Dr.-Ing. Thorsten Bartel
- ehem. Wissenschaftlicher Mitarbeiter
- Lehrstuhl für Allgemeine Mechanik
- Institut für Computational Engineering
- Fakultät für Bau- und Umwelt-
ingenieurwissenschaften Raum IA 3/126- Fon +49 (0)234 /32-26025 (Sekretariat)
Fax +49 (0)234 /32-14154- E-Mail: Thorsten.Bartel@rub.de
Lehre
übungen zu den Vorlesungen Mechanik I , II und III für Studenten der Fachrichtungen Maschinenbau, Bauingenieurwesen, Umwelttechnik & RessourcenmanagementBetreuung von fachwissenschaftlichen Arbeiten (Studien- und Projektarbeiten) und DiplomarbeitenBetreuung und Durchführung des Projektes "Dynamik in Natur und Technik" im Rahmen des Schülerlabors der RUB
Forschung
- Mikromechanische Modellierung von Materialien mit martensitischen Phasentransformationen
- Multiskalen - Modellierung / Homogenisierung
- Konzeptstudien zu mikromechanischen Prozessen / Phänomenen im Rahmen von Phasentransformationen
Kurzer Lebenslauf
- 1994
- Abitur
- 1994-1995
- Zivildienst
- 1995-1998
- Ausbildung zum Bauzeichner bei der Ed. Züblin AG, Duisburg
- 1998-2003
- Studium im Fach Bauingenieurwesen an der Ruhr-Uni-Bochum
- 2003 -2008
- Wissenschaftlicher Mitarbeiter am Lehrstuhl für Allgemeine Mechanik
Publikationen
A novel approach to the modelling of single-crystalline materials undergoing martensitic phase-transformations, Materials Science and Engineering A, Vol. 481-482, pp. 371-375, (2008). |
| Abstract: We develop a micromechanical model which is suitable for any single-crystalline material which undergoes diffusionless solid-to-solid phase transitions. It is based on the specification of a microstructure accompanied by a perturbation of the local displacement-field which allows for a relaxation of the internal energy within a representative volume element. The main feature of our model is the distinction of internal variables into elastic and dissipative variables. They are treated by means of energy minimization and evolution laws, respectively. Applications are given in the context of material-point computations and two-dimensional finite-elements analysis. |
BibTeX:
@article{Bartel2008,
author = {Bartel, Thorsten and Hackl, Klaus},
title = {A novel approach to the modelling of single-crystalline materials undergoing martensitic phase-transformations},
journal = {Materials Science and Engineering A},
year = {2008},
volume = {481-482},
pages = {371-375},
doi = {http://dx.doi.org/10.1016/j.msea.2006.12.231}
}
|
Prediction of Energy Barriers due to Nucleation in Solid-to-Solid Phase-Transitions, Proceedings in Applied Mathematics and Mechanics (PAMM), Vol. 6(1), pp. 463-464, (2007). |
| Abstract: This contribution generally aims at the application of the multiscale-FEM to problems arising from inhomogeneities of arbitrary shape within a solid matrix material. In the context of our work, the inhomogeneity represents a nucleus of a new solid phase. According to the theory of homogeneous nucleation, the model predicts whether it is energetically preferable to initiate the growth of the nucleus or not. The implementation of this procedure into a micromechanical model for shape-memory alloys is assumed to be suitable to reconstruct the so-called stress-drop after the initiation of phase-transformation as observed in experiments. |
BibTeX:
@article{Bartel2007,
author = {Bartel, Thorsten and Hackl, Klaus},
title = {Prediction of Energy Barriers due to Nucleation in Solid-to-Solid Phase-Transitions},
journal = {Proceedings in Applied Mathematics and Mechanics (PAMM)},
year = {2007},
volume = {6},
number = {1},
pages = {463-464},
doi = {http://dx.doi.org/10.1002/pamm.200610212}
}
|
Relaxation and the computation of effective energies and microstructures in solid mechanics, In Analysis, modeling and simulation of multiscale problems, Berlin, Heidelberg , pp. 197-224, Springer, (2006). |
| Abstract: We address the numerical analysis of relaxed formulations for scalar and vectorial nonconvex variational problems originating from models for solid-solid phase transitions and crystal plasticity.We discuss algorithms for the approximation of the quasiconvex envelope using laminates, rank-one convexity, and polyconvexity, and present some numerical applications to benchmarks problems, and to a model for single-slip crystal plasticity. |
BibTeX:
@incollection{Bartels2006,
author = {Bartels, Sören and Carstensen, Carsten and Conti, Sergio and Hackl, Klaus and Hoppe, Ulrich and Orlando, Antonio},
title = {Relaxation and the computation of effective energies and microstructures in solid mechanics},
booktitle = {Analysis, modeling and simulation of multiscale problems},
publisher = {Springer},
year = {2006},
pages = {197--224},
doi = {http://dx.doi.org/10.1007/3-540-35657-6}
}
|
A Lamination Upper Bound to the Free Energy of Shape Memory Alloys, Proceedings in Applied Mathematics and Mechanics (PAMM), Vol. 6(1), pp. 481-482, (2006). |
