基于预应力模态综合法的失谐叶片减振优化

Optimization of Vibration Reduction of Mistuned Blades Based on Pre-stressed Component Mode Synthesis Method

为了降低失谐导致的叶盘系统的振动局部化程度,以预应力模态综合法建立航空发动机压气机叶盘系统有限元缩减模型,计算了不同模态截断数下的固有频率,通过对比分析获得了在满足计算精度前提下的最小模态截断数,缩减了整体模型的自由度数.在该缩减模型的基础上提出一种叶片减振排布优化算法,该算法每次迭代计算时只生成叶片位置发生变化的子结构,而其他叶片的数据文件不动.结果表明,该优化算法兼顾了模型精度和计算速度,能大大降低叶片振动幅值,使叶盘系统振动局部化程度明显降低.

In order to reduce the level of the vibration localization of a mistuned bladed disk system by means of the pre-stressed component mode synthesis method,a reduced finite element model of the bladed disk system of an aeroengine compressor is constructed. Then,the natural frequencies with different mode truncation numbers are calculated,and through comparative analysis,the minimum mode truncation number satisfying the calculation precision is obtained. Moreover,the degree of freedom of the global model is reduced. Based on the reduced model,a blade vibration arrangement optimization algorithm is put forward,and at each iteration of the algorithm,only the substructure of a switching blade position is generated,while other blades data files remain unchanged. The results show that the constructed optimization algorithm takes into account both the model accuracy and the calculation speed,and it can greatly reduce the blade vibration amplitude and thus significantly reduce the vibration localization of the bladed disk system.