TECHNOLOGY AREAS: Ground/Sea Vehicles, Materials/Processes, Battlespace

OBJECTIVE: To develop a clear understanding of the material response (all the way to failure) under conditions of high strain rate loading (equivalent to those experienced during wave slamming) with the ultimate goal of developing a standardized testing protocol that includes rigorous mechanics principles and affordable laboratory instrumentation.

DESCRIPTION: Current test standards used by industry for determining material mechanical properties of composite materials can be difficult and sometimes complex. Most methods that are used to characterize material properties are provided by the ASTM International or the former Suppliers of Advanced Composite Materials Association standards. These procedures are based on quasi-static loading and do not provide a complete characterization of the candidate materials, especially in the medium to high strain rate regimes that are now common to high performance military and recreational marine craft. Composite materials react differently to dynamic loading and can not be characterized quasi-static extension. Additionally, for large parts using heavy fabrics, the American Society for Testing & Materials (ASTM) testing protocol is inappropriate. A new procedure is needed to accurately characterize the response of materials in wave slamming and impact loads allowing optimization of marine craft design and fabrication.

This effort seeks to investigate the relationship of operational loading to structural and material response relative to the design and performance of high-speed marine vessels. The objective of this effort is to investigate and understand the principals of materials responses in the medium to high strain rate load regimes leading to the development of a standardized testing protocol. Special emphasis will be placed on vessels constructed of advanced composite materials utilizing glass, carbon, aramid, and hybrid reinforcements, in vinyl ester and epoxy resins. Vacuum assisted resin transfer molding is the process of choice, as it applies to the U.S. Navy and the commercial boat building industries.

An expected outcome is improved panel or coupon testing that supports the design and construction of high-speed marine craft subjected to slamming loads. The development of a test procedure and apparatus shall simulate "real life" operational conditions and allows the evaluation of various reinforcements, cores, resins and processing methods common to the marine vessel design.

PHASE I: Study, analyze, simulate and model the response of structurally significant composites components (reinforced composite sandwich component) to high strain rate loading environments equivalent to wave slamming rates. Define and characterize typical dynamic loading events. Produce a design intended for an affordable computer controlled laboratory instrumentation device that will allow the characterization of composite materials against high rate dynamic loading.

PHASE II: Evaluate the design in Phase I, introduce the necessary modification to the design and fabricate the high rate dynamic loading device which will be used as part of a standard test procedure. Complete the high strain rate dynamic loading models to simulate dynamic wave slamming events. Develop a material characterization test procedure for high rate dynamic loading that will validate the test procedure, mechanical models and the instrumentation by using standard Navy coupons.

PHASE III: Demonstrate this technology in a larger scale. Develop a modeling correlation between slamming / impact loading of composite panels to fatigue life. Establish a larger standard coupon that is appropriate to characterize large parts made with heavy fabrics. Initiate an addition to the ASTM testing protocol. Establish flaw criticality criteria and identify cost-effective Non-Destructive Evaluation (NDE) technology to quickly locate flaws in complex laminate structures. The Naval Sea Systems Command (SEA 05) and commercial shipbuilding entities would likely be very interested in a successful demonstration of this enhanced realistic composite material testing protocol.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: This phase is not funded by the SBIR program office. The PI will seek Navy program funding geared at demonstrating this technology in a larger scale.

REFERENCES:
1. Heller, S.R., Jasper, N.H., "On the Structural Design of Planing Craft", RINA, Quarterly Transactions, July, 1960.

2. Allen, R.G., Jones, J.R., "A Simplified Method for Determining Structural Design Limit Pressures on High Performance Marine Vehicles", AIAA/SNAME Advanced Marine Vehicle Conference, April, 1978.

3. Savitsky, D., Brown, P.W., "Procedures for Hydrodynamic Evaluation of Planing Hulls in Smooth and Rough Water", Marine Technology, Vol.13, No.4, Oct, 1976.

4. Garme K., Rosén A., "Experimental Pressure Investigation on High-Speed Craft in Waves", Proc. International Conference on Hydrodynamics of High-Speed Craft, RINA, UK, 2000.

5. Battley, M.A., Stenius, I., "Dynamically Loaded Marine Composite Structures", 14th International Conference on Composite Materials (ICCM-14), San Diego, USA, 2004.

KEYWORDS: structural composites, dynamic loading, wave slamming, mechanical behavior, modeling and testing

TPOC: Ignacio Perez
Phone: (703)696-0688
Fax: (703)696-0934
Email: [email protected]
2nd TPOC: Jeff Goldring
Phone: (202)781-3840
Fax:
Email: [email protected]
3rd TPOC: D Michael Bergen
Phone: (301)227-5057
Fax: (301)227-5548
Email: [email protected]

** TOPIC AUTHOR (TPOC) **

DoD Notice:   Between November 13 and December 9, 2007, you may talk directly with the Topic Author(s) to ask technical questions about the topics. Their contact information is listed above. For reasons of competitive fairness, direct communication between proposers and topic authors is not allowed starting December 10, 2007, when DoD begins accepting proposals for this solicitation.

However, proposers may still submit written questions about solicitation topics through the DoD's SBIR/STTR Interactive Topic Information System (SITIS), in which the questioner and respondent remain anonymous and all questions and answers are posted electronically for general viewing until the solicitation closes. All proposers are advised to monitor SITIS (08.1 Q&A) during the solicitation period for questions and answers, and other significant information, relevant to the SBIR 08.1 topic under which they are proposing.

If you have general questions about DoD SBIR program, please contact the DoD SBIR Help Desk at (866) 724-7457 or email weblink.