Multicomponent and Multifailure Mode Reliability Analysis of Rear Variable-Area Bypass Injector

The rear variable-area bypass injector (RVABI) is an important component of the variable-cycle engine, and its kinematic accuracy and reliability have an important impact on the performance and function of the aeroengine. The RVABI consists of several components and has various failure modes. To study in detail the influencing factors and influencing mechanism of the motion accuracy reliability of the RVABI, based on the screw theory, the kinematic model of the mechanism is established, and the attitude function of the mechanism at the driving end under ideal conditions is obtained; based on the extended application of the theory of the effective rod length, the calculation methods of the influence of various errors are investigated, as well as the equivalent component method to establish the motion performance function of the mechanism under the joint influence of error parameters and mechanism parameters. The correlation between the error probability distribution and the set of vector points for different failure factors is described using the probability density space (error surface). Finally, based on the Monte Carlo simulation method, the positioning accuracy of the multicomponent, multifactor coupled mechanism was simulated and analyzed, and the positioning accuracy reliability of the mechanism was calculated.