Damping Ratio and Natural Frequency of Dynamic System in Milling
The problem of the machine tool stability in metalworking has existed since the first machine tool was created. Stability plays an important role in investigations dedicated to machining quality improvement, wear decrease, and, on the other hand, productivity increase. The identification of dynamic parameters such as modes, damping, and stiffness is a part of a stability problem. There are two groups of techniques to find the dynamic parameters: experimental modal analysis and operational modal analysis (OMA). In this study, OMA is used to identify the dynamic parameters of the system in milling. Responses (accelerations) are stored via three-axis accelerometer mounted on the spindle. Furthermore, power spectral density matrix of output responses is estimated. The estimation of natural frequencies and damping ratios is based on the analysis of a power spectral density matrix. A simulation model of milling is created, and some experimental tests are done to verify the suggested approach. The results are discussed as well.
KeywordsModal analysis Stability Milling
The work was supported by Ministry of Education and Science of the Russian Federation, contract № 02.G25.31.0148.
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