| The docking lock of docking mechanism of space station is the key component of the permanent service space station under construction in China.It undertakes the tasks of docking,separation,transposition and redocking between each module,and is the core component to ensure the close connection between two adjacent aircraft.The design operation life of the space station is 15 years.Therefore,the docking lock must be able to operate safely for 15 years under the working condition.In view of the above requirements,this paper focuses on the service life of the docking lock,from the aspects of the mathematical model of the docking lock life prediction,finite element simulation analysis and accelerated performance test.(1)Establishment of mathematical model for transfer path and life prediction of locking force of butt lock Taking the docking lock of docking mechanism of permanent service space station as the research object,according to its working principle and bearing condition,combined with the generation mechanism of locking force of docking lock,the force model of docking lock is analyzed,and the force transfer path of locking force is established;based on the force transfer path and the performance degradation mechanism of each part of docking lock in stable service stage,the mathematical model of long life prediction is established.(2)Solution of mathematical model for life prediction of butt lock The stress relaxation/ creep test data of disc spring,titanium alloy TB2,TC4 R and aluminum alloy 7A04 were analyzed by acceleration theory and material creep and stress relaxation theory.The life degradation equation and the stress relaxation value of each part in the service cycle were solved respectively.Then the equivalent elastic modulus E ’of the corresponding parts after stress relaxation was obtained by combining with the finite element method The mathematical model of lock life prediction is solved numerically,which provides a theoretical basis for the life prediction of butt lock.(3)Finite element simulation of locking force attenuation of butt lock Using the finite element software ABAQUS,combined with the material performance test of docking lock components,the accurate performance parameters of each material are obtained,the static characteristics of docking lock of space station docking structure are studied,the strength of the docking lock in the locked state is checked,and the locking force in the initial state is obtained;according to the performance parameters of each part of the docking lock in different service stages,the service cycle is carried out Through the simulation analysis of the docking lock force attenuation,the attenuation of the locking force is solved,and the accuracy of the simulation analysis of the docking lock force attenuation is verified by comparing with the results of the theoretical solution of the mathematical model.(4)The accelerated degradation test analysis of docking lock The accelerated degradation test of docking lock is carried out with temperature as the accelerated stress.Based on the test data under high stress level,the life of docking lock under normal service conditions is predicted based on the Arrhenius accelerated model.The correctness of the finite element simulation analysis results of force attenuation is verified,which provides the basis for the life prediction of docking lock of space station docking mechanism. |
