Universität Stuttgart

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Author: search.filters.author.Fischer, ChristianAuthor: search.filters.author.Eberhard, Peter

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    Experimental investigations on impact transmission through a plate
    (2013) Fischer, Christian; Eberhard, Peter
    The concept of an impact actuated shift valve is presented. This valve concept can be actuated by different kinds of actuators, such as piezo stack actuators. A simplified model for the investigation of the impact process is created. The model consists of a plate, two spheres and a fluid-filled tank. Experiments are presented with and without fluids and different plates. The results are compared to simulations.
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    Investigation and design of an impact actuated micro shift valve
    (2013) Fischer, Christian; Fritz, Karl-Peter; Eberhard, Peter; Kück, Heinz
    New concepts for an impact actuated micro shift valve are presented which are useful e.g. as im plant for the hydrocephalus disease. Such an implant must fulfil requirements, such as using biocompatible materials, a separation of the actuator from the fluid, MRT safety and low energy consumption in order to allow a battery powered system. The concepts are based on impacts that transmit an impulse into the interior of the valve through the casing, switching the valve. In order to predict the energy transmitted into the valve, an elastic multibody model is created, verified with full finite element simulations and experiments on scaled-up models. Using this model, the most important effects and parameters are discussed. Also, fluid effects are included into the elastic multibody model for a qualitative assessment of its influence on the efficiency. The simulations are compared to experiments performed with a scaled model for two different cases. Two designs of a shift valve based on impact actuation are built as prototypes and tested.
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    Simulation of a micro shift valve with impact actuation
    (2011) Eberhard, Peter; Fischer, Christian
    A new concept of an impact actuated micro shift valve is presented. The impacts are transmitted to the interior of the valve through the casing. In order to predict the energy transmitted into the valve, the most important effects are discussed and two elastic multibody models using the Hertzian contact law are introduced and compared to a full finite element simulation. A simpler model with one degree of freedom for an elastic plate as transmission element proves to be too crude. But a more sophisticated model with axisymmetric finite elements for the plate shows good agreement. The simulations are compared to experiments performed with a scaled model for two different cases. The experiments show that so far neglected effects like plastic deformation occur and must be considered in the simulation if accurate predictions are required.