Test Method For Solid Propellant Parameter Overload

Solid propellant grain is the power and the main bearing member of solid engine rocket. When solid propellant grain was working in overloaded launching condition, The dynamic mechanical properties of it is closely related with performance of internal ballistics inside solid engine rocket. So far in order to research the dynamic characteristic parameter in overloaded launching condition, researchers abroad mostly use hard-line testing technology. Limited with working-Environment of engine, Cables of signal transmission are easily shaking, Wrecked during the period of Actual measurement. System of test shows low capture rate and reliability and so on. Aiming at the question above and based on Analog transmission analyze, this text proposes the test method of dynamic parameters of propellant storage.Through establishing load environment of air-cannon test, simulated the actual overloaded launching process of solid rocket motor. For engine charging structure.After carefully analysis to the acceleration changes and the characteristics response to the dynamic strain in simulating and overloaded launching condition, we proposed indicators of performance, principles of design and the whole program of dynamic parameter detection to propellant grain in simulating launching condition. Based on electrical characteristics of output signal to sensor, we designed corresponding conditioning circuit, reducing the huge non-linear error of traditional constant-pressure bridge strain electrical measuring circuit during the testing of large strain to propellant. The research designed a test circuit with FPGA as control core, completed system’s signal trigger level detections multi-clock synchronization and control, completed the test data collection and storage through A/D conversion and SDRAM operation, and realized the test data upload through USB data communication port. It designed a effective power management module to guarantee the stability and efficiency of the system work. With a view to the particularity of working environment of the system, the SolidWorks2008was used to design the protection shell structure after layout planning the mechanical structure of each module, and the appropriate encapsulating technology was chosen to improve the whole overload resistance of the device. On the basis of the hardware circuit design, Verilog hardware description language is used to write the FPGA program in QuartusII9.0software environment, and PC data processing software was developed on the platform of LabView8.6, ensured the storage test system running normally. Signal generator, shunt resistance method and drop hammer signal generator was used in test system for the commissioning, static calibration and functional verification. The test results show that the design is feasible on principle, and test system has practical use value, which can provide a kind of effective testing method and mean for motor propellant under simulated launch overload condition of dynamic parameters of quantitative detection.