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Dive into the research topics where Stephan Wulfinghoff is active.

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Featured researches published by Stephan Wulfinghoff.


Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences | 2012

Equivalent plastic strain gradient enhancement of single crystal plasticity: theory and numerics

Stephan Wulfinghoff; Thomas Böhlke

We propose a visco-plastic strain gradient plasticity theory for single crystals. The gradient enhancement is based on an equivalent plastic strain measure. Two physically equivalent variational settings for the problem are discussed: a direct formulation and an alternative version with an additional micromorphic-like field variable, which is coupled to the equivalent plastic strain by a Lagrange multiplier. The alternative formulation implies a significant reduction of nodal degrees of freedom. The local algorithm and element stiffness matrices of the finite-element discretization are discussed. Numerical examples illustrate the advantages of the alternative formulation in three-dimensional simulations of oligo-crystals. By means of the suggested formulation, complex boundary value problems of the proposed plastic strain gradient theory can be solved numerically very efficiently.


arXiv: Computational Physics | 2015

Equivalent Plastic Strain Gradient Plasticity with Grain Boundary Hardening and Comparison to Discrete Dislocation Dynamics

Eric Bayerschen; Markus Stricker; Stephan Wulfinghoff; D. Weygand; Thomas Böhlke

The gradient crystal plasticity framework of Wulfinghoff et al. (Wulfinghoff et al. 2013 Int. J. Plasticity 51, 33–46. (doi:10.1016/j.ijplas.2013.07.001)), incorporating an equivalent plastic strain γeq and grain boundary (GB) yielding, is extended with GB hardening. By comparison to averaged results from many discrete dislocation dynamics (DDD) simulations of an aluminium-type tricrystal under tensile loading, the new hardening parameter of the continuum model is calibrated. Although the GBs in the discrete simulations are impenetrable, an infinite GB yield strength, corresponding to microhard GB conditions, is not applicable in the continuum model. A combination of a finite GB yield strength with an isotropic bulk Voce hardening relation alone also fails to model the plastic strain profiles obtained by DDD. Instead, a finite GB yield strength in combination with GB hardening depending on the equivalent plastic strain at the GBs is shown to give a better agreement to DDD results. The differences in the plastic strain profiles obtained in DDD simulations by using different orientations of the central grain could not be captured. This indicates that the misorientation-dependent elastic interaction of dislocations reaching over the GBs should also be included in the continuum model.


International Journal of Plasticity | 2013

A gradient plasticity grain boundary yield theory

Stephan Wulfinghoff; Eric Bayerschen; Thomas Böhlke


Journal of The Mechanics and Physics of Solids | 2015

Strain gradient plasticity modeling of the cyclic behavior of laminate microstructures

Stephan Wulfinghoff; Samuel Forest; Thomas Böhlke


International Journal of Plasticity | 2015

Gradient crystal plasticity including dislocation-based work-hardening and dislocation transport

Stephan Wulfinghoff; Thomas Böhlke


Gamm-mitteilungen | 2013

Equivalent plastic strain gradient crystal plasticity – Enhanced power law subroutine

Stephan Wulfinghoff; Thomas Böhlke


Acta Materialia | 2015

Deformation patterns in cross-sections of twisted bamboo-structured Au microwires

M. Ziemann; Ying Chen; Stephan Wulfinghoff; Christoph Kirchlechner; Nobumichi Tamura; Thomas Böhlke; Michael H. Walter; Patric A. Gruber


Pamm | 2013

Micromechanical Simulation of the Hall‐Petch Effect with a Crystal Gradient Theory including a Grain Boundary Yield Criterion

Stephan Wulfinghoff; Eric Bayerschen; Thomas Böhlke


Pamm | 2014

Conceptual Difficulties in Plasticity including the Gradient of one Scalar Plastic Field Variable

Stephan Wulfinghoff; Eric Bayerschen; Thomas Böhlke


Pamm | 2014

Application of Strain Gradient Plasticity to Micro-torsion Experiments

Eric Bayerschen; Stephan Wulfinghoff; Thomas Böhlke

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Thomas Böhlke

Karlsruhe Institute of Technology

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Eric Bayerschen

Karlsruhe Institute of Technology

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D. Weygand

Karlsruhe Institute of Technology

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M. Ziemann

Karlsruhe Institute of Technology

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Markus Stricker

Karlsruhe Institute of Technology

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Michael H. Walter

Karlsruhe Institute of Technology

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Patric A. Gruber

Karlsruhe Institute of Technology

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Vedran Glavas

Karlsruhe Institute of Technology

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Ying Chen

Karlsruhe Institute of Technology

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