Emulation of Recoil in Pyrotechnic Countermeasure Dispenser System

Sammanfattning: Developing countermeasures dispenser systems requires many and careful tests. When it comes to testing products with pyrotechnics, testing can often be very complicated and expensive. This might lead to no testing at all due to time or resource shortages. Products to be used in the military requires further testing and even more thorough reviews to meet the strict demands placed on the products. In order to enable more tests of pyrotechnic flares in the countermeasures industry, this degree project aims to increase the ability to perform tests without the need for pyrotechnic means. This was done by designing, constructing and optimizing a recoil emulator, an apparatus that imitates the force-time curve obtained by pyrotechnic flares without the need of pyrotechnic means. The construction of the recoil emulator was conducted at a department that develops countermeasure systems at Saab Surveillance in Järfälla. The apparatus aims to be used in the future for testing and verification of product series of countermeasures dispenser systems. The design of the apparatus was based on a test result provided by a flare manufacturer of an arbitrarily chosen flare, typical in the countermeasures industry. Based on the provided test result, three measures were chosen that together describe the fundamental and essential characteristic parts of the recoil motion behavior of pyrotechnic flares. These three measures are in the thesis called \textit{recoil measure} and defined as the Peak Recoil, the Impulse, and the Peak-Width. To be able to verify the recoil emulator, the three recoil measures were implemented in an error model, which was based on the squares of error. In order to make the emulator imitate the desired recoil motion behavior as pleasant as possible, the error model was implemented in an optimization model. By minimizing the error of data points from each of the recoil measures obtained from the real test provided by the manufacturer with results obtained from the recoil emulator, the emulator was verified and optimized accordingly. Results showed that the selected design of the recoil emulator resulted in a force-time curve that principally mimics the curve given by the real tests. The conclusion from the project was, therefore, that it is possible perform tests on countermeasures systems without pyrotechnics when considering the impact of recoil. Further development of this thesis could be to improve the construction of the recoil emulator and perform more research on flares and damping materials. Other future work could be to implement the emulator in existing test and validation processes at companies within the countermeasure industry.