COMPLAS 2023

Phenomenological material model for failure in reinforced high performance concretes at low cycle fatigue

  • Brands, Dominik (University of Duisburg-Essen)
  • Pise, Mangesh (University of Duisburg-Essen)
  • Gebuhr, Gregor (Bergische Universität Wuppertal)
  • Anders, Steffen (Bergische Universität Wuppertal)
  • Schröder, Jörg (University of Duisburg-Essen)

Please login to view abstract download link

In the recent decades great research effort has been carried out which led to more efficient and stronger concrete types, e.g. high performance concrete (HPC) and ultra-high performance concrete (UHPC). The steel fibers and short-wire fibers are usually added to ensure ductility during fracture in HPC and in UHPC, respectively, by transmitting the stresses in concrete from matrix to fibers. This process shows pronounced effect on the deterioration characteristics of concrete in cyclic flexural tests. In this contribution, the aim is to investigate the influence of fiber’s orientations and distribution on the overall material behavior of fiber reinforced HPCs at low cyclic fatigue. A macroscopic model is developed by combining the superposed models of transversal isotropic elasto-plasticity, and a continuum phase-field model of fracture in elasto-plastic material. Two different continuous stepwise linearly approximated degradation functions for the modeling of unsymmetric behavior of concrete materials in tension and in compression are considered. The numerical model is calibrated using the experimental data and by simulating the typical uniaxial cyclic tests and three-point bending beam test at low cycle for pure concrete specimens. Three-point bending beam tests at low cycle for reinforced HPCs with different fiber contents and orientations are simulated. To incorporate the different distributions and orientations of reinforced fibers different orientation distribution functions (ODF) are constructed and implemented. The degradation of residual stiffness is calculated using experimental and numerical results and compared to validate the accuracy of the numerical results.