Dynamic Analysis Of Uncertain Structures And Research On Reliability Of Satellite Antenna Mechanism

Firstly, structures with interval parameters or interval-random parameters are taken as research objects in this paper. The structural dynamic characteristic and dynamic response are derived under the condition that physical parameters of structural materials, geometric dimensions of truss structures and applied loads are all interval or interval-random variables.Secondly, based on the engineering background of national 863 project, reliability computation, allocation, prediction and analysis on deployment mechanism system of satellite antenna are derived by means of non-stochastic theory. The main research works can be described as follows:1. The analysis of dynamic characteristic and dynamic response on interval truss structures.Under the condition that the uncertainty of physical parameters of structural materials, geometric dimensions of truss structures and considering uncertainty of applied load simultaneously, the structural stiffness matrix and mass matrix are constructed by using interval factor method. From the Rayleigh quotient of structural vibration, the computation expression of interval variable of structural characteristic is obtained on the basis of interval operation principles. From Duhamel integral, the expressions of structures interval dynamic response are deduced by combining mode superposition method with calculus, interval factor method and interval arithmetic, and membership functions of dynamic response can be derived in the end.Through some engineering examples, the influence of the interval structural parameters and interval applied load on structural interval dynamic characteristic and dynamic response are inspected.2. The study on dynamic characteristic and dynamic response of interval stochastic truss structures.Considering the interval randomness of the structural physical parameters and geometric dimensions simultaneously, the structural stiffness and mass matrices were constructed based on the interval factor method and random factor method; from the Rayleigh's quotient of structural vibration, the structural interval random dynamic characteristic was obtained by means of the interval arithmetic; the interval numeric characteristics of dynamic characteristic were then derived by using the random variable's moment function method and algebra synthesis method. From the Duhamel integral, structural dynamic responses are derived by the mode superposition method. Then, the interval numerical characteristics of interval random dynamic responses are derived by using the moment function method for random variables. Some numerical examples were provided to illustrate the validity and feasibility of the present method.3. The study on reliability index in the deployment mechanism of a large satellite antenna.Firstly, by studying the movement principium of hoop-truss satellite antenna, a mechanical analysis model of the deployment mechanism and the calculating formula for the interval forces of trusses were presented. Based on the function deployment of the hoop-truss must accord with, a movement reliability analysis model of the mechanism was given. Synthetically considering the effects of dimension errors and the space environment factors, we treated the mechanism movement-function as a function of some interval variables, and derived the reliability formula by using the method of non-probabilistic reliability. The movement reliability of the deployment mechanism was predicted and simulated in the whole process of deployment. Secondly, the seizure-preventing reliability of synchronous gears in the deployment mechanism is studied, from the ultimate position of the gearing mesh, the seizure-preventing condition for the gear pair is given in this paper. With gears'machining tolerances and fitting allowances and the space temperature considered synthetically, an analytical model of seizure-preventing non-probabilistic reliability of the gear pair is presented by using optimization. The seizure-preventing reliability of synchronous gears is predicted in different fitting allowances and different temperature conditions, and some significant conclusions are obtained.4. The study on the reliability allocation of satellite antenna deployment mechanism system.Fuzzy comprehensive evaluation method for system reliability allocation was proposed in the initial stages of the design of spaceborne antenna deployment mechanism. This method was based on the weight allocation method. Through introduced the fuzzy information into the matrix of weight coefficients, the fuzzy model for the reliability allocation of spaceborne antenna deployment mechanism was built. By the arithmetic operation rules of fuzzy mathematics, the expression of fuzzy weight coefficient was derived. Finally, the reliability allocation of a spaceborne antenna deployment mechanism was given as an example. The possible reliability of the system was obtained. The rationality and validity of the presented method were demonstrated.5. Interval analysis method of faulty tree for the deployment system of a large satellite antennaTo formulate the uncertainties of conventional fault tree analysis, the method of fault tree interval analysis based on D-S(dempster-shafer) theory and interval probability theory is proposed. On the condition that the premises in FTA(faulty tree analysis) is dependence or independence between basic events, the AND operator and the OR operator are proposed to compute interval probability of FTA, and upon which the system reliability was forecasted.6. Fault analysis of the deployment mechanism system of satellite antenna based on grey relation methodFor the shortage of the system reliability datum in the initial stages of the design of satellite antenna deployment mechanism, grey relation method for system reliability allocation was proposed. It was used to study the relativity of the mechanism system's failure characters and inside characters of the satellite antenna, and to confirm what kind of standard mode the actual mode belonged to. And it was also used in the fault tree's synthetically analysis.