Impedance Modeling for Machine Tool Applications - IMAC 18

P.Avitabile, F.Piergentili

Analytical models of automotive parts can be developed quickly and efficiently using finite element modeling techniques. In order to estimate dynamic characteristics of a part to be manufactured by a machining process, the dynamics of the machine itself can be important to the resulting frequencies of the system. Often, a finite element model of the machine is not available, and there is no easy way to include the dynamics of the machine in the model of the part. In these cases, incorrect boundary conditions are applied to the model of the part in order to estimate the natural frequencies of the part. These simple boundary conditions are truly not the proper conditions for the part to be analyzed but little else is available to approximate the system.

In this paper, an impedance modeling approach is used to model this situation. The dynamics of the interface connection between the machine and the part is used as a boundary condition for the finite element model of the part. The eigensolution of the model of the part alone is used along with measured impedances at the attachment points in the machine to form a system model.

This approach is used to identify the dynamic characteristics for several different parts to illustrate the approach. The results are compared to actual acquired data on the part in the machine.

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In the meantime, e-mail Peter_Avitabile@uml.edu for copy of paper