By Priya Hicks Program Lead, Electric Boat Independent Research and Development
Measuring success in innovation is hard. Pairing this difficult task with innovating in an undersea domain that is a dynamic system-of-systems environment, which includes submarines, which are their own complex engineering challenge, creates a thought-provoking job for any program manager. At Electric Boat, the complexity of the product and inherent uncertainty of exploring new technologies and methods requires constant vigilance on the innovation front. One component of the innovation engine at Electric Boat is Independent Research and Development (IR&D), a cornerstone of the company's R&D efforts for decades.
R&D is a source of potential solutions for the technology challenges faced by the Department of Defense (DoD). IR&D costs are allowable as indirect expenses, and companies have the independence to decide which technologies to pursue as long as the efforts are of potential interest to the DoD. IR&D does not include work that is part of a federal contract, so any technical data rights remain with the company. Selecting IR&D projects is the sole responsibility of the company conducting the IR&D work. To increase the chances for transition, however, it is important for companies to keep their DoD customers aware of promising technologies and integration efforts.
At Electric Boat, the IR&D portfolio is set up to integrate new capabilities into the way the product operates through designing the best platform and the way the product is built. Building an IR&D portfolio starts with developing an internal Request for Proposal (RFP) that takes into consideration the goals from the company’s strategic plan, technology development needs from Electric Boat’s concept development group and from lessons learned from our larger submarine development programs, and customer needs and perspectives from the Navy’s strategic science and technology documents. The RFP is then released to the entire company for project ideas that not only are aimed at delivering value to the company and the customer but take affordability and the end user into mind.
This article will showcase three different submarine-related IR&D successes at Electric Boat.
Propeller Crashback Simulation
In 2007, computational fluid dynamics engineers at Electric Boat achieved a milestone in the simulation of propeller crashback. Propeller crashback is the sudden reversal of rotation by marine propellers, usually performed under emergency conditions. This maneuver creates large-scale unsteady flow structures when the propeller operates in the reverse direction, generating large side loads that result in high peak blade stresses and impact the maneuvering performance of the vehicle. Using computational methods to predict these types of forces was limited in the past due to the substantial computational resources required for accurate crashback flow simulations. The engineers were able to capitalize on the supercomputing power at the Naval Oceanographic Office Major Shared Resource Center (NAVO MSRC) in conjunction with Electric Boat’s IR&D-funded computational fluid dynamics (CFD) solver.1 The engineers were able to accurately resolve the ultra-low-frequency propeller side force generated during crashbacks using a zonal variant of the Detached Eddy Simulation (DES) turbulence model2
This was a milestone because the side forces generated during crashback were not well understood at the time and have significant implications in propeller design and marine vehicle maneuvering. The methodology was not only a breakthrough for propeller analysis but can also be applied to pumps, complex internal fluid flows, and control-surface design. The engineers were able to use this method to assess the main feed pump on USS Virginia (SSN 774) and also in the design of the Ohio Replacement control surfaces. At large angles of attack, control surfaces can have large separated flow structures, much like the structures examined in the crashback study. The methodology developed for the crashback scenario applies to this type of problem and ensures that simulations are as close as possible to real-world conditions. This is essential to ensure that design margin can be safely eliminated from designs in order to still produce and deliver an affordable, safe product.
Large Aperture Bow Array
A second successful example, which highlights a technology that was integrated into the platform, is the development and integration of the Large Aperture Bow (LAB) array on Virginia-class Block III. The LAB array change accounted for $11 million of the $200 million cost savings goal for the Virginia-class design. This bow redesign was not only the number one technology-based cost saver leading to a $2 billion Virginia-class, but it also opened up the front end to enable the insertion of large flexible payload tubes. The array concept was initiated under IR&D in 2003 and 2004.
Engineers at Electric Boat worked through various concepts to eliminate different space-consuming features from legacy bow arrays to create an array that returned more arrangeable volume to the submarine but also to develop a more capable array. Using their initial IR&D work as a springboard for discussions with the Navy, the concept was so compelling it was rapidly transitioned to contract R&D in 2005. The contracted R&D funding allowed further development of the concept and in-water testing of the concept. Hundreds of SUBSAFE penetrations were eliminated as part of the design, and life-of-the-hull transducers were integrated into the design. This technology was first delivered on USS North Dakota (SSN 784) in 2014.3
Figure 4. Virginia Block III Bow Redesign
Fly-by-wire Ship Control Stations
In a third example, IR&D funding was used at Electric Boat to initiate innovation that was then carried down through different submarine programs. This effort started with IR&D in the 1980s when Electric Boat was investing in advanced fly-by-wire ship control stations. Over the course of 10 years, Electric Boat invested approximately $3 million on research and technology integration for future ship control stations. This work under IR&D was the initial steps for the first Virginia-class fly-by-wire ship control station. The work done for the Virginia-class was leveraged for the Ohio Replacement ship control station.
The fly-by-wire transition enabled integrated fault detection and isolation during operation. To keep innovation moving for future ship control stations, Electric Boat is currently funding efforts to integrate next-generation automation into ship control and also take advantage of advances in human systems integration to create a more user friendly environment for future Submariners.
To turn vision into reality, Electric Boat is partnering with industry and academia to ensure that future ship control stations benefit from the best, most affordable technology solutions.
It is important to not be complacent with the successes that have already come to fruition. At Electric Boat, we are aiming to understand all of the customers’ needs today and tomorrow to align our IR&D portfolio investments to provide the best product. The Navy strategic documents that are available through the Defense Innovation Marketplace, including the Navy Science and Technology Strategic Plan and Undersea Warfare Science and Technology objectives, provide invaluable insight during portfolio development. Two annual crowdsourcing events with our entire workforce and also our summer interns keep the innovative ideas flowing to feed the IR&D program. Going forward, capitalizing on the talent and passion of our young workforce paired with mentoring from our top-tier experienced engineers will help de-risk the R&D of advanced technologies. There are many more examples of success in IR&D at Electric Boat and numerous examples of success in failure. IR&D is not the place to “play it safe” but to shake out and verify new ideas for the fleet. Success is achieved through partnerships with technology providers, academia, and the labs, and these partnerships play a crucial part in developing more success stories.
1 Slimon, Scot A. and Craig Wagner. “Crashback Maneuvers.” NAVO MSRC Navigator, Spring 2007, pages 5-7.
2 Slimon, S.A., “Computation of Internal Separated Flows Using a Zonal Detached Eddy Simulation Approach,” Proceedings of International Mechanical Engineering Congress and Exposition (IMECE), 2003 American Society of Mechanical Engineers (ASME) International Engineering Congress and Exposition, Washington, D.C.
3 “VIRGINIA Block III: The Revised Bow.” Defense Industry Daily, 21 December 2008, http://www.defenseindustrydaily.com/virginia-block-iii-the-revised-bow-04159/.