A Time-varying Failure Rate Analysis Method for Dynamic Coupling of On-orbit Space Flexible Gear Mechanism

Abstract

A dynamic coupling time varying failure rate analysis method of a on-orbit space flexible gear mechanism comprises the seven steps that firstly, according to the fact that a shaft in the on-orbit space flexible gear mechanism is an elastic body, a kinetic equation of the flexible shaft is built, and the finite element method is adopted for analysis; secondly, a gear kinetic equation is built; thirdly, a nonlinear kinetics equation of coupling of the flexible shaft and a gear in the on-orbit space flexible gear mechanism is built; fourthly, transmission stimulation analysis is performed on the space flexible gear mechanism; fifthly, the Newmark algorithm is adopted to calculate a dynamic load coefficient; sixthly, a gear bending stress reliability limit state function is built in the on-orbit space flexible gear mechanism; seventhly, dynamic reliability and failure rate analysis are performed on the space flexible gear mechanism. The method solves the problem that reliability calculating accuracy is low because of nonlinear factors of a traditional transfer matrix method and mode superposition method, and has engineering practical value for improving reliability of the on-orbit space flexible gear mechanism and other spacecrafts. The method is also suitable for other flexible gear mechanisms.

Description

technical field [0001] The invention relates to a dynamic coupling time-varying failure rate analysis method of an in-orbit space flexible gear mechanism, which involves elastic body dynamics and time-varying reliability simulation analysis of an in-orbit space flexible gear mechanism, and belongs to the field of reliability design and analysis of space agency products . Background technique [0002] Flexible gear mechanism is a typical on-orbit space flexible mechanism, and its reliability level is directly related to the safety and mission success of spacecraft such as on-orbit space satellites. Therefore, its on-orbit reliability design analysis is one of the prerequisites and key technologies to ensure the reliable operation of the on-orbit space mechanism. The gear meshing process in a flexible gear mechanism is a typical dynamic response process, and the failure rate presents a time-varying characteristic that changes with time. The traditional PHI2 method can only ob...

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Problems solved by technology

Considering the dynamic characteristics of the space flexible gear mechanism and the gear meshing problem of the elastic deformation of the long rotor is a highly nonlinear problem, the present invention first uses the elastic body vibration model and the spur gear plane vibration model to establish the flexibility of the gear meshing process. The nonlinear dynamic equation of shaft and gear rigid-flexible coupling; and use the numerical method to analyze the dynamic stiffness excitation, error excitation and external excitation of the gear. On this basis, use the Newmark method for simulation calculation to obtain the dynamic load coefficient of the gear; secondly , aiming at the time-varying and strong nonlinear characteristics of the dynamic load coefficient, the kriging method is used to solve the reliability index at a certain moment, which avoids the problem of low reliability calculation accuracy caused by nonlinear factors in the traditional transfer matrix method and mode superposition method; finally , in view of the time-varying characteristics of the failure rate during the movement of the space flexible gear mechanism in orbit, the present invention proposes a new time-varying failure rate algorithm, which can obtain the time-varying characteristic law of the failure rate of the flexible gear mechanism. The reliability has a certain guiding significance and engineering practical value

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