The Optimized Design of the Thermal Buffer Pressure Measuring Tube of the Low Temperature Accumulator of Launch Vehicle

The accumulator is a key component to suppress the longitudinal coupling vibration of the rocket. In this paper,the modal analysis,fatigue life calculation and optimization design are carried out for the thermal buffer pressure measuring tube of the low temperature accumulator. Based on the finite element analysis method,the static pre-stress and random vibration stress spectrum density curves of the pipe were obtained. The Goodman straight line method was used to correct the static load,and the fatigue life of the pipe was calculated based on the Miner linear damage accumulation theory and the Dirlik method. Based on the dynamic equation of forced vibration,the concentrated expression form of the duct energy in the resonance state is derived,and the optimization and improvement direction of the pressure measuring duct of the cryogenic pressure accumulator is proposed. Through reasonable layout and optimized design,the natural frequency of the thermal buffer pressure measuring tube of the low-temperature accumulator is adjusted,avoiding the high energy area of vibration excitation,and greatly improving the anti-vibration fatigue performance of the tube.