Techniques for Missile Defense (Flexible-Body Dynamics for Off-Nominal Penaid Signature Simulation)

"Algorithm development for midcourse discrimination requires large libraries of signatures (i.e., time histories of reflected and/or radiated optical intensity or radar cross-section) accurately incorporating the properties of deployed objects, includinglow mass decoys erected or inflated from small-volume stowage.The dynamics of such objects plays a critical role in signature determination. Current signature codes model only rigid body motion, which may be inappropriate for decoys made of flexible materials, particularly after suffering an off-nominal deploymentand concurrent shape distortion.Under a current Phase I SBIR contract PRA is installing the capability to automatically create ensembles of off-nominal decoy models for rapid generation of suites of signatures with appropriately varying properties. In this proposal we describe aparallel effort to develop a fully compatible non-rigid body motion (NRBM) simulation capability for PRA's VISIG signature code. When integrated with the other work, this will allow high-fidelity simultaneous modeling of both static and dynamic structuraldeformations, fully including effects of flexure on the rotational state of the object and vice-versa. Dynamic effects on signature through object shape changes are also included. The proposed development will add a unique, computationally efficient,non-rigid body motion (coupled flexure and rotation) capability to a set of tools used to generate s