Bauhaus University, Weimar

About: Bauhaus University, Weimar is a education organization based out in Weimar, Thüringen, Germany. It is known for research contribution in the topics: Finite element method & Isogeometric analysis. The organization has 1421 authors who have published 2998 publications receiving 104454 citations. The organization is also known as: Bauhaus-Universität Weimar & Hochschule für Architektur und Bauwesen.

A constitutive-based element-by-element crack propagation algorithm with local mesh refinement

Abstract: In the context of multiple constitutive models, multiple finite element formulations and crack nucleation and propagation hypotheses, we propose a simple yet effective algorithm to initiate and propagate cracks in 2D models which is independent of the constitutive and element specific technology. Observed phenomena such as multiple crack growth and shielding emerge naturally, without specialized algorithms for calculating the crack growth direction. The algorithm consists of a sequence of mesh subdivision, mesh smoothing and element erosion steps. Element subdivision is based on the classical edge split operations using a given constitutive quantity (either damage or void fraction). Mesh smoothing makes use of edge contraction as function of a given constitutive quantity (such as void fraction or principal stress). To assess the robustness and accuracy of this algorithm, we use classical quasi-brittle benchmarks and ductile tests.

Tension-induced phase transition of single-layer molybdenum disulphide (MoS2) at low temperatures.

Abstract: We show that the hexagonal structure of single-layer molybdenum disulphide (MoS2), under uniaxial tension along a zigzag direction for large deformations, can transfer to a new quadrilateral structure by molecular dynamics (MD) simulations when the temperature is below 40 K. The new phase remains stable after unloading, even at room temperature. The Young's modulus of the new phase along the zigzag direction is about 2.5 times higher than that of normal MoS2. Checking against density functional theory calculations shows that the new phase is preserved and displays excellent electrical conductivity. Our results provide physical insights into the origins of the new phase transition of MoS2 at low temperatures.

The ESA retrieval model revisited

Abstract: Among the retrieval models that have been proposed in the last years, the ESA model of Gabrilovich and Markovitch received much attention. The authors report on a significant improvement in the retrieval performance, which is explained with the semantic concepts introduced by the document collection underlying ESA. Their explanation appears plausible but our analysis shows that the connections are more involved and that the "concept hypothesis" does not hold. In our contribution we analyze several properties that in fact affect the retrieval performance. Moreover, we introduce a formalization of ESA, which reveals its close connection to existing retrieval models.

On derivatives of spherical monogenics

Abstract: The main objective of this article is to consider complete orthonormal systems of monogenic polynomials together with their hypercomplex derivatives. Desired is that the derivatives of the basis polynomials are again basis functions from the original system. Based on this result, we prove an orthogonal decomposition of the space of square integrable monogenic functions with respect to the derivatives of arbitrary order. §Dedicated to Professor Guochun Wen on the occasion of his 75th birthday.