基于等效单自由度的涡轮扫频振动研究

To solve the difficulties in obtaining turbine vibration under sweep-frequency conditions with the finite element method, a structural vibration frequency sweeping algorithm based on an equivalent single degree of freedom (SDOF) was proposed to analyze the characteristics of turbine vibration. Firstly, a fluid-structure coupling computational model of the turbine was established, obtaining the turbine surface's aerodynamic excitation with a non-linear harmonic method, and analyzing the steady-state vibration characteristics of the turbine surface with the harmonic response method. Then, an equivalent SDOF computational model was developed based on the energy principle for turbine. And comparing the computational model with the steady-state calculation method, its feasible and accurate was validated. Finally, the SDOF computational model was used to analyze the sweep vibration characteristics of turbine. The results show that, there are differences in the peak response, half power bandwidth, and response curve shape of the turbine between the conditions under sweep frequency and steady-state. The turbine response error calculated by the equivalent single degree of freedom algorithm and finite element method is less than 10%, and the formant offset is less than 1%.