RSS机座拓扑结构对径向刚度和稳定性的影响

Effects of RSS support topological structure on radial stiffness and stability

以燃气轮机透平端RSS(旋转对称支承板)机座为研究背景,通过用D’Alembert原理建立了RSS机座的拓扑优化域和等价边界条件,从而用均匀化方法为基础的变密度法(SIMP)实现RSS机座拓扑结构优化,得到旋转对称的弧形支承板拓扑结构的机座。然后,在统一基本尺寸和边界条件下在ANSYS workbench中建立了三种不同的RSS机座拓扑结构的光滑有限元模型并进行了有限元分析、计算了中心标高的变化量,对比分析了三种RSS机座的对中性和径向刚度。同时,通过建立转子系统动力学方程,运用穷举法分析了三种机座支承参数对转子-轴承系统过临界振幅的影响,对比分析了三种机座支承最佳匹配刚度以及振幅的变化。通过分析可知,RSS机座的拓扑结构对机座中心标高、支承刚度和过临界振幅的影响很大。特别是,偏心率越大其影响也越大。偏心率的影响也影响最佳匹配的支承参数。这将为转子系统设计过临界振幅最小的RSS机座最佳支承刚度匹配提供参考。

Taking agas turbine end's RSS(rotating symmetric struts)support as the study background,the RSS support topological optimization domain and the equivalent boundary conditions were established by using the principle of D'Alembert,and the topological optimization of RSS supports was realized by using SIMP based on the homogenization method,then the topological structure of rotating symmetric arc-shaped strut supports were obtained.After ward,the smoothing finite element models of three kinds of RSS support'topological structure were established under the unity of the basic size and boundary conditions by using ANSYS workbench.The finite element analysis and calculations of center elevation variation were performed.The centering and radial stiffness of three kinds of RSS support were analyzed comparatively.At the same time,through the establishment of dynamic equation of a rotor system,the influences of three kinds of support parameters on the vibration amplitude of the rotor-bearing system passing its critical speed were analyzed with the EA(exhaustive attack)method,and the three kinds of the optimal matching support stiffness and amplitude changes were discussed.The results showed that the support central elevation,stiffness and the critical amplitude are greatly affected by its topological structure;especially,the larger the eccentricity ratio,the biggerits influences;the eccentricity also affects the optimum matching support parameters.The results provided a reference for designing rotor systems' RSS supports with the optimal matching support stiffness and the minimum critical amplitude.