Active nonlinear energy sinks for applications in civil engineering

Nonlinear energy sinks (NES) are employed for vibration damping. As an additive system, they can be easily integrated into a base structure.

Energy sinks can consist of different elements. However, low damping, a small damper mass—small in comparison to the mass of the base structure—and a nonlinear elastic component are essential. The nonlinearity of the elastic component can be generated, for example, by a contact condition or large deflection.

In vibration damping applications, nonlinear energy sinks offer advantages over classic linear tuned mass dampers (LTMDs). They are effective over a wider range of frequencies and they do not alter the dynamics of the system outside this effective range.

The complex mechanisms of nonlinear energy sinks have been well researched over the past two decades [1]. Analytical and numerical investigations have focused on describing the conditions required for nonlinear energy transfer from the base structure to the energy sink. In the case of periodic excitation, it is also important that this transfer is maintained.

Practical investigations—both experimental and in simulations—show that nonlinear energy sinks can be successfully used to dampen earthquake or blast loads in buildings [2, 3].

However, a particular challenge is that the effectiveness depends heavily on the intensity of the excitation. This dependency can limit possible applications in practice.

The aim of the project is to develop models for active nonlinear energy sinks that operate reliable over a wide range of excitation intensities and frequencies. The models include active, controllable components that increase the robustness and effectiveness of the systems by adjusting structural parameters.

The research work is based on theoretical analyses and numerical simulations.

The focus is on applications in civil engineering. The base structures investigated therefore represent building types such as high-rise buildings and bridges. The loads applied include typical external influences like earthquakes, wind loads, and dynamic traffic loads such as train traffic.