25 citations · 119 across the 12 of their papers we have counts for
12 papers
A new Surrogate Microstructure Generator for Porous Materials with Applications to the Buffer Layer of TRISO Nuclear Fuel Particles
Philipp Eisenhardt, Ustim Khristenko, Barbara Wohlmuth +1
We present a surrogate material model for generating microstructure samples reproducing the morphology of the real material. The generator is based on Gaussian random fields, with…
Risk-averse design of tall buildings for uncertain wind conditions
Anoop Kodakkal, Brendan Keith, Ustim Khristenko +4
Reducing the intensity of wind excitation via aerodynamic shape modification is a major strategy to mitigate the reaction forces on supertall buildings, reduce construction and mai…
Determining kernels in linear viscoelasticity
Barbara Kaltenbacher, Ustim Khristenko, Vanja Nikolić +2
In this work, we investigate the inverse problem of determining the kernel functions that best describe the mechanical behavior of a complex medium modeled by a general nonlocal vi…
Statistically equivalent surrogate material models and the impact of random imperfections on elasto-plastic response
Ustim Khristenko, Andrei Constantinescu, Patrick Le Tallec +1
Manufactured materials usually contain random imperfections due to the fabrication process, e.g., the 3D-printing, casting, etc. These imperfections affect significantly the effect…
Learning the structure of wind: A data-driven nonlocal turbulence model for the atmospheric boundary layer
Brendan Keith, Ustim Khristenko, Barbara Wohlmuth
We develop a novel data-driven approach to modeling the atmospheric boundary layer. This approach leads to a nonlocal, anisotropic synthetic turbulence model which we refer to as t…
Equivalence between a time-fractional and an integer-order gradient flow: The memory effect reflected in the energy
Marvin Fritz, Ustim Khristenko, Barbara Wohlmuth
Time-fractional partial differential equations are nonlocal in time and show an innate memory effect. In this work, we propose an augmented energy functional which includes the his…
Solving time-fractional differential equation via rational approximation
Ustim Khristenko, Barbara Wohlmuth
Fractional differential equations (FDEs) describe subdiffusion behavior of dynamical systems. Its non-local structure requires taking into account the whole evolution history durin…
Multidimensional coupling: A variationally consistent approach to fiber-reinforced materials
Ustim Khristenko, Stefan Schuß, Melanie Krüger +3
A novel mathematical model for fiber-reinforced materials is proposed. It is based on a 1-dimensional beam model for the thin fiber structures, a flexible and general 3-dimensional…
A fractional PDE model for turbulent velocity fields near solid walls
Brendan Keith, Ustim Khristenko, Barbara Wohlmuth
This paper presents a class of turbulence models written in terms of fractional partial differential equations (FPDEs) with stochastic loads. Every solution of these FPDE models is…
Frontiers in Mortar Methods for Isogeometric Analysis
Christian Hesch, Ustim Khristenko, Rolf Krause +4
Complex geometries as common in industrial applications consist of multiple patches, if spline based parametrizations are used. The requirements for the generation of analysis-suit…
A statistical framework for generating microstructures of two-phase random materials: application to fatigue analysis
Ustim Khristenko, Andrei Constantinescu, Patrick Le Tallec +2
Random microstructures of heterogeneous materials play a crucial role in the material macroscopic behavior and in predictions of its effective properties. A common approach to mode…
Analysis of boundary effects on PDE-based sampling of Whittle-Matérn random fields
Ustim Khristenko, Laura Scarabosio, Piotr Swierczynski +2
We consider the generation of samples of a mean-zero Gaussian random field with Matérn covariance function. Every sample requires the solution of a differential equation with Gauss…