Experimental and Finite Element Analysis of Ball Screw Drive Vibrations

This study conveys the results of long stroke ball screw vibrations that were studied using a nonlinear finite element method. Because the nut in the experiment moved both forward and backward, a formulation that incorporated an updated Lagrangian method was employed to examine large displacement in the lateral directions. When the nut changed position, one of the screw segments became longer and its natural frequencies decreased, resulting in the formation of high-to-low frequency curves. However, when this occurred, the other screw segment became shorter and its natural frequencies increased, causing low-to-high frequency curves. A short-time Fourier transformation was used to determine the spectrograms for the forward and backward motions of the nut. Therefore, every frequency curve on the spectrograms that corresponded to one vibration mode formed a particular “ripple pattern.” Notable vibration signatures were verified in laboratory tests that measured the time-frequency spectrum of a stationary screw with a moving nut. The results of different nut speeds were also gathered and the ripple patterns were identified as being independent of nut motion.