Separation Reliability Analysis for the Low-Shock Separation Nut with Mechanism Motion Failure Mode

A functional reliability simulation method based on the Kriging model is proposed to efficiently evaluate the functional reliability of low-shock separation nuts. First, a deterministic separation function simulation model of the separation nut is established. Second, the working load, geometric dimensions and propellant combustion parameters are introduced to establish the nonlinear implicit function of the separation nut in different separation stages, and the Kriging model is used to display the function. Finally, the functional reliability simulation workflow of the separation nut is established, and reliability and sensitivity analyses are performed to quantify the importance ranking of the working load, geometric size and propellant combustion parameters. It is shown that the influence of the uncertainties can be precisely described, and the preload and the support angle between the piston and nut flap play a dominant role in the separation reliability. This can further support the detailed design of the separation nut.