| Abstract: Modeling the energetic behavior of materials showing martensitic phase transformations usually leads to non-convex energy formulations. In a variety of models based on quasi-convex analysis, the Reuß lower bound, which neglects the compatibility constraint for the deformation fluctuations, is used as an estimate for the so-called energy of mixing. We present an upper bound that is on the one hand based on the lamination mixture formula, which gives an estimate of the free energy of two-variant materials and is extended to a specialized n-variant case in our work. On the other hand, we rely on experimentally well established assumptions about the type of microstructure that forms in such alloys. More precisely, we restrict the set of physically admissible microstructures to the subset of second order laminated microstructres consisting of austenite and twinned martensites. We further refine our upper bound by taking into account the notion of twin-compatibility. For the physically relevant examples of 13- and 7-variant Cu-Al-Ni shape memory alloys, striking congruence is obtained in the comparison of the Reuß lower and our upper bound for fixed volume fractions. Furthermore, we show results of global minimization of the energy obtained by each bound over the volume fractions of the variants. Similarities and differences in the energy-minimizing volume fractions are discussed. |
BibTeX:
@article{Heinen2006,
author = {Heinen, Rainer and Hackl, Klaus and Kotucha, Gregor and Bartel, Thorsten},
title = {A Lamination Upper Bound to the Free Energy of Shape Memory Alloys},
journal = {Proceedings in Applied Mathematics and Mechanics (PAMM)},
year = {2006},
volume = {6},
number = {1},
pages = {481-482},
doi = {http://dx.doi.org/10.1002/pamm.200610221}
}
|
Multiscale Modelling Of Shape-Memory Alloys, Proceedings in Applied Mathematics and Mechanics (PAMM), Vol. 5(1), pp. 373-374, (2005). |
| Abstract: This work is dealing with the modelling and simulation of shape-memory alloys by taking into account the different scales which have a bearing on the material behaviour. Particularly we focus on the combination of all these scales in order to formulate one closed, physically well motivated model, which is capable to represent the characteristic phenomena of this kind of material. |
BibTeX:
@article{Bartel2005,
author = {Bartel, Thorsten and Hackl, Klaus},
title = {Multiscale Modelling Of Shape-Memory Alloys},
journal = {Proceedings in Applied Mathematics and Mechanics (PAMM)},
year = {2005},
volume = {5},
number = {1},
pages = {373-374},
doi = {http://dx.doi.org/10.1002/pamm.200510163}
}
|
A micromechanical model for single-crystal shape-memory alloys, Proceedings in Applied Mathematics and Mechanics (PAMM), Vol. 4, pp. 298-299, (2004). |
| Abstract: This work is dealing with solid to solid phase transformations in shape-memory-alloys and the simulation of the corresponding characteristic phenomena, e.g. pseudoelasticity and the shape-memory-effect. In particular it focuses on the micromechanical behaviour of the material and the appearance of microstructures. |
BibTeX:
@article{Bartel2004,
author = {Bartel, Thorsten and Hackl, Klaus},
title = {A micromechanical model for single-crystal shape-memory alloys},
journal = {Proceedings in Applied Mathematics and Mechanics (PAMM)},
year = {2004},
volume = {4},
pages = {298-299},
doi = {http://dx.doi.org/10.1002/pamm.200410130}
}
|
Effective relaxation for microstructure simulations: algorithms and applications, Computer Methods in Applied Mechanics and Engineering, Vol. 193(48-51), pp. 5143-5175, (2004). |
| Abstract: For a wide class of problems in continuum mechanics like those involving phase transitions or finite elastoplasticity, the governing potentials tend to be not quasiconvex. This leads to the occurrence of microstructures of in principle arbitrarily small scale, which cannot be resolved by standard discretization schemes. Their effective macroscopic properties, however, can efficiently be recovered with relaxation theory. The paper introduces the variational framework necessary for the implementation of relaxation algorithms with emphasis on problems with internal variables in a time-incremental setting. The methods developed are based on numerical approximations to notions of generalized convexification. The focus is on the thorough analysis of numerical algorithms and their efficiency in applications to benchmark problems. An outlook to time-evolution of microstructures within the framework of relaxation theory concludes the paper. |
BibTeX:
@article{Bartels2004,
author = {Bartels, Sören and Carstensen, Carsten and Hackl, Klaus and Hoppe, Ulrich},
title = {Effective relaxation for microstructure simulations: algorithms and applications},
journal = {Computer Methods in Applied Mechanics and Engineering},
year = {2004},
volume = {193},
number = {48-51},
pages = {5143-5175},
doi = {http://dx.doi.org/10.1016/j.cma.2003.12.065}
}
|
Sonstiges
Neben der gemeinsamen Freizeitgestaltung mit meiner Frau, Tochter und unserem Hund ist die Musik meine private Leidenschaft. Ich spiele selber Gitarre (hauptsächlich elektrische), schreibe Songtexte und arrangiere Lieder.