Hull Life Assurance Thrust

Overview

• Design solutions for less susceptible, more survivable ships with reduced life cycle costs. The focus is on developing non-magnetic hulls and low-observable topsides.
• An increase in the phenomenological understanding of the physical behavior of marine systems in order to transition towards simulation-based design and accelerate the insertion of technology into new platforms.

Hull Structure Technology

Welded, stiffened, steel ship hulls have been the standard construction method for Navy ships for the past 60 years. Recent Navy interest in balanced, total-spectrum signature reduction as well as the need for life cycle cost savings has resulted in the development and consideration of alternative materials and geometries for use in hull applications. Initiatives include:

• Composite Primary Hull — Composite materials offer an alternative approach to hull design, with benefits that include lower magnetic signatures and potentially lower life cycle costs. The current focus is on assessing composite hull structures subjected to UNDEX loading and developing failure prediction tools and design guidelines for composite structural joints and details.
• Hybrid Hull — Hybrid steel/composite options are also being explored. This offers signature and cost benefits similar to those available from the parent technologies but with the added benefit of being able to selectively tailor structural solutions to specific areas on the ship. For example, combining a SSADH mid-body with a composite bow and stern would provide a reduced-magnetic-signature hull with a method to economically manufacture the complex geometry associated with the bow/stern shapes being considered for new combatants. An alternative hybrid approach being investigated consists of attaching composite panels to a steel framework in order to facilitate simple manufacture and repair.

Topside Structures

The primary focus of the Topside Structures area is to develop and demonstrate technologies that enable future combatant topsides to achieve their specified performance levels in the areas of RF and IR signatures, topside weight, and life cycle costs. Initiatives include:

• Reliability-Based Design — This initiative will develop the ability to statistically define the probability of survival under environmental loads for intact or damaged hulls over the operational lifetime of the ship.
• Composite Structural Performance — This initiative will establish the thermo-mechanical behavior of polymer matrix composite structures in the marine environment. It will provide models for the prediction of the response of composite structures to static, dynamic, and cyclic loading in severe environments, including extremes of temperature, moisture, seawater, and hydrostatic pressure.
• Structural Analysis Codes — This initiative will advance the phenomenological understanding of the physical behavior of marine systems and platforms and advance related predictive and simulation capabilities.
• Analytical Methods to Predict Weapons Effects — This initiative will develop an understanding of the failure modes and mechanisms of current and advanced ship structures subjected to underwater and air-detonated weapons.

Also See:

• Basic Research Descriptions For:
  • Structural Mechanics
  • Computational Mechanics
  • Composite Mechanics

Point of Contact:

Program Officer
Phone: 703-696-0813
E-mail: 334HL@onr.navy.mil