改进的混合界面子结构模态综合法在失谐叶盘结构模态分析中的应用

在保证精度的条件下,为了提高航空发动机模态分析的计算效率,针对传统混合界面子结构模态综合法由于综合后还可能存在计算量大的问题,提出一种改进的混合界面子结构模态综合法。该方法将综合后的模型进一步减缩,同时在减缩过程中引入位移和力的双协调条件,保证了计算的准确性。采用该方法建立了叶片-轮盘的组合结构的参数化模型,对各个子结构建立有限元模型并综合求其模态,与整体结构有限元法相比,计算时间缩短了23.86%~35.74%,模态偏差不大于0.57%,而传统法,其计算时间缩短了14.63%~29.20%,模态偏差不超过0.49%,可见,在相同的工作环境且保证精度的条件下,该方法计算效率比传统混合界面子结构模态综合法有显著提高,尤其是在高阶模态求解时,计算效率提高的更加明显,为下一步的振动响应及组合结构的动态特性研究奠定了基础。

APPLICATION OF IMPROVED HYBRID INTERFACE SUBSTRUCTURE CMS METHOD IN THE MODAL ANALYSIS OF MISTUNED BLADED DISK ASSEMBLIES

To improve the efficiency of modal analysis for aeroengines of ensured computational accuracy, an improved hybrid interface substructure component modal synthesis (CMS) method is proposed to avoid massive calculation in traditional methods when the substructure is composited. The comprehensive model is further simplified and duel coordination conditions of displacement and force are introduced to ensure the accuracy of the calculation. The parametric model of the assembled structure of blades and disks is constructed to set up finite element models for each substructure, which are then synthesized using the coordination conditions of displacement and force to obtain modal frequencies. Compared with the overall structure finite element model, the computational time is reduced by 23.86%~35.74%, and the modal deviation is less than 0.57%, while the computational time was reduced by only 14.63%~29.20% and the modal deviation was less than 0.49% for traditional methods. Therefore, under the same working environment and to achieve the same level of computational accuracy, the proposed method is much more efficient than traditional methods, especially in the high order modal solution procedure. This study lays a solid foundation for further research on the dynamic responses of composite structures of the mistuned bladed disk assemblies for aeroengines.