Unattended Miniature Sensors

Not Available A magnetic flyer plate impact can be designed to accurately simulate the x-ray induced stress profile in a re-entry body (RB) heat shield very near the irradiation surface. With the accurate simulation of the near surface stress history all subsequent vehicle responses must then be a good representation of those induced by the nuclear threat. A Mag Flyer impact at atmospheric pressure is the highest fidelity simulation shapes the induced stress wave profile. A major limitation on the accuracy and repeatability of magnetic flyer plate experiments is that the load magnitude and temporal history are sensitive functions of the flight distance. When operating in air, the desired loading conditions can only be achieved with short flight distances and the normal RB tolerances limit the accuracy of the experiment. This proposal presents unique experimental solutions that allow the flyer plate distance to be significantly increased while maintaining the desired load magnitude and temporal history. These changes decrease the sensitivity of the magnetic flyer technique to flight distance changes due to experiment assembly and/or within tolerance dimensional variations and eliminates a major limitation of the magnetic flyer technique. The feasibility of using alternate gases and modifying the capacitor bank to tailor the gas spring response to allow larger flight distances will be examined in Phase I. Ktech's analyses have determined that the flight distance can be doubled by the use of an alternate gas such as neon. Capacitor bank modifications that modify the ringing frequency of the bank and/or shape the current pulse will also be examined because achieving constant flyer velocity at early times also facilitates the use of large flight distances. A Phase Ii program plan will be developed that describes the necessary modification to the DTRA Mag Flyer Facility to implement gas spring technology and the required facility characterization program. The gas spring technology will decrease the sensitivity of mag flyer techniques to dimensional tolerances of the test articles and will significantly increase the Mag Flyer Facility capabilities to meet specific experiment requirements in terms of peak stress and specific impulse. Additionally, load uncertainties will be reduced. The improved facility will provide a cost effective AGT capability for selection and hardness evaluation of new materials and the certification of modified systems.