Search Results - "Unger, Jörg F"

Modelling of cohesive crack growth in concrete structures with the extended finite element method by Unger, Jörg F., Eckardt, Stefan, Könke, Carsten

“…In this paper, the extended finite element method (XFEM) is used for a discrete crack simulation of concrete using an adaptive crack growth algorithm…”
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A Three-Phase Transport Model for High-Temperature Concrete Simulations Validated with X-ray CT Data by Pohl, Christoph, Šmilauer, Vít, Unger, Jörg F.

“…Concrete exposure to high temperatures induces thermo-hygral phenomena, causing water phase changes, buildup of pore pressure and vulnerability to spalling. In…”
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From concrete mixture to structural design—a holistic optimization procedure in the presence of uncertainties by Agrawal, Atul, Tamsen, Erik, Unger, Jörg F., Koutsourelakis, Phaedon-Stelios

“…Abstract We propose a systematic design approach for the precast concrete industry to promote sustainable construction practices. By employing a holistic…”
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Efficient structural reliability analysis by using a PGD model in an adaptive importance sampling schema by Robens-Radermacher, Annika, Unger, Jörg F.

“…One of the most important goals in civil engineering is to guarantee the safety of the construction. Standards prescribe a required failure probability in the…”
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PGD in thermal transient problems with a moving heat source: A sensitivity study on factors affecting accuracy and efficiency by Strobl, Dominic, Unger, Jörg F., Ghnatios, Chady, Robens‐Radermacher, Annika

“…Thermal transient problems, essential for modeling applications like welding and additive metal manufacturing, are characterized by a dynamic evolution of…”
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Coupling of scales in a multiscale simulation using neural networks by Unger, Jörg F., Könke, Carsten

“…Multiscale approaches require the coupling of models on different spatial scales. In this paper, a coupling using neural networks is proposed. Based on a set…”
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System Identification and Damage Detection of a Prestressed Concrete Beam by Unger, Jörg F, Teughels, Anne, De Roeck, Guido

“…In the domain of civil engineering it is often necessary to monitor constructions such as buildings or bridges to maintain safety conditions. Nondestructive…”
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Multiscale Modeling of Concrete by Unger, Jörg F, Eckardt, Stefan

“…In this paper, a mesoscale model of concrete is presented, which considers particles, matrix material and the interfacial transition zone (ITZ) as separate…”
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Damage Detection of a Prestressed Concrete Beam Using Modal Strains by Unger, Jörg F, Teughels, Anne, De Roeck, Guido

“…Different methods are proposed in literature using experimental modal information to detect possible damage. In this paper a finite-element (FE) model updating…”
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Efficient higher-order cycle jump integration of a continuum fatigue damage model by Titscher, Thomas, Unger, Jörg F.

“…•Formulation of fatigue as ODE of the history variables.•Adaptive Runge–Kutta schemes accelerate fatigue simulations by factor of 50–100.•Novel fatigue model…”
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Explicit dynamics in impact simulation using a NURBS contact interface by Otto, Peter, De Lorenzis, Laura, Unger, Jörg F.

“…Summary In this paper, the impact problem and the subsequent wave propagation are considered. For the contact discretization an intermediate non‐uniform…”
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Implicit–Explicit Integration of Gradient-Enhanced Damage Models by Titscher, Thomas, Oliver, Javier, Unger, Jörg F

“…AbstractQuasi-brittle materials exhibit strain softening. Their modeling requires regularized constitutive formulations to avoid instabilities on the material…”
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Multiscale modeling of linear elastic heterogeneous structures via localized model order reduction by Diercks, Philipp, Veroy, Karen, Robens‐Radermacher, Annika, Unger, Jörg F.

“…In this article, a methodology for fine scale modeling of large scale linear elastic structures is proposed, which combines the variational multiscale method,…”
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Coupling a NURBS contact interface with a higher order finite element discretization for contact problems using the mortar method by Otto, Peter, De Lorenzis, Laura, Unger, Jörg F.

“…In this paper, a contact problem between two bodies, discretized by finite elements, is solved by adding an auxiliary NURBS layer between the bodies. The…”
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Constitutive modeling of creep-fatigue interaction for normal strength concrete under compression by Kindrachuk, Vitaliy M., Thiele, Marc, Unger, Jörg F.

“…•A constitutive damage model for concrete under compressive fatigue is presented.•The model is based on a viscous formulation which induces damage.•Fatigue and…”
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Bayesian inference for random field parameters with a goal-oriented quality control of the PGD forward model’s accuracy by Coelho Lima, Isabela, Robens-Radermacher, Annika, Titscher, Thomas, Kadoke, Daniel, Koutsourelakis, Phaedon-Stelios, Unger, Jörg F.

“…Numerical models built as virtual-twins of a real structure (digital-twins) are considered the future of monitoring systems. Their setup requires the…”
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Efficient bead-on-plate weld model for parameter estimation towards effective wire arc additive manufacturing simulation by Strobl, Dominic, Unger, Jörg F., Ghnatios, Chady, Klawonn, Alexander, Pittner, Andreas, Rethmeier, Michael, Robens-Radermacher, Annika

“…Despite the advances in hardware and software techniques, standard numerical methods fail in providing real-time simulations, especially for complex processes…”
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A Fourier transformation‐based method for gradient‐enhanced modeling of fatigue by Kindrachuk, Vitaliy M., Titscher, Thomas, Unger, Jörg F.

“…Summary A key limitation of the most constitutive models that reproduce a degradation of quasi‐brittle materials is that they generally do not address issues…”
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Application of molecular dynamics simulations for the generation of dense concrete mesoscale geometries by Titscher, Thomas, Unger, Jörg F.

“…•Fast generation of mesostructures for concrete using a molecular dynamics simulation.•Significant increase of volume fraction compared to commonly used…”
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A regularized model for impact in explicit dynamics applied to the split Hopkinson pressure bar by Otto, Peter, De Lorenzis, Laura, Unger, Jörg F.

“…In the numerical simulation of impact phenomena, artificial oscillations can occur due to an instantaneous change of velocity in the contact area. In this…”
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