Fundamental Research

Keywords: multi-body systems, non-smooth dynamics, unilateral constraints, set-valued force laws, flexible multi-body systems, co-simulation

The main objective of the fundamental research at the Institute of Applied Mechanics are methods for the description of multi-body systems (MBS) with non-smooth dynamics. These are systems with closing contacts leading to jumps within the system velocities. Especially for industrial applications with many degrees of freedom and many contacts, efficient and robust methods are currently being developed. The granular media simulation of an hourglass can be seen as a benchmark-problem.

 

Besides the application of these methods to classical rigid multi-body systems there is a growing interest to extend them for the description of flexible multi-body systems with impacts and constraints. The crucial point is to derive models providing high efficiency and an accurate model description as well as versatile applicability . The classical distinction between finite elements (FE) and MBS is partly left aside to maintain – as far as possible – the advantages of FE-approaches within MBS. An example is given by the rocking rod, which classically is modeled rigid in non-smooth mechanic approaches.

Technical systems are usually composed of different assemblies with different leading physical phenomena but alternating interactions. So far – especially due to lower computational power – the subgroups like e.g. hydraulics and rigid-body dynamics of a chain drive were simulated separately.

To allow for the simulation of the complex over-all dynamics, a co-simulation is performed for the subgroups using own time-integrations and respecting the interactions.

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