This paper presents a real-time dynamic substructuring (RTDS) test program carried out on bridge structures equipped with two innovative viscous seismic protective devices: a seismic damping unit and a shock transmission unit.
However, this technique works only when the damping unit is not used, because it relies on an evaluation of small shifts of the natural frequency f0.
We found τ= 6.0±0.5) s without eddy current damping, and τ′=(0.3±0.1) s with the damping unit.
Figure 3b shows the essential parts of the eddy current damping unit.
For the calibration, the damping unit is removed, because the cantilever is bent almost 3 mm due to the weight of the mirrors and the target holder; the target holder would rest on the damping unit.
In contrast, the amplitudes at other frequencies persist; the remaining frequencies can be understood as the complicated modes of the entire setup that result not only in vibrations of the lenses but also of the damping unit, which are unintentionally transmitted to the target via the eddy currents.
The oscillator model is assumed to be consisting of two nodal masses that are connected by means of a spring-damper unit.
The composite cells are intended for a possible use as structural damping units to be located in maximum nodal strain positions corresponding to specific wind turbine blade modes.
These aspects, combined with intelligent controls, active damping units, and new materials, will contribute to the quest for a reduced levelized cost of energy.
The novelty of the results presented here, is that the use of a hybrid numerical experimental testing technique called real-time dynamic substructuring, allowed a numerical model of the rotor to be combined with the physical testing of a flight certified lag damper unit.
The weight of the car is then supported by a diagonal "pull rod", which is attached to the spring and damper unit.
