Emergency & Short-term Structural Repair System

Navy SBIR 25.1- Topic N251-049
Naval Sea Systems Command (NAVSEA)
Pre-release 12/4/24   Opens to accept proposals 1/8/25   Closes 2/5/25 12:00pm ET    [ View Q&A ]

N251-049 TITLE: Emergency & Short-term Structural Repair System

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Advanced Materials

OBJECTIVE: Develop a patching and repair system able to replace or strongly reinforce the original form and function of a damaged structure or component.

DESCRIPTION: Several past incidents (e.g., collisions, fires, drone/missile hits, and general material failure) have created hull penetrations and structural failures or scenarios where internal structural repairs are required on an immediate basis. The Navy seeks the development of a cost-effective durable patching and repair system that is convenient to store, can be easily applied to a variety of surfaces, and can be set or stiffened to the extent the patch material is able to substitute or strongly reinforce the original form and function of a damaged structure or component. The Navy seeks to develop a product that functions as a temporary repair in the event of a hull penetration or structural failure. The solution must be able to be applied while underway in a wide range of environmental conditions. The primary purpose of the repair will be to allow the ship to safely return to a destination where a more permanent repair is possible. Current commercial repair methodologies are not suitable for remediation of emergent damage while underway.

The solution should be able to be applied to a range of irregularly shaped openings and provide support for structural loads and restore the environmental integrity of the space. The repair system must stiffen to form a temporary but strong, durable, and water-tight seal. Examples of repairs include but are not limited to bracing, bonding, joining, encapsulating, plugging or patching. The repair technology will be required to be applied either indoor or outdoor and should cure regardless of temperature, humidity, and dampness. The desired product should fully cure within 1 hour. The solution must not emit toxic fumes during application and curing. Innovative joining and bonding methods are expected outcomes of this SBIR topic. The developed product should be applicable to all traditional ship steel and aluminum construction materials as well as support structures. Repair work should require minimal surface preparation such as degreasing, removal of foreign matter, or smoothing to allow for maximum contact with the patch material.

The repair material once cured should be resilient against normal pressures and in-plane ship motion/system stresses/loads. Repairs should survive wave slap green sea pressures of 4.65 Pounds Per Square Inch (psi) (normal to the deck) to 14.33 psi (normal to vertical surfaces/bulkheads), weapon blast pressures up to 20 psi, and survive a lap shear strength of the joint > 3 kilopound per square inch (ksi). In-plane structural stress levels expected are 7-9 ksi for aluminum structures and 20-30 ksi for steel. The largest damage to be addressed in this topic would be a 4’ diameter hole from a missile or drone penetration. The patch may or may not employ a system of ribbing for reinforcement to achieve the necessary strength; however, the ribbing must use the same patch material (either in flat sheets or geometric configurations) and must be able to be stiffened upon application within the same hour of set-time allotted for the primary patch. In repair applications, the repair must be resilient against tensile and torque forces.

Repair materials should meet Navy Fire, Smoke, and Toxicity (FST) standards. NAVSEA has published Design Data Sheet (DDS-78-1) to facilitate the transition of the new composite materials in U.S. Navy shipbuilding [Ref 3]. The material fire performance requirements described in this design data sheet are intended to provide consistent safety criteria for the application of composites aboard ships. These requirements have been developed based on Navy fire safety policy and international maritime standards for fire safety. Fire performance requirements for surface flammability, fire growth, smoke generation, fire gas toxicity, fire resistance, and structural integrity under fire have been established. Initial FST performance testing should include flame spread testing ASTM E162, E662, E800.

PHASE I: Develop a concept for a rapid damage repair system that meets the requirements in the Description. Demonstrate the feasibility of the operational concept with development and initial testing of the repair system. Demonstrate by Modeling and Simulation (M&S) or Finite Element Analysis (FEA) of the predicted performance of the proposed repair system to meet the requirements defined in the Description. The Phase I Option, if exercised, should include the initial layout and capabilities to demonstrate the application in Phase II.

PHASE II: Develop and deliver a prototype able to demonstrate the hardened patch material to the requisite specs, and ultimately be tested to failure. Evaluate the durability and how long the patch/repair holds. Perform a test plan as defined in Phase I to include applicable FST standards. Incrementally increase the stress loads to induce a failure point while observing and recording the failure. Prepare a Phase III development plan and cost analysis to transition the technology to Navy use.

PHASE III DUAL USE APPLICATIONS: Support the Navy in transitioning the Emergency & Short-term Structural Repair System for use on the Large Surface Combatant Modernization and Sustainment program. Strong temporary repairs that rapidly set have a wide range of applicability in the U.S. Navy as well as the commercial marine industry. The specifications cited are generally more rigorous and designed to allow for a strong temporary repair while a ship is underway and in a range of weather conditions. Such a repair will allow the ship to safely arrive at a destination where a more permanent repair is possible. The repair system also has universal applicability for non-maritime repairs.

