BALL-TYPE VIBRATION DAMPERS

System Dr. Trätner, German Patent DE-4109964

	maintenance-free
	full effect even in extreme weather
	precise adaptation of the damper frequency to the resonant frequency of the building/P>
	subsequent installation without problems/P>
	no wear and tear of mechanical parts
	adaptable at later moments
	small outside dimensions
	usable up to resonant frequencies of the building of < 2.5 Hz

THE PROBLEM

Tower-type buildings of a lean structure can be excited to build up horizontal oscillations by various exciting mechanism of the wind, as typically:

	gust-induced oscillations in the direction of the wind
	eddy-induced oscillations across the direction of the wind (-> Kármán vortex trail)
	galloping oscillations (classic galloping)
	interference galloping

The response of the system, which means. the amplitude of oscillations of the building, is essentially influenced by structural damping. If any systems provide of low damping only, such as steel smokestacks or columns in chemical plant construction, the most economical possibility for purposeful increase of damping will often be the use of a dynamic vibration damper.

left: Dying out process without vibration damper

right: Dying out process with ball-type vibration damper

HOW IT WORKS

The damping effect is reached on the ball-type vibration damper by the fact that a ball is rolling against the oscillation of the building in an oscillation rate which is displaced in phase, as soon as the acceleration of the building exerted by oscillations exceeds a specific value.

The ball diameter, the dome geometry and the oil filling level are coordinated to one another and to the building to optimise the damper effect.

Special calculation procedures have been developed and verified by multiple test series for determining the dimensions of the ball-type vibration damper.

FIELD OF APPLICATIONS

The ball-type vibration damper allows the economical construction of lean tower-like buildings if its damping-increasing effect is already considered during the planning phase.

Already existing buildings can be retrofitted without problems with the ball-type vibration damper can when major oscillations have occurred unexpectedly.

The ball-type vibration damper is used in plant engineering and construction if machinery with out-of-round run create horizontal resonance vibrations.

The ball-type vibration damper takes effect without maintenance and in an unlimited way under extremely adverse environmental conditions.

The ball-type vibration damper can be used up to resonant frequencies of the building of < 2.5Hz.

The installation of the ball-type vibration damper will effectively and permanently reduce vibrations. When the building construction is changed or if the theoretically determined resonant frequency deviates from the actually occurring resonant frequency, a simple exchange of the dome will adjust the damper in an optimal way.

On the building, you can arrange an unlimited number of ball-type vibration dampers one besides the other.

Above: Suggestion for installing the ball-Type vibration damper on a building.