| While the performance of large-scale space equipment is greatly improved,the complexity of its mechanical system is also improved.In order to improve the reliability of the system and reduce the failure probability of the system,the hybrid system has been widely used in the design phase,and its main purpose is to increase the redundancy of the system.With the increase of system complexity,the probability of failure is also greatly improved.In view of the high maintenance cost of aerospace equipment,the research on its reliability is particularly important.However,the classical reliability theory still has some limitations,so we need to further improve the reliability theory to make it more in line with the engineering practice.In the reliability engineering of actual mechanical system,there are a lot of complex nonlinear correlations among the failure modes of various parts,which show the coupling of different failure modes,failure mechanisms and failure behaviors.In order to solve this problem,this paper takes the open and close shafting of a certain type of space telescope as the research object.When carrying out the reliability design,the nonlinear coupling relationship between various parts is considered,and the new reliability algorithm is used to improve the accuracy of the reliability analysis of the mechanical system,so that the reliability analysis of the system can be closer to its real reliability level.In this paper,the reliability of open close shafting is studied as follows:⑴Taking the telescope’s open and close shafting as the research object,the FMECA analysis and FTA analysis are carried out.At the same time,the hazard matrix qualitative analysis and the risk priority coefficient(RPN)are used for quantitative analysis.The two analysis methods are combined to identify the weak links and failure modes of the system.⑵The theory of Copula function is introduced into the reliability analysis of mechanical system,and the reliability calculation models of series system,parallel system and hybrid system are established.The r-vine copula structure is introduced to decompose the high-dimensional copula function,which is decomposed into the product of N pair Copula Functions and conditional Copula Functions,The timevarying parameters of Copula function in dynamic system are defined.The reliability of large-scale spatial opening and closing mechanism is calculated.The reliability data are obtained by Monte Carlo simulation method.The accuracy of dynamic r-rattan algorithm is proved by comparing the independent algorithm with the weakest link theory and using the boundary theory of mechanical system reliability.⑶Combined with Markov chain theory,the reliability is extended to the level of availability,and the availability model of repairable system with multiple failures is constructed.The relationship between the states of the system is described by state transition diagram and transition matrix.Based on the dynamic r-vine copula model,extended to the time-varying Markov process,the time-varying Markov models of series system,parallel system and hybrid system are established,and then the availability of open close shafting is analyzed.⑷Aiming at the problem of fatigue life assessment of rotating shaft components,static simulation was carried out by ANSYS,and the simulation results were imported into ncode design life software to further carry out co-simulation.The rain flow counting method(RF)was used to count the random load(white noise),and the stress fatigue(S-N)analysis was carried out based on miner cumulative damage theory. |
