Welcome to Johanna Eisenträger

Johanna EisenträgerCIES welcomes the very talented Dr Johanna Eisenträger to our research team.  Dr Eisenträger is the recipient of a major European two-year research scholarship funded by the DFG (Deutsche Forschungsgemeinschaft), German Research Foundation. Her project, which will be undertaken at CIES, is Modelling Creep of Short Fibre Reinforced Concrete (FRC).

As a modern and versatile material, short fibre reinforced concrete (FRC) is used in many applications nowadays, such as tunnel linings or marine structures. Under constant long-term loads, creep occurs both in pure concrete as well as in FRC, thus deformation will increase with time. However, to date there is no viable creep modelling approach which fully takes the complex microstructure of FRC into account. Current numerical models, as Dr Eisenträger points out, are based on simplifying assumptions resulting in a limited ability to describe actual physical processes.

Dr Eisenträger is here to put that right. Her project aims at developing a new numerical framework for creep of FRC that takes into consideration the real microstructural components of the material. Three different areas will be covered and combined in the project: experiments, constitutive modelling, and simulation with Scaled Boundary Finite Element Method (SBFEM). Experimental data will be used to set up a constitutive model for creep in SFRC, using the SBFEM.

A preliminary three-week research stay at UNSW in March 2019 enabled Johanna to better get to know Chongmin Song’s impressive group at CIES, some of whom she had met at the 2018 World Congress in Computational Mechanics (WCCM) in New York.  Having previously used only standard finite element methods, she was excited to start working with the SBFEM, which was totally new to her.  She hopes that she can reciprocate CIES expertise with her own extensive knowledge in nonlinear material modelling.

Dr Eisenträger has a PhD in applied mechanics from the University of Magdeburg in Germany, having first attained her Bachelors and Masters in mechanical engineering there.

Her research interests have always involved the mechanics of materials – such as constitutive models for rate-dependent inelasticity of steels, experimental analysis and calibration of nonlinear material models, and implementation of constitutive models into the finite element method.

She is also expert in structural mechanics, working with layerwise plate theories for laminates and photovoltaic modules; development of user-defined finite elements, and exploring stress concentration at notches considering elastic and inelastic material behavior

Most recently, she developed and implemented nonlinear constitutive models to describe the complex rate-dependent inelastic deformations of tempered martensitic steels.

The work at UNSW is her latest exciting challenge.

As Dr Eisenträger notes, engineering research and researchers are often located in two separate areas: conducting experiments (the practical part) and computational methods (the theoretical part). Her research will include both parts, a major challenge, and one, she says, which any researcher who has tried to verify simulation results with experiments will understand! Nevertheless, it is a challenge she is greatly looking forward to.

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