Compact Inflatable Structures for Submerged Payload Launch & Recovery
Navy SBIR NX191 - Topic NX19-001
Special Out of Cycle BAA
Opens: April 12, 2019 - Closes: May 13, 2019 (2:00 PM ET)


TITLE: Compact Inflatable Structures for Submerged Payload Launch & Recovery


TECHNOLOGY AREA(S): Ground/Sea Vehicles

ACQUISITION PROGRAM: Virginia Class Submarines

The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with section 3.5 of the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws.

OBJECTIVE: The U.S. Navy (USN) seeks to develop enabling technologies for the use of soft inflatable structures as components to undersea payload launch and recovery (L&R) systems. Inflatable structures using seawater as the inflation medium are particularly attractive to the USN because of their ability to produce large developable shapes possessing significant load-carrying capacities and stiffness when inflated and for their ability to achieve smaller form factors and volume reductions when deflated.

DESCRIPTION: The current state of inflatable soft structures technologies can provide unique solutions to many challenges limiting today’s Undersea Warfare (USW) launch and recovery operations.  Inflatable soft structures have been successfully developed for DoD, NASA, industry, etc. and are generally categorized in the following sectors:
• Inflatable control surfaces,
• Deployable energy absorbers,
• Temporary “on-demand” structures

Successful design and performance of soft inflatable structures is attributed to technological advancements derived from:
• High Performance Fibers (HPF) including but not limited to Vectran®, DSP® (dimensionally stable polyester), PEN (polyethylene napthalate), Spectra® (ultra-high molecular weight polyethylene), Kevlar®, and others,
• Novel fabric architectures and 3-dimensional preforms capable of unique mechanical behaviors,
• Continuous weaving processes for elimination of seams,
• Robust Physics-Based Modeling (PBM) methods with Fluid-Structure Interaction (FSI) capabilities,
• Material test methods for characterization of multi-axial mechanical behaviors for inputs to numerical models.

Collectively, these advancements have established a sound technology base; one that can be readily leveraged for innovative solutions to soft structure designs requiring significant load-carrying capacities, shock mitigation, dynamic energy absorption, rapid deployment, large deployed-to-stowed volume ratios, and fail-safe modes of operations.
This effort seeks to develop a soft inflatable structure, with a compact and predictable deflated shape, for payload recovery operations. The inflated and deflated configurations will be compared to established deployed-to-stowed volume ratios. The inflatable structures considered for use may include, but are not limited to, control volumes constructed of inflated skins, membrane bladders, coated fabrics, and hybrid (soft/rigid) material systems.  Hybrid structures may include inflatable elements with semi- or fully-rigid reinforcements serving as deployment shaping controls.  Seawater, supplied through an integral pump, will be the inflation medium.

The key challenge to taking advantage of their space saving potentials is managing the deflated shape and resulting form factor especially in the presence of crossflow velocity fields.  This challenge is increasingly difficult for larger structures that are not accessible to personnel as the inflated components are deflating.  Payload L&R systems operating at prescribed submergence depths require that the inflatable components function in a deterministic, repeatable and predictable manner in the undersea environment.

 The minimum operational constraints are:
• Inflation media is seawater
• Submerged operational depth: 100 ft (inflating and deflating)
• Operational cycles: 1000
• Minimum size of inflatable features: 6” diameter x 36” length
• Assist vehicle recovery via submarine standard 21-inch diameter by 25-foot long tube
• Crossflow velocity: 5 knots
• Inflate to full pressure in 15.0 seconds
• Maintain internal pressure for 24 hours
• Provide pressure relief for internal pressure exceeding 2.5x ambient pressure within 5.0 seconds
• Variance in deflated volume envelope: < 10% over 1000 operational cycles

The volumes of the soft inflatable structures at the inflated and deflated states will be determined through simulations, experiments and demonstrations. The developable shapes upon reaching the inflation pressures will be predicted through modeling simulations and measured from experiments. The deflated shapes and form factors will be predicted through modeling simulations and measured from experiments.

Work produced in Phase II may become classified. Note: The prospective contractor(s) must be U.S. owned and operated with no foreign influence as defined by DoD 5220.22-M, National Industrial Security Program Operating Manual, unless acceptable mitigating procedures can and have been implemented and approved by the Defense Security Service (DSS). The selected contractor and/or subcontractor must be able to acquire and maintain a secret level facility and Personnel Security Clearances, in order to perform on advanced phases of this project as set forth by DSS and ONR in order to gain access to classified information pertaining to the national defense of the United States and its allies; this will be an inherent requirement. The selected company will be required to safeguard classified material IAW DoD 5220.22-M during the advanced phases of this contract.

