Real-Time Health Monitoring for Solid Rocket Motors

ABSTRACT: A Health Monitoring Sensor for Solid Rocket Motors (SRMs) uses actual polymeric components of propellant in a tiny new sensor called AgeAlert. These sensors will provide real-time data corresponding to aging of the propellant. The sensors are mounted external to the propellant and automatically track degradation passively without electrical power until interrogated. They are extremely accurate because they degrade in the same way under the same environment as the propellant in motor itself. AgeAlert sensors are attached to a rocket motor so they"see"the same environment as the propellant being monitored. Applications include (1) data for verifying existing and proposed SRM health management models based on environmental sensors and (2) stand-alone"Smart Shelf-Life"labels attached to small ordnance items or packaging to monitor aging of the propellant during transportation, storage and deployment. These smart labels provide immediate"go, no-go"indication to the user in the field without special training or equipment. This project expands on successful research by Polymer Aging Concepts, Inc. for prototype sensors to monitoring aging of electrical insulation materials in nuclear power plant components. Participation by a SRM prime contractor in the selection propellant materials and sensor data correlation optimize probabilities of success and technology implementation. BENEFIT: These innovative sensors will greatly advance Integrated Vehicle Health Management (IVHM) of solid rocket motors and potentially save up to 50% of the cost of present methods utilizing destructive testing while improving reliability and safety of military and commercial solid rocket motor assets. The accuracy and in-situ features of AgeAlert technology means that not only will operators in the field benefit with a smart label which provides continuous status as to the reliability and safety of solid rocket motor ordnance, but objective data is readily available on individual assets to support mechanistic modeling for surveillance and shelf life extension programs. It will reduce the need for embedded sensors which add complexity and uncertainty due to stress risers in operational assets. This new heath monitoring approach is very cost effective since (1) the sensor utilizes inexpensive fillers used in the composite sensors, (2) sensor smart labels and readers are simple and reliable because they are based on the inherent"variable resistor"output of the sensors, and (3) field interpretation of"Smart Shelf-Life"labels utilizing AgeAlert sensors is simple pass/fail requiring no special operator training or equipment. Since no electrical power is required to respond to the degradation, the sensors can be incorporated into passive (no battery) radio frequency identification (RFID) devices allowing a single smart label to uniquely identify the item and identify significantly degraded items before reliability or safety are impaired. Potential commercial applications include sensors and smart labels for military and commercial solid rocket motor assets. The approach of this proposal could be expanded to monitor aging of other propellants used in ammunition, fuses, explosives and pyrotechnic devices. Since AgeAlert technology is potentially applicable to any product comprising polymeric components, future health monitoring applications include advanced composite structural materials, seals, gaskets, tires, protective coatings and electronic packaging. Strong intellectual property and process"know-how"in fabricating AgeAlert sensors provides significant opportunity for high technology domestic manufacturing jobs.