Vibration damping of elastically mounted windows for noise reduction in construction vehicles

Operator cabins of construction vehicles are usually enclosed in order to protect the operator from weather. In contrast to cars, aerodynamic resistance plays a subordinate role in construction vehicles due to the low driving speed. Therefore, and for a good all-round view, these vehicles have large and often flat window panes. Vibrations, e.g. of the drivetrain or caused by rolling over coarse tire treads, are transferred via the vehicle-structure to the operator cabin and excite its not sufficiently decoupled surfaces to vibrate. The window panes are usually mounted in viscoelastic rubber seals. Due to the seal, the bearing and large surfaces, the windows tend to vibrate when they are appropriately excited. Vibrating windows create unwanted noise inside the operator cabin, which can be harmful to health. In this paper we report on a method for reducing the vibration of the window pane of a construction vehicle. By using several window-mounted inertial shakers as tuned mass absorbers in combination with an error-microphone and static control, the window pane is being chilled and, as a result, noise is reduced in the interior of the cabin. This solution is able to counteract acoustic modes in the lower frequency range below 100 Hz.