Damping Systems

About Damping

The Energy Absorbing System by DAMP

The specific design of the hinge guarantees that only compression load is applied on the rubber bushes (damping element). Thus the best working conditions can be guaranteed for the rubber element.
The elastomers used in the hinges of the arms of the spacer damper are capable of withstanding conductor temperatures of -30°C to 100°C without permanent loss of essential properties. They are designed as to provide effective damping in a temperature range of -5°C to 100°C.
The elastomers have an adequate resistance to the effect of ozone, ultraviolet radiation and other atmospheric contaminants (salt fog, industrial pollution etc.) over the entire temperature range and throughout the life cycle of the line.
They will withstand continuous hard working energy because they can absorb dynamic loads with little functional impairment. The energy absorbing assembly is electrically conductive.
Articulation of the spacer damper is designed as to provide the maximum damping effect under all the conditions of conductor vibration. The design is based on the following points:

• It is important to formulate an elastomer compound that is resistant to large hysteris losses, is sufficiently stiff and has the required mechanical performance and to define an articulation geometry enabling the elastomer to work under conditions of peak efficiency, i.e. mainly in compression: Elastomers working in tension can suffer severe cracking and are more resistant to ozone attacks.
• Torsional locks serve to protect the elastomers from excessive stress due to short circuits without limiting the articulation movements necessary for sustaining the maximum sub-conductor oscillations.
• Any displacement of the elastomer bushes in the housing should be avoided.
• The ratio between force and displacement of a damping articulation is characterized by a hysteresis loop whose area represents the energy dissipated in one rotation cycle in engineering units.
• In order to control aeolian vibrations, the articulation must be capable of producing a suitable damping effect for small rotations. Figure 1 shows the hysteresis loop of two different articulations.
• Loop A is produced by an articulation with the correct stiffness while Loop B refers to an articulation using soft elastomer bushes. Since the energy dissipated in one rotational cycle is represented by the area of the hysteresis loop, it can be seen that the efficiency of the articulation using soft elastomers is very poor.
• Similar deliberations can be made regarding sub-span oscillations (see Figure 2). In general, the fact that arm rotations produce narrow hysteresis loops or no loops at all means that the articulations are merely elastic and the spacer does not have damping capacity, i.e. it is a flexible or articulated spacer.