Lehrstuhl fÜR Mechanik - MATERIALTHEORIE

PROF. Dr. rer. nat. Klaus Hackl

Dr.-Ing. Sandra Klinge, (geb. Ilic), M. Sc.

• Wissenschaftliche Mitarbeiterin
• Lehrstuhl für Allgemeine Mechanik
• Institut für Computational Engineering
• Fakultät für Bau- und Umwelt-
  ingenieurwissenschaften
• Raum IA 3/139
• Fon +49 (0)234 /32-26552
• Fax +49 (0)234 /32-14154
• E-Mail: Sandra.Klinge@rub.de

Lehre, Teaching Activites

• Mechanik I, II und III (exercises, in German)
• Continuum Mechanics (exercises, in English)
• Mitbetreuung des Messtechnischen Laborpraktikums (in German)
• Finite Element Technology (lectures in English)
• Computerorientierte Lösungsverfahren (lectures in German)
• Mikromechanik (lectures in German)

Forschung, Research

Theory of homogenization

The main topic of the research work is concerned with the theory of homogenization and its application to statistically uniform materials, a group of materials for which a so-called representative volume element (RVE) can be defined. The approach is based on the idea of defining micro- and macro boundary value problems (BVP) which are related to each other by using the principle of the volume average and the Hill-Mandel macrohomogeneity condition. The latter requires the equality of the macrowork with the volume average of the microwork and is used to define the boundary conditions for the RVE.

Modeling of diffusion processes at the boundary of crystals

A particular case known as the solution-precipitation creep has recently been explored. This process is believed to be the leading deformation process in the subduction zone, and thus responsible for plate tectonics. The process shows similarities to the Coble creep with the difference that the material transport takes place in intercrystalline space and not along the boundary of crystals. For its modeling, a variational approach has been devised in which the elastic energy remains in the standard form but a novel, specific formulation of the dissipation functional is proposed.

Modeling of wave propagation through fluids and elastic solids

In this research field, the focus rests on the harmonic excitation and modeling of viscous effects. For this purpose, a formulation in the complex domain is assumed. This approach is illustrated on the basis of the modeling of the cancellous bone and the investigation of the process of osteoporosis. The cancellous bone is a specific tissue consisting of the solid skeleton and the fluid marrow for whose laboratory investigation ultrasonic procedures are typically used. These experiments are also subjects of simulations, particularly used to calculate the attenuation coefficient which depends on the bone density. [Joint work with Prof. Dr. rer. nat. R. P. Gilbert]

Software - Multiscale FE program MSFEAP

As the main result of the work on the above topics, the multiscale FE program MSFEAP has been written. This program uses the FE program FEAPpv (Robert L. Taylor, University of California, Berkeley) as a basis. Its extension, the MSFEAP program, is suitable for simulating heterogeneous materials. The user interface and commands specific to the original program remain unchanged with the difference that the commands can be applied at two levels. A further extension of the program by implementing new elements is easily possible due to its modular structure. In order to clarify the basics of the homogenization theory and the application of the program, a user manual including characteristic examples is compiled. The complete input files for the described problems are also provided.

• MSFEAP - Executable program for Windows msfeap.zip
• MSFEAP - User manual msfeap-manual.pdf
• MSFEAP - Example input files msfeap-examples.zip

Kurzer Lebenslauf

10/2002-heute

Wissenschaftliche Mitarbeiterin am Lehrstuhl für Allgemeine Mechanik

Publikationen

@article{Ilic2008,
  author = {Ilic, Sandra and Hackl, Klaus and Gilbert, Robert P.},
  title = {Effective parameters of cancellous bone},
  journal = {Proceedings in Applied Mathematics and Mechanics (PAMM)},
  year = {2008},
  url = {http://www3.interscience.wiley.com/journal/122217846/abstract}
}

@article{Ilic2007,
  author = {Ilic, Sandra and Hackl, Klaus},
  title = {Application of the multiscale FEM to the modeling of heterogeneous ma-terials},
  journal = {Proceedings of the rst seminar on The Mechanics of $},
  year = {2007}
}

@article{Ilic2007a,
  author = {Ilic, Sandra and Hackl, Klaus and Gilbert, Robert P.},
  title = {Estimation of material properties of cancellous bone using multiscale FEM},
  journal = {Proceedings in Applied Mathematics and Mechanics (PAMM)},
  year = {2007},
  url = {http://www3.interscience.wiley.com/journal/121371329/abstract}
}

@article{Ilic2006,
  author = {Ilic, Sandra and Hackl, Klaus},
  title = {Multiscale FEM in modelling of solution-precipitation creep},
  journal = {Proceedings in Applied Mathematics and Mechanics (PAMM)},
  year = {2006},
  url = {http://www3.interscience.wiley.com/journal/114078339/abstract}
}

@article{Hackl2005,
  author = {Hackl, Klaus and Ilic, Sandra},
  title = {Solution-precipitation creep - continuum mechanical formulation and micromechanical modelling},
  journal = {Archive of Applied Mechanics (Ingenieur Archiv)},
  year = {2005},
  volume = {74},
  number = {11-12},
  pages = {773-779}
}

@article{Hackl2005a,
  author = {Hackl, Klaus and Ilic, Sandra},
  title = {Solution-precipitation creepÔÇöcontinuum mechanical formulation and micromechanical modelling},
  journal = {Archive of Applied Mechanics (Ingenieur Archiv)},
  year = {2005}
}

@article{Ilic2005,
  author = {Ilic, Sandra and Hackl, Klaus},
  title = {Solution-precipitation creep-micromechanical modelling and numerical results},
  journal = {Proceedings in Applied Mathematics and Mechanics (PAMM)},
  year = {2005},
  url = {http://www3.interscience.wiley.com/journal/112191130/abstract}
}

@article{Ilic2004,
  author = {Ilic, Sandra and Hackl, Klaus},
  title = {Homogenisation of random composites via the multiscale finite-element method},
  journal = {Proceedings in Applied Mathematics and Mechanics (PAMM)},
  year = {2004},
  url = {http://www3.interscience.wiley.com/journal/109802045/abstract}
}

Sonstiges

Inhalt

• Lehre
• Forschung
• Lebenslauf
• Publikationen
• Sonstiges