Reversible elastic structures

Structure-structure interaction

The example shown may serve to demonstrate the significant effects on the structure-structure interaction.

A cluster of DEM particles falls, starting from rest, under the influence of gravitation on a thin membrane made from hyper-elastic material. The membrane is fixed at its outer edge. The membrane consists of a non-damped material. The final state of rest remaining in the membrane is a result due to the friction between the particles.

Copyright: Fraunhofer SCAI / Fraunhofer IWM

It is a co-simulation between SimPARTIX® and Abaqus/Explicit

In this application the wall is modeled on that of the DEM codes side via a particle collective, which can be moved only as a result of the coupling. In fact, each of the "wall particles" represents a node in the finite element mesh of the structural code.

The DEM repulsion dominates the time increment substantially. An elastic collision is broken in about 50 time steps during the contact time.

The following animation shows the time course of nodal forces acting on the elastic membrane over a period of about 50 microns and 420 simulated time steps.

Copyright: Fraunhofer SCAI / Fraunhofer IWM

The structure appears to be in a steady state, although the forces vary greatly. The effect appears due to the small time increment and the time interval, and illustrates the different time scales on which one has to run the particle and structural dynamics simulations.