多点耦合系统中与耦合点有关的频响函数测量

Measurement of frequency response functions related to coupling points in multipoint coupled systems

在多点耦合系统的振动分析中经常需要测量与耦合点有关的频响函数。由于耦合点的不易测量的性质,此类频响函数的测量工作往往十分棘手。针对此类问题,进行了详细的分析和探讨,提出了完整的关于耦合点有关的频响函数测量的策略。依据激励点和响应点是否是耦合点将耦合点有关的频响函数分成三种类型:(Ⅰ)响应点是耦合点;(Ⅱ)激励点是耦合点;(Ⅲ)响应点和激励点都是耦合点。提出了第Ⅰ类和第Ⅱ类频响函数的测试策略,并基于机械系统中的诺顿定理将第Ⅲ类频响函数表示成第Ⅰ类和第Ⅱ类频响函数。数值模型和实验均验证了所提出的方法的正确性。

Frequency response functions(FRFs)related to coupling points usually need to be measured in the vibration analysis of multi-point coupled systems.Because of the inaccessible property of coupling points,the measurement of this kind of FRF is often very difficult.Aiming at this,detailed analyses and discussions were made in the paper.A complete strategy for measuring the FRFs related to coupling points was proposed.According to whether the excitation point and the response point are coupling points or not,the FRFs related to coupling points were divided into three types:(Ⅰ)The response point belongs to the coupling points.(Ⅱ)The excitation point belongs to the coupling points.(Ⅲ)Both the response point and the excitation point belong to the coupled points.First,the testing strategies of Class I FRFs and Class II FRFs were proposed.Then,according to the Norton Theorem in mechanical systems,it was proved that the Class III FRFs could be expressed as Class I and Class II FRFs.The correctness of the proposed method was verified by a numerical model and an experiment.