Energy Dynamically-Tuned Absorbing Sheet for Underwater Implosion Mitigation(1001-436)

Triton Systems Inc., with Draper Laboratory, proposes to develop a SOF mission equipment container containing damping mechanisms to neutralize the adverse effects of stored equipment implosion. This container will be a flexible bag that can be rolled up while not in use, provides a rugged waterproof envelope, contains harmful outgassing, and incorporates fire retardant elements. The basic concept is to enclose the implodable equipments with a layer of material having large hysteresis in its stress-strain behaviour. Candidate materials include rate sensitive reticulated elastomers, plastic honeycomb-like, and cellular polymeric materials. Static stiffness will be tailored to accommodate the operational depths/pressures, and the dynamic stiffness will be defined to absorb the requisite implosion energy at a TBD thickness. A simplified dynamic model of the implodable volume/container/swimmer system will be formulated to provide parametric assessment of the bag performance. Likely diver injury mechanisms due to an implosion will be evaluated to identify the thresholds of dynamic response. Candidate material stackups will be fabricated in Phase I and subjected to instrumented drop weight testing to validate their performance. During the Phase II a pre-prototype equipment container with implosion mitigation will be fabricated and subjected to operational loadings to evaluate compliance with the solicitation requirements.