Kai Langenfeld

Modeling Fatigue-Induced Anisotropic Quasi-Brittle Damage Based on the Endurance Surface Concept

Klas Feike, Patrick Kurzeja, Kai Langenfeld, Jörn Mosler

This work proposes a novel continuum damage framework for fatigue based on the endurance-surface concept and uses the energy-release rate as the driving force. Damage evolution is governed by the distance of the thermodynamic driving force from the endurance surface. In contrast …

Modeling Fatigue-Induced Anisotropic Quasi-Brittle Damage Based on the Endurance Surface Concept

Klas Feike, Patrick Kurzeja, Kai Langenfeld, Jörn Mosler

This work proposes a novel continuum damage framework for fatigue based on the endurance-surface concept and uses the energy-release rate as the driving force. Damage evolution is governed by the distance of the thermodynamic driving force from the endurance surface. In contrast …

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A computationally efficient monolithic arc-length method for phase-field models of fracture based on the Efendiev & Mielke scheme

Felix Rörentrop, Kai Langenfeld, Jörn Mosler

Brittle fracture has been a central topic in computational mechanics for many years and remains highly relevant today. In the context of rate-independent phase-field models of brittle fracture, cracks may evolve discontinuously in time — also referred to as unstable or brutal …

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On the accuracy of isotropic damage descriptions for complex load paths—Limits quantified by numerical optimization

Klas Feike, Patrick S. Kurzeja, Jörn Mosler, Kai Langenfeld

The stress triaxiality and the Lode angle parameter are two well established stress invariants for the characterization of damage evolution. At the same time, their limitations are known in principle as they are not sufficient, but remain to be quantified for a …

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A computationally efficient monolithic arc-length method for phase-field models of fracture based on the Efendiev & Mielke scheme

Felix Rörentrop, Kai Langenfeld, Jörn Mosler

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Limits of isotropic damage models for complex load paths -- beyond stress triaxiality and Lode angle parameter

Klas Feike, Patrick S. Kurzeja, Jörn Mosler, Kai Langenfeld

The stress triaxiality and the Lode angle parameter are two well established stress invariants for the characterization of damage evolution. This work assesses the limits of this tuple by using it for damage predictions in a continuum damage mechanics framework. Isotropic and …

Limits of Isotropic Damage Models for Complex Load Paths — Beyond Stress Triaxiality and Lode Angle Parameter

Kai Langenfeld, Klas Feike, Patrick S. Kurzeja, Jörn Mosler

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On the Accuracy of Isotropic Damage Descriptions for Complex Load Paths -- Limits Quantified by Numerical Optimization

Klas Feike, Patrick S. Kurzeja, Jörn Mosler, Kai Langenfeld

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Low cycle fatigue of components manufactured by rod extrusion: Experiments and modeling

Kai Langenfeld, Lars Andree Lingnau, Jan Gerlach, Patrick S. Kurzeja et autres

The performance of formed components is significantly influenced by the initiation of ductile damage. Preceding forming operations, for instance, affect the service life determined in fatigue tests. In the current investigation, the effect of ductile damage in forming is isolated by changing …

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On the curvature dependence of gradient damage models: Control and opportunities

Kai Langenfeld, Patrick S. Kurzeja, Jörn Mosler

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On the Curvature Dependence of Gradient Damage Models: Control and Opportunities

Kai Langenfeld, Patrick S. Kurzeja, Jörn Mosler

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How regularization concepts interfere with (quasi-)brittle damage: a comparison based on a unified variational framework

Kai Langenfeld, Patrick S. Kurzeja, Jörn Mosler

Abstract Three regularization concepts are assessed regarding their variational structure and interference with the predicted physics of (quasi-)brittle damage: the fracture energy concept, viscous regularization and micromorphic regularization. They are first introduced in a unified variational framework, depicting how they distinctively evolve …

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