110 citations · 751 across the 32 of their papers we have counts for
32 papers
Generalized eigenvalue stabilization for immersed explicit dynamics
Tim Bürchner, Lars Radtke, Sascha Eisenträger +4
Explicit time integration for immersed finite element discretizations severely suffers from the influence of poorly cut elements. In this contribution, we propose a generalized eig…
On the efficiency of explicit and semi-explicit immersed boundary finite element methods for wave propagation problems
Tim Bürchner, Lars Radtke, Philipp Kopp +3
Immersed boundary methods have attracted substantial interest in the last decades due to their potential for computations involving complex geometries. Often these cannot be effici…
Quantitative Comparison of the Total Focusing Method, Reverse Time Migration, and Full Waveform Inversion for Ultrasonic Imaging
Tim Bürchner, Simon Schmid, Lukas Bergbreiter +3
Phased array ultrasound is a widely used technique in non-destructive testing. Using piezoelectric elements as both sources and receivers provides a significant gain in information…
Implicit-Explicit Time Integration for the Immersed Wave Equation
Christian Faßbender, Tim Bürchner, Philipp Kopp +2
Immersed boundary methods simplify mesh generation by embedding the domain of interest into an extended domain that is easy to mesh, introducing the challenge of dealing with cells…
From ductile damage to unilateral contact via point-wise implicit discontinuity at the infinitesimal element level
Alireza Daneshyar, Leon Herrmann, Stefan Kollmannsberger
Ductile damage models and cohesive laws incorporate the material plasticity entailing the growth of irrecoverable deformations even after complete failure. This unrealistic growth…
Isogeometric Multi-Resolution Full Waveform Inversion based on the Finite Cell Method
Tim Bürchner, Philipp Kopp, Stefan Kollmannsberger +1
Full waveform inversion (FWI) is an iterative identification process that serves to minimize the misfit of model-based simulated and experimentally measured wave field data, with t…
Transfer Learning Enhanced Full Waveform Inversion
Stefan Kollmannsberger, Divya Singh, Leon Herrmann
We propose a way to favorably employ neural networks in the field of non-destructive testing using Full Waveform Inversion (FWI). The presented methodology discretizes the unknown…
On the Use of Neural Networks for Full Waveform Inversion
Leon Herrmann, Tim Bürchner, Felix Dietrich +1
Neural networks have recently gained attention in solving inverse problems. One prominent methodology are Physics-Informed Neural Networks (PINNs) which can solve both forward and…
Two-scale analysis and design of spaceframes with complex additive manufactured nodes
Oguz Oztoprak, Alexander Paolini, Pierluigi D'Acunto +2
The advancements in additive manufacturing (AM) technology have allowed for the production of geometrically complex parts with customizable designs. This versatility benefits large…
Immersed boundary parametrizations for full waveform inversion
Tim Bürchner, Philipp Kopp, Stefan Kollmannsberger +1
Full Waveform Inversion (FWI) is a successful and well-established inverse method for reconstructing material models from measured wave signals. In the field of seismic exploration…
Predicting Fracture in the Proximal Humerus using Phase Field Models
L. Hug, G. Dahan, S. Kollmannsberger +2
Proximal humerus impacted fractures are of clinical concern in the elderly population. Prediction of such fractures by CT-based finite element methods encounters several major obst…
Space-time hp finite elements for heat evolution in laser-based additive manufacturing
Philipp Kopp, Victor Calo, Ernst Rank +1
The direct numerical simulation of metal additive manufacturing processes such as laser powder bed fusion is challenging due to the vast differences in spatial and temporal scales.…
Enforcing essential boundary conditions on domains defined by point clouds
Frank Hartmann, Stefan Kollmannsberger
This paper develops and investigates a new method for the application of Dirichlet boundary conditions for computational models defined by point clouds. Point cloud models often st…
The Finite Cell Method with Least Squares Stabilized Nitsche Boundary Conditions
Karl Larsson, Stefan Kollmannsberger, Ernst Rank +1
We apply the recently developed least squares stabilized symmetric Nitsche method for enforcement of Dirichlet boundary conditions to the finite cell method. The least squares stab…
Quantitative reconstruction of defects in multi-layered bonded composites using fully convolutional network-based ultrasonic inversion
Jing Rao, Fangshu Yang, Huadong Mo +2
Ultrasonic methods have great potential applications to detect and characterize defects in multi-layered bonded composites. However, it remains challenging to quantitatively recons…
Efficient multi-level hp-finite elements in arbitrary dimensions
Philipp Kopp, Ernst Rank, Victor M. Calo +1
We present an efficient algorithmic framework for constructing multi-level hp-bases that uses a data-oriented approach that easily extends to any number of dimensions and provides…
Uncertainty quantification of microstructure variability and mechanical behaviour of additively manufactured lattice structures
Nina Korshunova, Iason Papaioannou, Stefan Kollmannsberger +2
Process-induced defects are the leading cause of discrepancies between as-designed and as-manufactured additive manufacturing (AM) product behavior. Especially for metal lattices,…
Bending behavior of additively manufactured lattice structures: numerical characterization and experimental validation
Nina Korshunova, Gianluca Alaimo, Seyyed Bahram Hosseini +6
Selective Laser Melting (SLM) technology has undergone significant development in the past years providing unique flexibility for the fabrication of complex metamaterials such as o…
Image-based numerical characterization and experimental validation of tensile behavior of octet-truss lattice structures
Nina Korshunova, Gianluca Alaimo, Seyyed Bahram Hosseini +6
The production of lightweight metal lattice structures has received much attention due to the recent developments in additive manufacturing (AM). The design flexibility comes, howe…
Hierarchical multigrid approaches for the finite cell method on uniform and multi-level hp-refined grids
John Jomo, Oguz Oztoprak, Frits de Prenter +3
This contribution presents a hierarchical multigrid approach for the solution of large-scale finite cell problems on both uniform grids and multi-level hp-discretizations. The prop…
Finite Cell Method for functionally graded materials based on V-models and homogenized microstructures
Benjamin Wassermann, Nina Korshunova, Stefan Kollmannsberger +2
This paper proposes an extension of the finite cell method (FCM) to V-rep models, a novel geometric framework for volumetric representations. This combination of an embedded domain…
Image-based material characterization of complex microarchitectured additively manufactured structures
N. Korshunova, J. Jomo, G. Lékó +3
Significant developments in the field of additive manufacturing (AM) allowed the fabrication of complex microarchitectured components with varying porosity across different scales.…
A 3D benchmark problem for crack propagation in brittle fracture
Lisa Hug, Stefan Kollmannsberger, Zohar Yosibash +1
We propose a full 3D benchmark problem for brittle fracture based on experiments as well as a validation in the context of phase-field models. The example consists of a series of f…
Direct structural analysis of domains defined by point clouds
László Kudela, Stefan Kollmannsberger, Umut Almac +1
This contribution presents a method that aims at the numerical analysis of solids represented by oriented point clouds. The proposed approach is based on the Finite Cell Method, a…