Transferproject T5

Strut with an integrated hydraulic vibration absorber

During the second funding period in subproject C4 the so-called Fluid Dynamic Vibration Absorber (FDA) was developed. The inertial mass of the FDA is greater than the gravitational mass due to hydraulic transmission. The transfer project T5 has two goals: firstly, to validate the FDA within the SFB-Demonstrator including the function, the tuning and the axiomatic model of the FDA. Secondly, to design a prototype together with ZF Friedrichshafen AG to integrate the FDA in a strut for vehicle integration.

Furthermore, the methodology of the self-adaptation in order to achieve resilience is examined. Consequently, adjusting valves are used in the FDA.

Principle of the FDA

By the use of the FDA, vibrations in a defined frequency band of a basic system can be reduced. Energy is redirected into the structure extension. The FDA (Fig. 1) consists of a spring 1 which connects the structure to be soothed 2 to a piston 3. When the piston is immersed, liquid is displaced into a second cylinder chamber 4 via a channel surface 5. The hydraulic transmission between piston and channel area is α:=A/a>1. The light weight principle of the FDA is illustrated by the ratio of heavy mass to the acting inert mass, which is of the order of magnitude of α^(-2) at a small piston mass m_k.

Simulation results from a quarter-vehicle model show that the driving safety of a suspension as a measure of the wheel load fluctuation can be increased by 11 % by integration of the FDA. To confirm this result, the axiomatic model is validated with the functional prototype (Fig. 2) on the servo-hydraulic testing machine.

Prototype in the servo-hydraulic testing machine
  Name Contact
Prof. Dr.-Ing. Peter Pelz
+49 6151 16-27100
Scientific Staff
Nicolas Brötz M.Sc.
+49 6151 16-27126