Analysis Of Similarity On The Cable-cabin Structure Of The Large Radio Telescope

In this thesis, with cable described as catenary shape, a nonlinear mathematical model of the cable-cabin structure is established, and the cables' lengths and forces are calculated out through an optimal strategy on the distribution of the driving forces when the focus cabin moves along its trajectory. Thus the unlooped control of movement of the cabin is realized by adjusting the lengths of the cables coordinately.Based on the analysis of statics, dynamic model of the cable-cabin structure is derived by finite element method (FEM).Generic principles and conceptions of the similarity are introduced systematically. The emphasis is put on the three similarity theorems and the three derived methods of the similarity criteria.Based on the classical similarity theorem, the similarity criterias for suspended cable-cabin structure are derived from the equational analysis and the dimensional analysis. Numerical value for each parameter of the absolute similar model is advanced on the basis of similarity criteria.And the rationality of the similarity prediction is verified by the simulation through the finite element method.So the validity that similarity theorem is applied for suspended cable-cabin structure is demonstrated.For an especial problem that the model has many distorted factors, the expression of the forecastable coefficient for the cable tension and the structural natural frequency of the suspended cable-cabin structure is given by logical reasoning. Comparing the predictions with the simulation made by the finite element method, the validity of this method is demonstrated for a model with many distorted factors and large distortion ratio.The predictions of the cable tention and the structural natural frequency for LT500m are realized.