The Stability and Sensitivity Analysis of Structure Supporting Turbo‐generator with Regard to Parametric Effects

Abstract

AbstractThe paper is continuation of the research presented in GAMM'98. The problem of the influence of an axial vibration (axial dynamic loads) of the columns which are parts of the structure supporting turbo‐generator on the lateral parametric vibration this structure is analysed. The general conclusion is that the axial vibration changes the parametric steady‐state lateral vibration very much and it is inadmissible to neglect its influence. Moreover, the dynamic instability regions can be observed, despite of it that the magnitude of the whole axial force is only about 30% of the Euler's critical value for the column. The dynamic stability and the first order sensitivity analysis in the time domain of the steel, spatial, orthogonal frame supporting small turbo‐generator structure ]1[ shown in Fig. 1 is carried out. One column is extracted from the original structure, Fig. 2. Dimensions, stiffness and mass parameters of the strut are the same as in the structure supporting turbo‐generator. Rotary inertia of mass element at the top of the column and rotary stiffness of spring fixed the column are chosen to fit particular eigenvalue of the original structure, The axial and lateral sinusoidal changing forces, periods of which are commensurable, load this elastic fixed column. The FEM is used to solve the dynamic model. Numerical and analytical calculations are supported by the computer system “Mathematics”, “COSMOS/M” as well as author's software.