The three research groups at the Institute for Structural Mechanics:



Computational Intelligence and Structural Reliability




The Research Group on „Computational Intelligence and Structural Reliability“ is working on numerical simulation approaches of structures and processes under consideration of uncertainty. In addition to stochastic approaches, polymorphic uncertainty models are investigated to combine aleatory and epistemic uncertainty. For simulation based reliability predictions of complex structures and processes, model reduction techniques are developed especially based an Artificial Neural Networks and the Proper Orthogonal Decomposition. The Research Group is also working on optimization approaches for robust and durable reinforced concrete and fiber reinforced concrete structures.



Research interests


  • Polymorphic Uncertainty Modelling
  • Reliability Analysis of Structures
  • Numerical Surrogate Models
  • Real-Time Simulation
  • Optimization of Structures and Processes


Relevant projects


Process-Oriented Simulation Models for Mechanized Tunneling


Subproject C1 of the DFG Collaborative Research Center 837 „Interaction Modeling in Mechanized Tunneling“
SFB 837 - Subproject C1



Optimization Approaches for Robust and Durable Reinforced Concrete and Fibre Concrete Structures under Consideration of Scale Bridging Polymorphic Uncertainty Modelling


Subproject 6 of the DFG Priority Program 1886 „Polymorphic Uncertainty Modelling for the Numerical Design of Structures“
SPP 1886 - Subproject 6



Fusion of Machine Learning and Numerical Simulation for Real-Time Steering in Mechanized Tunneling


MERCUR-Project (in cooperation with the Chair of Artificial Intelligence at TU Dortmund)
MERCUR-Project



Research team


Prof. Dr. techn. Meschke, Günther
Dr.-Ing. Freitag, Steffen Group Leader: Computational Intelligence and Structural Reliability
M.Sc. Kremer, Katharina Research Assistant
Dr.-Ing. Cao, Ba Trung Research Assistant
M.Sc. Edler, Philipp Research Assistant
M.Sc. Neu, Gerrit Research Assistant


Publications


  1. Cao, B.T.; Freitag, S.; Meschke, G. A fuzzy surrogate modelling approach for real-time settlement predictions in mechanised tunneling. International Journal of Reliability and Safety, 12 (1/2), 2018, pp. 187 – 217 Special Issue on Computing with Polymorphic Uncertain Data Link: DOI: 10.1504/IJRS.2018.10013808
  2. Meschke, G.; Cao, B.T.; Freitag, S. Reliability Analysis and Real-Time Predictions in Mechanized Tunneling. In: Beer, M.; Huang, H.; Ayyub, B.M.; Zhang, D.; Phillips, B.M. (eds.), Resilience Engineering for Urban Tunnels, Chapter 2, ASCE, Reston, 2018, pp. 13 – 27 Link: DOI: 10.1061/9780784415139.ch02
  3. Freitag, S.; Edler, P.; Kremer, K.; Meschke, G. Surrogate modelling for solving optimization problems with polymorphic uncertain data. In: Proceedings of the 8th International Workshop on Reliable Engineering Computing (REC 2018), Liverpool, UK, 2018, pp. 31 – 39
  4. Edler, P.; Freitag, S.; Kremer, K.; Meschke, G. Optimization of Durability Performance of Reinforced Concrete Structures under Consideration of Polymorphic Uncertain Data. In: Proceedings of the joint ICVRAM ISUMA UNCERTAINTIES conference, Florianópolis, Brazil, 2018, pp. 1 – 19
  5. Neu, G.; Gall, V.E.; Freitag, S.; Meschke, G. Robust Design of Hybrid Steel Fiber Reinforced Concrete Tunnel Lining Segments. In: Computational Modelling of Concrete and Concrete Structures (EURO-C 2018), Bad Hofgastein, Austria, 2018, pp. 715 – 723
  6. Ninic, J.; Freitag, S.; Meschke, G. A hybrid finite element and surrogate modelling approach for simulation and monitoring supported TBM steering. Tunnelling and Underground Space Technology, 63, 2017, 12 – 28 Link: DOI: 10.1016/j.tust.2016.12.004
  7. Freitag, S.; Kremer, K.; Hofmann, M.; Meschke, G. Numerical Design of Reinforced Concrete Structures under Polymorphic Uncertain Conditions. In: Bucher, C.; Ellingwood, B.R.; Frangopol, D.M. (eds.), Safety, Reliability, Risk, Resilience and Sustainability of Structures and Infrastructure, Proceedings of the 12th International Conference on Structural Safety and Reliability (ICOSSAR 2017), Vienna, Austria, 2017, pp. 1535 – 1542
  8. Cao, B.T.; Freitag, S.; Meschke, G. A hybrid RNN-GPOD surrogate model for real-time settlement predictions in mechanised tunnelling. Advanced Modeling and Simulation in Engineering Sciences, 3 (5), 2016, pp. 1 – 22 Special Issue Model order reduction: POD, PGD and reduced bases Link: DOI: 10.1186/s40323-016-0057-9
  9. Freitag, S. Artificial Neural Networks in Structural Mechanics In: Tsompanakis, Y.; Kruis, J.; Topping, B.H.V. (eds.), Computational Technology Reviews, Saxe-Coburg Publications, Stirlingshire, Volume 12, 2015, pp. 1 – 26 Link: DOI: 10.4203/ctr.12.1
  10. Freitag, S.; Cao, B.T.; Ninic, J.; Meschke, G. Hybrid surrogate modelling for mechanized tunnelling simulations with uncertain data. International Journal of Reliability and Safety, 9 (2/3), 2015, pp. 154 – 173 Special Issue on Reliability and Computations of Infrastructures Link: DOI: 10.1504/IJRS.2015.072717




