Generalized Phenomenological Damping Model And Its Parameter Identification

In the study of structural dynamics,the test requires equipment with high precision and high economic cost.In contrast,establishing an accurate theoretical model is more economical and practical.At the same time,the identification of damping is an important aspect of damping theory research.The new damping theory is not only required to describe the damping characteristics in the mechanical system well,but also a relatively simple mathematical description and corresponding damping identification method is necessary,so that the damping parameters can be obtained by means of actual measurement.This paper studies the establishment of a frequency-dependent damping model and the identification of its modal parameters.The content is as follow.From the theoretical point of view,the low viscosity fluid damping,hysteretic damping,Coulomb dry friction damping and fractional derivative damping model of the single degree of freedom system are taken as examples to illustrate the characteristics of the existing damping model with frequency.A new generalized damped phenomenological model is constructed.Based on the least squares theory and MATLAB software as the platform,the program of point-by-point identification method and global identification method is compiled.A typical single-degree-offreedom spring oscillator system is taken as an example.The modal parameters of three single basis function forms and three kinds of combined basis function damping models are identified by the global identification method.The frequency-dependent damping characteristics of multi-degree-offreedom systems are simulated.Firstly,Taking multiple degrees of freedom as an example,the identified and modified damping model can predict the response of other points well,which verifies the rationality of the polynomial basis damping model.Finally,four identification methods are compared.The confirmatory experiments were carried out on the piezoelectric vibration-damping ring and viscoelastic composite beam,and the suitability of the polynomial-based damping model was verified.The results show that the polynomial based damping model proposed in this paper is more suitable than the traditional equivalent viscous damping model,and can more accurately describe the dynamic frequency-dependent damping characteristics of the actual engineering structure.