基于模态叠加法的航空发动机轮盘振动特性研究

以某型航空发动机轮盘为研究对象,分别通过数值模拟和试验测试获得结构特定振型下的模态参数;提出采用模态置信度开展模态振型的相关度评价;基于模态叠加法开展轮盘结构谐响应分析,并通过理论推导和数值仿真开展结构阻尼和激励量值对振动响应的影响规律研究。结果表明,在轮盘结构三节径振型处,共振频率计算结果与测试结果相差1.7%,验证了模态测试的正确性。模态振型置信度为0.999,说明模态测试与仿真结果吻合较好。通过谐响应分析得到轮盘最危险点的幅频曲线,并基于数值仿真验证了轮盘结构振动响应幅值与模态阻尼呈反比、与激励量值呈正比的理论推导的正确性。

Research of vibration characteristics of aero-engine disk based on modal superposition method

By taking a certain type of aero-engine disk as the research object,modal parameters of the specific modes is acquired by simulation and experiment.The Modal Assurance Criterion(MAC)verification is proposed to quantitatively describe the modal shape correlation between simulation and experiment.Then,the harmonic response analysis of the disk is developed based on modal superposition method,and influence of modal damping and excitation value on vibration response is further presented through theoretical derivation and simulation.Results show that the resonance frequency difference of the 3 th nodal diameter is 1.7%and the MAC is 0.999 between simulation and experiment,which illustrates the good consistency and meets the requirement of engineering test.Finally,the amplitude-frequency curve of the most dangerous position is established by the harmonic response analysis,and theoretical derivation that the vibration response amplitude of the disk is inversely proportional to the modal damping and directly proportional to the excitation value is verified by simulation,which can provide reference for the dynamic strength design and vibration testing of disks.