Siemens introduces its vibration damper for container cranes

Vibration of up to one metre occurs when the crane trolley moves depending on the type and size of the crane, and this can be further increased by high winds. The Siemens damper detects the vibration of the girder and algorithms use these values to precisely calculate how the linear motor has to be moved to neutralise the natural oscillation of the girder. Through intelligent acceleration and braking of the linear motor, the forces are directed into the girder with the result that vibration is reduced faster and more effectively than conventional methods.

Today’s gantry cranes are lighter and taller than their predecessors and they take up significantly less expensive quay space. In order to reduce vibration, cranes have to be ‘stiffer’ but it is no longer sufficient to simply use thicker metal sheets. When constructing a stiffer crane structure, for example, the crane span cross-sectional area and overhead clearance must often also be modified which is not easy to achieve.

Thus in order to reduce vibration, passive mass dampers are often used today. A weight of up to 60 tonnes is often suspended on a pendulum device with the vibration frequency set by the length of the pendulum. Energy is removed from the vibrating mass by a damper which stops this disturbing motion. Unfortunately, passive mass dampers of this type are extremely costly to integrate into the structure of the crane and the resulting damping effect is limited at best.