Research On Measurement And Application Of Material And Structural Damping Property

In recent years, as more and more problems of vibration and noise arise, damping material becomes the hotspot of material science, and material damping test is one of the key issues. Material damping test is important to many fields, including the establishing exact dynamics models of structure, analyzing on the stability of structure, predicting the response and investigating on new materials. The purpose of this paper is to develop a precise damping test software system.This paper chooses logarithmic attenuation method, Hilbert envelope method, half power bandwidth method and Circle-Fit method from numbers of damping identification methods, as the damping identification methods of the software system. Through selecting the appropriate frequency points Circle-Fit method can achieve the best results of the damping identification, which solves the problem that it can not be intervened manually during the process of damping identification, it makes full use of the experience of testers.With the development of computer and software technology, Virtual Instrument becomes the development direction in testing areas. This paper develops a test software system by LabVIEW8.6 software. This software system includes parameter setting, data acquisition, data processing, damping identification and results storage modules. Chirp Z Transform is used to local frequency refining for improving the identification accuracy in frequency domain. Multi-degree of freedom system is decomposed into single degree of freedom system by band-pass filtering, and then applies the logarithmic decrement method and the Hilbert envelope method to identify damping.In this paper, both simulation and experimental measurement is used to verify the software reliability. Evaluating damping identification accuracy of four methods based on the same simulation data. This paper measures the samples with same material but different shapes, and then compares with the recognition results and the ANSYS results to verify the accuracy of modal frequency identification. Samples of different materials are been measured, giving the method of damping evaluation of different materials by the software system.