Scale-bridging modelling of materials and structures




Accurate and predictive simulations of material and structural behavior greatly reduces the time and costs associated with the development of new materials and aid in the development of suitable technologies for improving their service-life. The behavior of such materials and structures is in general governed by aspects that are relevant at multiple length and time scales.
Goals of our research group is the characterization and design of materials and structures considering features at various length and time scales using mathematical models, scale-bridging methods and computational simulations.


Research interests


  • Multiscale Modelling of Concrete Durability and Deterioration under Combined Loads
  • Modelling of Fracture and Damage in Quasi-brittle Materials
  • Additive Manufacturing of Concrete Structures
  • Data-driven Material Design



Relevant projects


Computational modelling of alkali transport and ASR-induced damage in concrete


FOR AKR 1498



Damage analyses and concepts for damage-tolerant tunnel linings


Subproject B2 of the DFG Collaborative Research Center 837 „Interaction Modeling in Mechanized Tunneling“
SFB 837 - Subproject B2



Simulation of processes at the cutting wheel and in the excavation chamber


Subproject C4 of the DFG Collaborative Research Center 837 „Interaction Modeling in Mechanized Tunneling“
SFB 837 - Subproject C4



Influence of microfibers on the degradation of high-performance concrete under cyclic loading


SPP 2020
SPP 2020



Research team


Prof. Dr. techn. Meschke, Günther
Dr. Timothy, Jithender Jaswant Group Leader: Scale-Bridging Modelling of Materials and Structures
M.Sc. Yan, Xiao Research Assistant
M.Sc. Butt, Sahir Nawaz Research Assistant
M.Sc. Gudzulic, Vladislav Research Assistant
M.Sc. Iskhakov, Tagir Research Assistant
M.Sc. Peters, Simon Research Assistant
M.Sc. Reinold, Janis Research Assistant
M.Sc. Williams Moises, Rodolfo Javier Research Assistant


Publications


  1. T. Iskhakov, J.J. Timothy, and G. Meschke, Expansion and deterioration of concrete due to ASR: Micromechanical modeling and analysis. Cement and Concrete Research, 2018 (in print)
  2. V. Gudzulic, T.S. Dang, and G. Meschke, Computational modeling of fiber flow during casting of fresh concrete. Computational Mechanics, 2018 (in print)
  3. J.J. Timothy and G. Meschke, Effective diffusivity of porous materials with an isotropic and anisotropic distribution of microcracks - self-similar mean-field homogenization and pixel finite element simulations. Transport in Porous Media, 2018, (in print) Link: DOI: 10.1007/s11242-018-1126-y
  4. I. Gudzlicz, V. and. Khisamitov, J.J. Timothy, and G. Meschke, Simulation-based investigation of the influence of the micro-structure and disorder on damage evolution in concrete. Proceedings in Applied Mathematics and Mechanics, 2018 (in print)
  5. S. Butt and G. Meschke, A rate-dependent damage model for prediction of high-speed cracks. Proceedings in Applied Mathematics and Mechanics, 2018 (in print)
  6. J. J. Timothy, T. Iskhakov, Y. Zhan and G. Meschke, Strain-Hardening Cement-Based Composites (RILEM Bookseries 15), volume 15, chapter: A multiscale model for high performance FRC, pages 97-105. Springer, September 2017
  7. J. J. Timothy and G. Meschke, The intrinsic permeability of microcracks in porous solids: Analytical models and lattice boltzmann simulations. International Journal for Numerical and Analytical Methods in Geomechanics, 41(8):1138-1154, 2017.
  8. S. Butt, J.J. Timothy and G. Meschke, Wave dispersion and propagation in state-based peridynamics. Computational Mechanics, 60(5):725-738, 2017.
  9. R. Przondziono, J. J. Timothy, F. Weise, E. Krütt, R. Breitenbücher, G. Meschke and M. Hofmann, Degradation in concrete structures due to cyclic loading and its effect on transport processes. Structural Concrete, 18(4):519-527, 2017.
  10. J.J. Timothy and G. Meschke, Cascade lattice micromechanics model for the effective permeability of materials with microcracks. Journal of Nanomechanics and Micromechanics




