基于光纤和柔性传感器的固体火箭发动机结构监测技术研究

Structural monitoring is of great significance for the structural reliability of solid rocket motors. Temperature, strain and stress of motor interface as well as strain on the inner hole surface belongs to important parameters for structural monitoring. The circular tube motor with inert propellant was used to monitor the motor interface structure by laying FBG optical fiber sensors and sticking flexible strain sensors in the inner cavity at the two interfaces of liner/propellant and insulation/liner, and the data of interface temperature, axial strain, hoop strain and principal stress, as well as inner hole hoop strain were obtained through temperature cycle loading test, which verifies effectiveness and applicability of the structural monitoring technology. The test results show that temperature and axial strain of the two interfaces are relatively consistent. The hoop strain consistency of the insulation/liner interface is significantly better than that of the liner/propellant interface, because the sensor is easier to be fixed in the former. The amplitude of the interfacial principal stress measured by the right-angle strain rosette is about 0.007 4 MPa, and the circumferential strain of the inner bore measured by the two flexible strain sensors is relatively consistent, with amplitudes of 13.4% and 13.8%, respectively, which can be used for large strain monitoring. The research results can provide technical references for the development of motor structure monitoring systems and the reliability of missile systems.