Research On Measurement Of Structure Damping Property Based On Virtual Instrument

With the machinery and equipment getting more powerful and more compact structure, the problem of noise and vibration is getting worse. Quantitative study of structural damping characteristics of mechanical equipment can provide very important design parameters for the design and production. Therefore, damping test and measurement of structure is a significant part of vibration and noise reduction. This topic is to develop a test and measurement system for the damping characteristics through the virtual instrument.After the calculation of frequency response function of vibration system, the system's unit impulse response of free decay can be obtained through the inverse FFT , using 1 / 3 octave filter to attenuate the signal for the band division, and then use the exponential fitting and linear fitting of vibration level to calculate loss factor in a specific band.With exponential amplitude fitting and linear energy fitting methods, based on the virtual instrument platform Labview of NI modularly develops a measurement system of loss factor, this system demonstrates real-time decay curves of different frequency bands, and users can choose the best fitting time to achieve the best results. This makes full use of the experience of the testers, resolves the problem that it can not intervene in the damping identification process with artificial intelligence. Through data validation by simulation, the damping measurement system can accurately calculate loss factor, and measurement results are reliable.A measurement platform of damping tests was designed and built, and some simple structure's damping characteristics was measured. Loss factors in 1 / 3 octave bands and modal frequency are calculated through the methods above. It is showed that how to use the measurement system and test the damping characteristic for further damping identification with this system.