Computational Modeling in Tunneling and Underground Structures





The Research Group on „Computational Modeling in tunneling and Underground Structures” is concerned with the developments of computational simulation models and numerical techniques for analyzing complex underground structures and processes, in particular in mechanized tunneling. One of the main focuses of this research group is the holistic process oriented numerical modeling of the mechanized tunneling process (ekate). Several advanced numerical methods, e.g. FEM, PFEM, Immersed Boundary (IB) method, Finite Cell Method and Peridynamics, are employed to model the involved physical phenomena in each individual process. With the move toward digitalization and high performance computing, this research group is also concerned with the integration of parallelization strategies and Building Information Modeling (BIM) within the numerical simulations.


Research interests


  • Numerical Simulation in Mechanized Tunneling
  • Ground Models and Soil Freezing
  • Safety Assessment of Underground Structures
  • Safety Assessment of Underground Structures
  • Simulation Models for Excavation and Material Transport



Relevant projects


Process-Oriented Simulation Models for Mechanized Tunneling


Subproject C1 of the DFG Collaborative Research Center 837 „Interaction Modeling in Mechanized Tunneling“
SFB 837 - Subproject C1



Simulation of Processes at the Cutting Wheel and in the Excavation Chamber


Subproject C4 of the DFG Collaborative Research Center 837 „Interaction Modeling in Mechanized Tunneling“
SFB 837 - Subproject C4





Research team


Prof. Dr. techn. Meschke, Günther
Dr.-Ing. Alsahly, Abdullah Group Leader: Computational Modeling in Tunneling and Underground Structures
M.Sc. Bui, Hoang Giang Research Assistant
Dr.-Ing. Dang, Thai Son Research Assistant
M.Sc. Gottardi, Nicola Research Assistant
Dr.-Ing. Hofmann, Michael Research Assistant
M.Sc. Leon Bal, Abdiel Research Assistant
M.Sc. Marwan, Ahmed Research Assistant
M.Sc. Williams Moises, Rodolfo Javier Research Assistant


Publications


  1. Alsahly, A.; Callari, C.; Meschke, G.: An algorithm based on incompatible modes for the global tracking of strong discontinuities in shear localization analyses. Computer Methods in Applied Mechanics and Engineering 330 (2018), S. 33–63
  2. Alsahly, A.; Stascheit, J.; Meschke, G.: Advanced finite element modeling of excavation and advancement processes in mechanized tunneling. Advances in Engineering Software 100 (2016), S. 198–214
  3. Obel, M.; Marwan, A.; Alsahly, A.; Freitag, S.; Mark, P.; Meschke, G.: Schadensbewertungskonzepte für innerstädtische Bauwerke bei maschinellen Tunnelvortrieben. Bauingenieur (2018), im Druck
  4. Dang, T. S.; Meschke, G.: A Shear-Slip Mesh Update – Immersed Boundary Model for Computational Simulation of Material Transport in EPB Tunnel Boring Machines. Finite Elements in Analysis and Design (2018), Nr. 142, S. 1-16
  5. Bal, A. L.; Hoppe, U.; Dang, T.; Hackl, K. & Meschke, G.: A hypoplastic particle finite element model for cutting tool-soil interaction simulations: Numerical analysis and experimental validation. Underground Space (2018)
  6. Alsahly, A.; Gall, V. E.; Marwan, A..; Scheffer, M.; König, M.; MESCHKE G., BIM-to-FEM: Incorporating Numerical Simulations into BIM Concepts with Application to Real Tunneling Projects. Proceedings of the World Tunneling Congress, 2017