeling and simulation facilities, at-sea-assets, and large-scale, land-based engineering and test sites at our headquarters in West Bethesda, Maryland, and seven detachment locations across the country contribute to the full-spectrum nature of our mission, allowing Carderock Division to continue to prioritize solving key operational problems to meet future fleet needs.
Navy and maritime communities have come to depend on our expertise and innovative spirit in developing advanced platforms and systems, enhancing naval performance, integrating new technologies, and reducing operating costs. For more than a century, NSWC Carderock Division has been at the forefront of technologies vital to the success of the U.S. Navy and Maritime Industry, and will continue to enable and empower tomorrow’s fleet.