Modelling and simulation of the meso- and macro-mechanical properties of hollow sphere structures

Das mechanische Verhalten von Hohlkugelstrukturen wurde modelliert und anhand einfacher Packungen numerisch simuliert. Die erforderlichen Stoffdaten wurden dabei aus den Eigenschaften gegossener Folien ermittelt.

The mechanical properties of hollow sphere structures are investigated both experimentally and theoretically within a joint project of the Structure and Material Mechanics Research Dresden Inc., (SWM), and the Fraunhofer Institute for Manufacturing and Advanced Materials Dresden (IFAM). The main goals of the project are the improvement of the production processes for stainless steel hollow sphere structures (IFAM) and the numerical simulation of their mechanical behavior (SWM). This paper presents first results obtained in the mechanical modeling and simulation work package dealt with by SWM. Based on experimentally determined cell wall properties, elastic and non-linear calculations of shell models were carried out. Using a unit cell model and symmetry conditions, it is possible to obtain limited information on the behavior of ordered hollow sphere structures in compression. In order to simulate randomly packed structures, virtual hollow sphere structures were generated by using tomographical data obtained from real structures. It will be shown that the size of the contact areas of the spheres as well as the normals on these contact areas can be derived readily from the tomographical data.