REFERENCES:

1. Aabid, Abdul; Baig, Muneer and Hrairi, Meftah. "Advanced Composite Materials for Structural Maintenance, Repair, and Control." Materials 2023, 16, 743. 10.3390/ma16020743. https://www.mdpi.com/1996-1944/16/2/743

2. Cunha, L.G.; Alonso, R.C.B.; Pfeifer, C.S.C.; Correr-Sobrinho, L.; Ferracane, J.L. and Sinhoreti, M.A.C. "Contraction stress and physical properties development of a resin-based composite irradiated using modulated curing methods at two C-factor levels." Dent Mater. 2008 Mar; 24(3) :392-8. DOI: 10.1016/j.dental.2007.06.006

3. "DDS-078-1: Composite Materials, Surface Ships, Topside Structural and Other Topside Applications, Fire Performance Requirements, 11 August 2004." https://navysbir.com/n25_1/N251-049-Reference-1-Composite_Materials-Topside.pdf

KEYWORDS: Temporary Patch; Patching and Repair System; Ductile strength; Tensile strength; Emergent repair capability; Structural Patch.

** TOPIC NOTICE **

The Navy Topic above is an "unofficial" copy from the Navy Topics in the DoD 25.1 SBIR BAA. Please see the official DoD Topic website at www.dodsbirsttr.mil/submissions/solicitation-documents/active-solicitations for any updates.

The DoD issued its Navy 25.1 SBIR Topics pre-release on December 4, 2024 which opens to receive proposals on January 8, 2025, and closes February 5, 2025 (12:00pm ET).

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Topic Q & A

1/10/25  Q. 1. How are hull penetrations currently patched?
2. Does the Navy expect a Methacrylate adhesive would be sufficient for bonding patch material in place, provided the patch is strong enough?
   A.
  1. The Navy has not suffered an above the waterline combat-related penetration for a long time, perhaps the Vietnam or the tanker wars. When we’ve had accidents that result in penetrations, the damaged ship is either steamed back to port under their own power or it is towed/heavy-lifted back to port (preferably home port), and a Master of Ship Repair (MSR) is contracted remove the damaged sections and weld new structural steel and armor plating to repair the damage. For example, when the USS CHANCELLORSVILLE (CG 62) was accidentally struck by a target drone, it returned to port for repairs. The goal of this SBIR Topic is to identify a patch solution that allows decision makers the maximum flexibility to order a ship be patched to remain on station/in the fight or that it return to port for repair.
  2. There is no expectation that the adhesion of the patch system would be stronger than the adhesion of paint to the metal. Several other factors will be evaluated in addition to bond strength, and we understand that a product may be evaluated favorably based on bond strength but then less favorably in other areas, the goal of the SBIR is to identify the best overall patch solution.
Hull penetrations are generally sealed using traditional welds or gaskets. IN cases of hull breaches above the waterline where there isn’t a means to conduct weld repair, temporary metal plates can be attached to the ship structure using epoxy adhesives. Generally, these are in low stress application as most epoxy do not the necessary tensile strength to withstand any significant backpressure acting on the plate. The use of non-metallic adhesives for hull breaches is generally a temporary repair option. Final repairs are generally via traditional higher strength welds. I can’t speak to Methacrylate adhesive adequacy but suspect it is similar to epoxy and only used for temporary repair methods.
1/7/25  Q&A. Additional information provided by Technical Points of Contact for topic N251-049:

1. Shipboard Utilities
  • For installation, shipboard utilities such as power/compressed air will be available.
    • 2. Application Temperature Ranges
  • When applied, the solution could experience temperatures ranging from arctic to equatorial zone.
    • 3. Expected failure profile from a time perspective
  • Flexibility to have a long term patch is desired, though this is designed to be a short term solution.
  • Capability for longer term adherence is desired, due to the desire for fleet flexibility to maintain damaged ships on station.
  • Desire is for a patch that is able to be applied over the paint with minimal preparation; In this case, adhesion strength of the paint is the limiting factor.
  • In the case that the material must be applied to bare metal, this requirement must be noted and adhesion strength of the patch should at least be similar to paint.
    • 4. Storage
    1. Requirements for storage of product in refrigerated compartments or containers is not allowed
    2. Desired storage should be as small of a footprint as possible with no special humidity/temperature requirements
    5. Thickness
    1. Solution has no thickness requirements, only strength requirements as noted in the topic write-up, with the optimum solution to be as thin as possible so as to minimize storage space required.
    6. Multiple applications
    1. If curing is required, time to cure will be assessed. Multiple applications are assessed as 1 application from a cumulative cure time perspective.


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