PHASE I: Proposers must provide concept designs, simulations of initial prototype designs, test results from laboratory experiments, and other relevant documentation to demonstrate that the proposed technical solutions are feasible for accomplishing the stated objectives and will meet the performance parameters set forth in the description.

By submitting Phase I proof of feasibility documentation, the small business asserts that none of the funding for the cited technology was reimbursed under any federal government agency’s SBIR/STTR program. Demonstrating proof of feasibility is a requirement for a Direct to Phase II award.

PHASE II: For this topic, proposers must meet the following program requirements for each round to be considered for the next round:
Round I: Select and optimize a soft inflatable structure including material selections, hydraulic layout design and manifolding (as required), inflation/deflation sequencing, hard-to-soft-goods connections for vehicle recovery from a notional launch tube. As stated in the solicitation, the period of performance for Round I shall not exceed 6 months and the total fixed price shall not exceed $250,000.

Round II: Identify operational, safety and environmental issues of proposed designs and will perform risk identifications, risk assessments and risk mitigation plans during the concept development stage. As stated in the solicitation, the period of performance for Round II shall not exceed 6 months and the total fixed price shall not exceed $500,000.

Round III: Prototype build of the proposed soft inflatable structure and testing to validate achievement of the deflation objectives stated in the description. The prototype soft inflatable structure including deflation capability shall be delivered to the US Navy for testing in accordance with the operational requirements stated. As stated in the solicitation, the period of performance for Round III shall not exceed 6 months and the total fixed price shall not exceed $750,000.

It is probable that the work under this effort will be classified under Phase II (see Description section for details).

PHASE III DUAL USE APPLICATIONS: Round IV: Installation of a final Prototype system into a submarine horizontal torpedo tube for operational test and evaluation for vehicle recovery. This Round may result in a limited number of licenses of the technology to allow for testing of the technology in various conditions and by multiple end users. The resulting technology will be of significant interest to the oil, power and telecommunications industries which rely on UUVs for monitoring and exploration of pipelines and cables on the seabed. Subsurface vehicle recovery would be a significant benefit.


1. Hulton, A., Cavallaro, P., and C. Hart, C. “MODAL ANALYSIS AND EXPERIMENTAL TESTING OF AIR-INFLATED DROP-STITCH FABRIC STRUCTURES USED IN MARINE APPLICATIONS.” 2017 ASME International Mechanical Engineering Congress and Exposition, Tampa, FL, November 3-9, 2017, IMECE2017-72097.

2. Cavallaro, P., Hart, C., and Sadegh, A. “MECHANICS OF AIR-INFLATED DROP-STITCH FABRIC PANELS SUBJECT TO BENDING LOADS.” NUWC-NPT Technical Report #12,141, 15 August 2013.

3. Sadegh, A. and Cavallaro, P. “MECHANICS OF ENERGY ABSORBABILITY IN PLAIN-WOVEN FABRICS:  AN ANALYTICAL APPROACH.” Journal of Engineered Fibers and Fabrics, vol. 62, pp. 495-509, March 2012.

4. Cavallaro, P., Sadegh, A., and Quigley, C. “CONTRIBUTIONS OF STRAIN ENERGY AND PV-WORK ON THE BENDING BEHAVIOR OF UNCOATED PLAIN-WOVEN FABRIC AIR BEAMS.”, Journal of Engineered Fibers and Fabrics, Vol 2, Issue 1, 2007 pp. 16-30.

5.  Avallone, Eugene A., Baumeister III, Theodore, and Sadegh, Ali M. Marks’ Standard Handbook for Mechanical Engineers, 11th Edition (Chapter: Air-inflated fabric Structures by P. Cavallaro and A. Sadegh), McGraw-Hill, 2006, pp. 20.108-20.118.

6. Cavallaro, P., Sadegh, A., Quigley, C. “BENDING BEHAVIOR OF PLAIN-WOVEN FABRIC AIR BEAMS:  FLUID-STRUCTURE INTERACTION APPROACH.”, 2006 ASME International Mechanical Engineering Congress and Exposition, Chicago, Ill, November 05, 2006, IMECE2006-16307.

7. Cavallaro, P., Sadegh, A. and Johnson, M. “MECHANICS OF PLAIN-WOVEN FABRICS FOR INFLATED STRUCTURES.” Composite Structures Journal, Vol. 61, 2003, pp. 375-393.

8. Quigley, C., Cavallaro, P., Johnson, A., and Sadegh, A. “ADVANCES IN FABRIC AND STRUCTURAL ANALYSES OF PRESSURE INFLATED STRUCTURES.” Conference Proceedings of the 2003 ASME International Mechanical Engineering Congress and Exposition, IMECE2003-55060, November 15-21, 2003, Washington, DC.

KEYWORDS: Undersea Payloads; Launch and Recovery Systems; Soft Structures; Inflatables