... is composed of several steps mainly including the shock pressure prediction, the modal analysis, and the forming process calculation. System critical damping is introduced to prevent unnecessary long post-shock residual oscillations and to greatly decrease the solution time for simulation. The bending...

... is transformed into the principle modal directions of the rotating tool. The process damping is modeled as a linear function of vibration velocity. The dynamics of the milling system is modeled by a time delay matrix differential equation with time varying directional factors and speed dependent elements...

...E. Budak; L. T. Tunc Although process damping has a strong effect on cutting dynamics and stability, it has been mostly ignored in chatter analysis as there is no practical model for estimation of the damping coefficient and very limited data are available. This is mainly because of the fact...

... considers the effect of tool vibrations at the present and previous spindle revolutions on the chip area, chord length, and force directions and is solved using Nyquist stability criterion. The penetration of worn tool flank into the finish surface is considered as a source of process damping. The effects...

...C. Y. Huang; J. J. Junz Wang This paper extends analytical modeling of the milling process to include process damping effects. Two cutting mechanisms (shearing and plowing mechanisms) and two process damping effects (directional and magnitude effects) are included. The directional effect is related...

... bearing is employed both to excite the system and to increase the tool’s damping. The inherent time delay of the cutting process is “removed” in identification by limiting the observation period to less than one revolution period of the workpiece. The coefficients of several cutting tests were identified...

... operation has averaged the magnitude of these oscillations within each frame. The number of self-excited oscillations per tool revolution is given by the index number k p , max , so that the damping ratio ζ can be estimated by 6 ζ = δ R , k p max ∕ ( 2 k p , max...

... added lobes. The stability limit solution is first derived for zero damping where a final closed-form symbolic result can be realized up to second order. The un-damped solution provides a mathematical description of the added lobes’ locations along the speed axis, an added-lobe numbering convention...

... periodicity and damping. The added-lobes are shown to exist with a zero overlap factor (i.e., no regeneration) and to scale in magnitude (limiting width of cut) relative to overlap factor. Furthermore, the added lobes are shown to exist for multi-tooth machining even when there are no periods of full cutter...

... representative parameter, the “Green’s Function (GF).” This reflects the dynamic behavior of the tool prior to failure and, may provide a comprehensive and accurate measure of the damping variation of the cutting process subsystem at different forms of tool’s edge wear. As wear enters the high rate region...

...B. Fang; R. E. DeVor; S. G. Kapoor In this paper, a dynamic model that considers the vibrations of both the workpiece and fixture elements in order to accurately predict the friction damping over a wide range of clamping forces has been developed. The model is established based on the theory...

... characteristics have been compared to those obtained from the experiments and are found to be in good agreement. It was found that frictional sliding contact at the workpiece-fixture interfaces provides damping to the system and that the nature of this contact and level of damping are highly dependent on contact...