用模态综合法分析发动机整机振动特性

本文试图把模态综合法与有限元素法相结合,对发动机转子——支承——机匣系统的整机振动特性进行分析。用状态空间广义模态综合法计算轴对称转子与机匣间的耦合振动,用复模态综合法计算非轴对称转子与机匣间的耦合振动。子结构分析采用有限元素法。转子采用具有粘性阻尼,考虑剪切变形的有限转子元素,用承受非轴对称载荷的截锥壳元素离散机匣。所编制的AROBEC程序可计算发动机整机系统的进动频率、临界转速、稳定性、不平衡响应及瞬态响应。目前该程序已实际应用于三种型号的发动机上,获得了满意效果。 

MODE SYNTHESIS ANALYSIS OF VIBRATION CHARACTERISTICS OF ENTIRE ENGINE

The mode synthesis is combined with the finite element method to analyze the vibration characteristics of the rotor-bearing-case system of an engine. The generalized state space mode synthesis method is adopted to calculate the coupling vibration characteristics between the axisymmetrical rotor and the case, and the complex mode synthesis method is applied to calculating those between the non-axisymmetrical rotor and the case. The finite element method is used to analyze the substructures.A program, named AROBEC, has been written for this purpose. It can calculatethe whirl frequence, critical speed, stability, unbalance response and transientresponse for engine system. The program includes preprocessing and postprocessingfunctions and provides conical shell finite elements and rotor finite elementswith viscous damping which take shear effect into account. The dynamic characteristics of three types of aeroengine have been analyzed with this program and the results are satisfactory.