Research colloquium: Lecture by Sören Bieler from the University of Siegen on additively manufactured materials and structures under static and dynamic loads

As part of the research colloquium for final theses, doctoral and habilitation candidates, we cordially invite you to join us on Tuesday, April 28, 2026 at 4:30 pm in room 3516 (Mönchebergstr. 7). We are pleased to welcome Mr. Sören Bieler, M.Sc. from the Chair of Solid Mechanics at the University of Siegen as a guest speaker. The title of the lecture is:

"Additively manufactured materials and structures under static and dynamic loading"

Welook forward to seeing you there.

Abstract

The study of material behavior is a fundamental aspect of research in science and engineering as it has a direct impact on the design, performance and reliability of components in a wide range of applications. For most applications, quasi-static tests are performed according to the relevant standards to obtain material data. Since engineering structures such as buildings, bridges, etc. are considered to be unchanging over time, static material parameters are sufficient to calculate the stability of such structures. Under changing loading conditions, especially under dynamic loads with high strain rates, materials can exhibit significantly different mechanical material behavior compared to those observed under quasi-static conditions. This discrepancy poses a challenge for the accurate modeling and prediction of components in certain scenarios, such as car crashes, ballistic impacts or aerospace applications. Therefore, a deeper understanding of the mechanical behavior of materials under dynamic loading is essential for the development of more robust and efficient structures. In this context, experimental methods and numerical simulations play a crucial role in characterizing and predicting material behavior under such extreme conditions. The Split Hopkinson Pressure Bar is an important experimental apparatus for determining material behavior under high strain rates.

Additive manufacturing has developed steadily over the years and is now used not only for prototyping but also in series production. There are virtually no limits to the complexity of structures and components with additive manufacturing - it allows designs that would be difficult or impossible to realize with conventional manufacturing processes.

Energy absorption plays a central role in many application scenarios under quasi-static loads, but also in particular due to stresses caused by the impact of sudden forces. Among other things, materials that enable good energy absorption through appropriate deformation are suitable for this purpose. Lattice structures have damping properties with a relatively low material cost, which are also designed for multiple loads with a suitable choice of material and thus represent sustainable energy-absorbing structures. To examine energy-absorbing structures under quasi-static load, samples made of harder acrylic-like material are tested. Softer materials, such as TPU-like resin, are more suitable for impact loads. In contrast to hard, brittle polymers, these can still deform without failing even in the event of sudden impacts.

For both types of load, eight different types of structure are compared in terms of their specific energy absorption properties. Various parameters of the structures are taken into account, such as the number of struts within the structure or their surface values. When designing the individual structure types, the same relative densities can be realized for all structures in order to allow a suitable comparison between the individual geometries.

The aim of the investigation is to determine the significant differences between static and dynamic loading for additively manufactured samples made of different materials. Based on the results obtained, initial simulations for such test conditions can be created and compared with the experiments.