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Research colloquium: Lecture by Dr.-Ing. Simon Klarmann from RWTH Aachen University on the perturbation-free coupling of volume and beam kinematics
We cordially invite you to the second lecture as part of the research colloquium for final theses and doctoral as well as habiliation candidates in 2026. This will take place on Monday (exceptionally!), 19.01.2026 at 16:30 in room 1120 Kurt-Wolters-Straße 3. We are pleased to have Dr.-Ing. Simon Klarmann (RWTH Aachen) as guest lecturer. The title of the lecture is:
"Between solid and beam kinematics: an approach for a perturbation-free transition"
Welook forward to seeing you there.
Abstract
In the context of the finite element method, beam elements are characterized in particular by their high efficiency in the modeling of slender structures. However, their disadvantages lie in the determination of effective cross-section values and the inability to model complex stress states in discontinuity regions.
Cross-section values can be determined using a solid model. In order to avoid obtaining results that are too stiff, it must be ensured that the cross-section can deform at the load application point. This includes deformation due to transverse contraction on the one hand, and warping due to shear or torsion on the other.
The discontinuity areas can be replaced by a solid model. Here, too, it is necessary to transfer the kinematics of a beam element to the solid element in order to connect it. In order to achieve a smooth transition, the cross-section at the transition must be able to deform accordingly.
A transition element is developed to solve both problems. For this purpose, the area between the beam and solid model is considered. The beam kinematics is enriched with an extended displacement field so that the cross-section can deform freely at the connection point of the beam. Furthermore, the weak form of the equilibrium in this area is considered, in which the required boundary terms are automatically included. These boundary terms provide information on how the extended displacement field is to be selected and which parts subsequently make an undesirable contribution to the virtual internal work. The resulting finite element formulation is capable of mapping the required transition without perturbration.