SBIR-STTR Award

Conventional instrumentation for airblast pressure measurements in cavity shots is limited in rise time capability. This results in the instrumentation providing an incorrect indication of peak pressure, which creates distortion in generated height-of-burst curves. The development of a fiber optic airblast pressure sensor based on the photoelastic effect is proposed. This technique promises to provide airblast pressure sensors with peak pressure measurement capability to as high as 20 kbar with a sub-microsecond rise time capability. This would offer a significant improvement to airblast pressure measurements on cavity shots. The proposed measurement technique has been successfully utilized on Underground Tests. On DISKO ELM the output detection scheme that will be used with these sensors demonstrated the measurement capabilities that will be achieved in the airblast pressure sensors.

The proposed Phase II program will develop fiber optic based procure measurement systems for use in free field airblast measurements of both aboveground and underground tests. In this program, a total of six airblast pressure sensors (three shock hardened and three radiation/shock hardened) and three opto-electronic interfaces will be developed and evaluated in both the laboratory and the field. Three of the measurement systems will be field evaluated on a DNA sponsored aboveground test at the Permanent High Explosives Test Site. The airblast pressure measurement systems that will be developed for this program will provide long duration measurement capability with a sub-microsecond rise time. This will be achieved using a "thin gauge" configuration. This provides a significant improvement to existing Hopkinson bar gauges. The measurement systems will allow improved height of burst curves to be generated from experimental data. The fiber optic measurement systems that will be developed under this program provide immunity to the effects of EMI and EMP, immediate compatibility with fiber optic data transmission lines, and a difference/sum output detection scheme that has proven reliability in both the conventional and the nuclear weapons test measurement environment.