TECHNOLOGY AREAS: Ground/Sea Vehicles, Materials/Processes

ACQUISITION PROGRAM: PEO Combat Support & Combat Service Support

OBJECTIVE: Develop lightweight and volumetrically-efficient structures that can be applied to the underbody and sides of lightweight tactical vehicles that provide multifunctional structural load support and mitigation of blast impulses from roadside explosives events and buried mine blasts. The areal density of the structures must be less than 10 lb/ft2 and they must be able to reduce the level of blast energy that is transmitted to the crew compartment by at least 30% compared to a monolithic metal armor plate with the same areal density.

DESCRIPTION: The blast effects of roadside explosive events and buried mines can be eliminated by the use of thick armor and stand-off protection concepts but the resulting vehicles are then heavy, difficult too maneuver and difficult to transport by sea or airlift. New lightweight, volumetrically-efficient, structures are sought with enhanced impulse mitigation and blast energy absorption capabilities to provide protection to the occupants of lightweight tactical vehicles from road side bomb and buried mine blasts. This research would develop new lightweight structures that can used to construct, or be applied to, the underbody and sides of lightweight tactical vehicles that will provide load bearing properties and blast mitigation capabilities from roadside bombs and buried mine blasts. The areal density of these new structures must be less than 10 lb/ft2 and they must be able to reduce the level of blast impulse that is transmitted to the crew compartment by at least 30% compared to a monolithic metallic armor plate with the same areal density. The improved performance must be demonstrated experimentally in controlled blast experiments.

Progress has been made in the development of metallic sandwich panels with cellular cores. The benefits of these structures in water blast have been demonstrated and rationalized by the dynamic response of the core and face sheets[1,2]. Because of their tailorability, these structures offer a wide range of topological options for integrating blast protection in passive systems [3]. New multilayered structures made from high specific strength metals and ballistic fiber structures infused with impact resistant epoxy polymer systems are beginning to be realized [4]. Recent measurements on panels with square honeycomb and pyramidal lattice topologies have demonstrated that composite cores can be designed to realize strengths about an order of magnitude greater than their steel counterparts [5].

PHASE I: The successful contractor will develop and test the required number of proposed structures to meet the stated objectives of this STTR topic. The dimensions of the structures to be tested should be at least 2 feet by 2 feet with the minimum thickness dictated by the impulse transfer requirements. In addition, an technical cost model for the large scale manufacturing of the proposed structure should be provided.

PHASE II: Design, build, and evaluate the blast resistance of a prototype structure for a specific lightweight tactical vehicle such as the High Mobility Multipurpose Wheeled Vehicle (HMMWV) or Mine-Resistant Ambush Vehicle (MRAP). The performance of the prototype should meet or exceed the stated objectives of the SBIR.

PHASE III: Design build test and evaluate ballistic response of blast resistant structures.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: N/A

REFERENCES:
1. K. Nahshon, M.G. Pontin, A.G. Evans, J.W. Hutchinson, and F.W. Zok, "Dynamic Rupture of Steel Plates", Journal of Mechanics of Materials and Structures, 2, 2049-2066 (2007).

2. D.G. Vaughn and J.W. Hutchinson, "Bucklewaves" Eur. J. Mech. A-Solids, 25, 1-12 (2006).

3. H.N.G. Wadley, "Multifunctional Periodic Cellular Metals", Phil. Trans. R. Soc. A, 364, 31-68 (2005).

4. A.I. Marasco, D.D.R. Cartie, I.K. Partridge, and A. Rezai, "Mechanical Properties Balance in Novel Z-Pinned Sandwich Panels: Out-of-Plane Properties", Compos. A: Appli. Sci. Manuf., 37, 295-302 (2006) and J. LeBlanc et al, "Shock Loading of Three-Dimensional Woven Composite Materials", Composite Structures, 79, pp 344-355 (2007).

5. B.P. Russel and V.S. Deshpande, and H.N.G. Wadley, "Quasistatic Deformation and Failure Modes of Composite Square Honeycombs", J. Mech. Mat. and Structures, 101-126 (2008).

KEYWORDS: Road side bomb, mine blast, impulse mitigation, blast protection, blast, armor, tactical vehicle, blast mitigation, lightweight tactical vehicle, manufacturing technology.