The Damping Effect of Joints Formed from Machined Surfaces — The State of the Art

Summary

It is well established that one of the great obstacles to a complete understanding of the static and dynamic behaviour of machine tool structures is the inability to take the effects of the joints fully into account. The relevant properties of the joints are the static stiffness and the damping capacity. In both cases the aim must be not only to understand fully the parameters which affect these properties so that they may be optimised but also to be able to calculate and predict actual values. This latter requirement is necessary before any complete computer simulation of a machine tool structure can be made.

Many attempts have been made to investigate the damping effects but to a large extent have lacked direction and very little other than empirical observation has been achieved. However, the combination of results from these various investigations does lead to an indication of the true mechanism. This paper summarises the results of these investigations and draws the conclusion that the mechanism of damping is not merely due to friction as is often assumed but is a complex one of micro and macro friction and cyclic plastic deformation of the asperities.