Vibration of Automotive Bucks to 500 Hz and Higher 2001-01-0775
This paper describes a new process for vibrating large automotive bucks (body in white) to 500 Hz and higher. This process utilizes multiple electrodynamic shakers driving large magnesium mounting plates. The vertical axis utilizes three large head shakers driving a common magnesium plate 12 ft. long x 4 ft. wide. The shakers are dynamically matched, and the input a feedback signal is paralleled. This approach coupled with a closed loop digital vibration controller offers excellent dynamic uniformity to better than 500 Hz to the buck under test. The fore/aft and lateral utilize two shakers driving a common 12 ft. x 4 ft. magnesium slip plate. In the lateral, the shakers are side by side; and in the fore/aft, they are in a push-pull configuration. This approach offers control and spectrum tailoring to 500 Hz or higher. This method is dynamically superior over single shaker input and four poster shakers because the buck under test is seeing homogeneous vibration to 500 Hz. Dynamically it looks like two or three small plates rather than one large plate, without severe anti-resonances and resonances within the 500 Hz range.