軸心이 不一致한 船尾管 密封裝置에서 시일 링의 擧動과 應力解析에 關한 硏究

A Study on the Behaviour and the Stress Analysis of Seal Rings in the Eccentric Stern Tube Sealing System

To analize the behaviour of seal rings in the stern tube sealing system of which the propeller shaft is eccentric to the stern tube, stress analysis of axi-symetric body with non-symetric loading and non-symetric given displacements is investigated in this paper using the finite element method. As the non-symetric loads and non-symetric given displacements of axi-symetric body are generally periodic functions of angle e, the nodal forces and nodal displacements can be expanded in cosine and sine series, that is, Fourier series. Furthermore, using Euler's formula, the cosine and sine series can be converted into exponential series and it is proved that the related calculus become more clear. Substituting the nodal displacements expanded in Fourier series into the strain components of cylindrical coordinates system, the element strains are expressed in series form and by the principal of virtual work, the element stiffnes martix and element load vector are obtained for each order. It is also shown that if the non-symetric loads are even or odd functions of angle e, the stiffness matrix and load vector of the system are composed with only real numbers and relatively small capacity of computer memory is enough for caculation.