Reliability Analysis Of Fairing Rotation Separation Under Multi-source Uncertainties

Fairing separation is one of the crucial parts during the whole process of the vehicle launch mission,whether safety separation would be directly related to the success of launch.With the increasing scale of vehicles,fairings are developing towards the direction of large-diameter and complex scales,and the sources and quantity of uncertainties on affecting separation are increasing.Although the rigid/flexible simulation technology of the fairing separation process based on deterministic analysis is relatively perfect,the systematic analysis of the uncertainty impact on the fairing separation is still deficient.Widely existing multi-source uncertainty factors will seriously affect the reliability of the fairing separation.However,the existing reliability analysis method is very time-consuming and has low calculation accuracy when analyzing large structures under the influence of multi-source uncertainty.Therefore,the reliability analysis of the fairing separation under multi-source uncertainties needs to be improved urgently.In order to explore the reliability of fairing separation process,this paper is based on the method of nonlinear explicit dynamic analysis,with the aid of ABAQUS finite element analysis software,in additional,with the dynamic dot-adding surrogate model technology.Considering the uncertainty factors which include dynamic deviation,manufacturing deviation,assembly deviation,and the environmental impact etc.,the goal of high-precision reliability analysis and configuration optimization of the redundant mechanism in the fairing rotation separation process has been achieved.The main research contents of this paper include:1)Fine rigidity,simplified rigidity and fine flexible finite element models are established respectively and simulation analysis with the help of ABAQUS is performed,besides,the separation characteristics obtained under ideal rigidity conditions is compared with the analytical solution obtained by energy conservation law,in order to verify the availability of the model and the feasibility of the simulation analysis.To obtain the rigid/flexible fairing separation characteristics and the flexible "breathing deformation"parameters,the modal analysis and nonlinear display dynamic analysis are performed.The results show that the deformation only affects the multi-top angular velocity but has no effect on the inner envelope.2)Form a dynamic dot-adding surrogate model suitable for the reliability analysis of the fairing separation has been constructed.Combined with the characteristics of multi-source uncertainties,an enhanced chaos control reliability analysis algorithm based on hybrid reliability model has been established.3)The failure mode of the separation system and the multi-source uncertainty factors that affect the separation characteristics are obtained by a large number of finite element analysis;The reliability of the fairing separation under the multi-source uncertainty and the influence of the power system on the reliability are analyzed by combining the proposed dot-adding surrogate model and the hybrid reliability analysis method.The results show that the current design is relatively conservative.Reducing 4 springs can still meet the reliability requirements,and also can achieve the purpose of reducing weight.