Shock Mitigating Technology

The advancement of shock mitigation technology is critical to the protection of fuzes in future penetrating weapons that are smaller and faster than current weapons. The first objective of this project during Phase II is to continue the research anddevelopment of three shock mitigation approaches, and apply them to develop a mount or housing that protects the most susceptible component of a fuze, the accelerometer. The three fundamental approaches in Phase I that are proving to be powerful methodsof mitigating extreme shock loads are: (1) filter certain frequency bands with layers of materials having dissimilar impedances, (2) prevent or restrict energy flow to the device of interest using a momentum bottleneck, and (3) dissipate energy with ashape memory alloy in its superelastic mode or with other alloys that have high damping capacity. Our second Phase II objective is to understand the mechanical properties of encapsulates, which are typically rigid polymer foams cast into place around thecircuit boards and other components to protect them from shock. We will achieve this understanding by reviewing the literature, testing to fill in key data, and applying theories that predict the elastic properties and dispersive behavior of inhomogeneousmedia.