基于Hammerstein模型的柴油机隔振非线性系统振动分析

针对柴油机隔振非线性系统，提出基于Hammerstein模型的曲线拟合方法，研究系统非线性对其振动特性的影响，并在模态试验基础上获得线性结构动力特征。基于Hammerstein模型建立广义频响函数，考虑基频谐振广义频响函数对基频响应的作用，提取系统（1阶广义）频响函数。曲线拟合技术对（1阶广义）频响函数进行频域估计，识别出线性结构动力特征。模态参数辨识试验结果表明，提出的方法对于柴油机隔振非线性系统的线性模态参数估计是合理、有效的。基于Hammerstein模型的曲线拟合，能够消除系统非线性对振动特性影响，并能够获得系统的线性结构动力特征。

Vibration Analysis of Diesel Vibration Isolation Nonlinearity-system Based on Hammerstein Model

For diesel vibration isolation nonlinear system, curve fitting method based on Hammerstein model is proposed, which can discuss how nonlinearity affects features of vibration system and can obtain linear structural dynamical features by implementing mode test. Generalized Frequency Response Functions (GFRFs) is established based on Hammerstein model, and (the 1st generalized) FRF of the system is extracted when considering fundamental frequency harmonic GFRFs’ impact on fundamental frequency response. (The 1st generalized) FRF is estimated by employing curve fitting method in frequency-domain, and linear structural dynamical feature is identified. The experimental result of mode parameters identification showed that the proposed method was valid and feasible to estimate linear mode parameters of diesel vibration isolation nonlinear system. When carrying out curve fitting based on Hammerstein model, one can eliminate nonlinearity effects on features of vibration system, and can obtain linear structural dynamical feature of nonlinear system.