A growing concept in the field of unmanned air vehicles (UAVs) is the idea of using a team of cooperating vehicles to participate in electronic countermeasures, defined here as jamming or deception techniques. A UAV may be tasked to engage a radar using noise jamming to mask its radar return or that of another vehicle. Similarly, a UAV may be assigned to deceive a radar by directing a delayed signal toward the victim radar, which has the effect of producing a radar phantom perceived by the radar as an object at a false range and/or bearing. Previous work focused on generating a set of waypoints for the UAV to follow in order for the countermeasures to be successful. This paper addresses the path planning required to meet the temporal, spatial, and UAV flight dynamics constraints associated with employing these electronic countermeasures, especially between jamming and deception activities. The UAVs are assigned simplified flight dynamics and performance constraints in two-dimensions, assuming constant altitude flight over a flat-surfaced earth. All tracking radars are given simplified detection properties. A single UAV is provided a pre-determined series of "goal positions." The goal positions may lie along a countermeasure's pre-planned course or they may be established such that the UAV moves from the final waypoint of one countermeasure to the starting point of the next countermeasure. Therefore the UAV must autonomously navigate to a given goal position, subsequently perform a simple, associated task (countermeasure, if required), then navigate to the next goal position in the series. The UAVs will be required to arrive at these waypoints with a specific state, depending on the task at hand. Algorithms for optimal autonomous navigation of this nature were formulated to effectively guide the UAVs to their goal positions to meet the necessary temporal and spatial requirements. Simulations were generated to test the path-planning and control strategies given UAV/radar network scenarios, and overall UAV navigational performance in each simulation was analyzed. This material is declared a work of the U.S. Government and is not subject to copyright protection in the United States. Nomenclature Report Documentation PageForm Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OM...

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Functionally graded materials (FGMs) are advanced composites with mechanical properties that vary continuously through a given dimension. FGMs have generated a great deal of interest in recent years due to their flexibility for use in a wide variety of environments, including those structural applications where extreme thermal and corrosion resistance are required. In this paper, analyses will be performed given an impact event that occurs between a spherical projectile and a functionally graded circular plate with both simply supported and clamped boundary conditions. The circular plates are constructed using zirconia and aluminum as constituents blended through the thickness in various configurations using a power-law distribution. The analyses will assume that the classical rule-of-mixtures (ROM) approach will sufficiently describe the macro-mechanical properties for the graded plates. First, impact response equations developed for composite materials are applied to estimate the impact force and maximum deflection of a functionally graded plate. Next, the elastic wave response of the functionally graded plate is predicted using the classic wave equation applied to the graded plate and the impact event. Finally, finite element simulations are developed to compare the analytical solutions to numerical results from a commercial software program. The degree of correlation between the analytical predictions and the finite element simulations will provide insight into the validity of the ROM assumption and provide a baseline for estimating impact behavior of functionally graded plates.

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Hydrocode calculations for spherical shock propagation using the artificial-viscosity method are carried out to 0.2 psi overpressure for a nuclear explosion and for a TNT explosion. An ideal-gas integration from the literature is used to extend the results to 1.6 x 10-4 psi. Below 1.0 psi, 1 kt nuclear isequivalent to 0.7 kilotons of TNT. PUBLISHED