Mineral-bonded composites
for enhanced structural impact safety

Mineral-bonded composites
for enhanced structural impact safety

Mineral-bonded composites
for enhanced structural
impact safety

B2/I Modelling fiber-matrix bond and mineral-bonded composites under impact loading

The aim of this subproject is to make a numerical model of cement based composites which fibers are modeled explicitly and represented by embedded elements.

To this aim, our in-house program CaeFem has been developed to analyze simple regular discretization of heterogeneous mesoscopic continuum with discrete distinction of aggregates or void from a matrix with different discretization approaches and comparisons are made with a commercial FEM program-DIANA. A material model is implemented and assigned to bond element to connect embedded fibers to continuum which fibers are distributed randomly within the simply discretized continuum. The next three steps will be: modeling of random geometry (for position, orientation and length of fibers, position and size of aggregates, comparison of approaches to model continuum with embedded fibers and embedded smeared or discrete cracks using FEM (SDA and X-FEM), EFG and iso-geometric methods and implementation of physical nonlinearities regarding fiber, bond, aggregates, matrix. Incidentally, the behavior of composite under quasi-static loading, as a necessary prerequisite for dynamics, will be validate by experiment results provided by Institut für Baustoffe.

Finite Element discretization with explicit aggregate representation
Finite element discretization with explicit fiber representation
Current challenge:
Modelling the behavior of high strength SHCCs (Strain-hardening cement-based composites) made with high performance polymer fibers under quasi-static tensile loading. High density polyethylene fibers are modelled explicitly and distributed randomly in a two-Dimensional model. Single fiber pullout test result is used for micromechanical characterization of bond strength. Load test simulations are conducted with in-house program CaeFem and comparisons will be made with experimental results. Several sensitivity analysis will perform based on different fiber contents and notches located in the mid-height of a dumbbell specimen. The resultant behaviors will be compared and verified versus obtained results from.
Thin SHCC specimen in a tensile test for calibration of 2D FEM simulations
(a)
Thin SHCC specimen with notch
(b)
Mesh properties and boundary conditions in 2D simulation of an SHCC specimen
(c)
Simulation showing crack pattern in a notch specimen under quasi static tensile loading
(d)
  1. Thin dumbbell specimen and Test set-up,
  2. Specimen with notch,
  3. Simulation of notch area and
  4. Crack pattern for notch model under quasi static tensile loading

Contributors

© André Terpe

Doctoral Researcher
(2017-2020)

Dr.-Ing. Alaleh Shehni

Contact

Institute for Solid Construction

August-Bebel-Straße 30
01219 Dresden
Germany

© Ulrich van Stipriaan

Principal Investigator

Univ.-Prof. Dr.-Ing. habil. Ulrich Häußler-Combe

Contact

Institute of concrete structures

ABS, Floor 05, Room 009
August-Bebel-Straße 30/30A
01219 Dresden
Germany

in cooperation with

Prof. Dr.-Ing. Christina Scheffler

Contact

Institute of Textile Machinery and High
Performance Material Technology (ITM)

Hohe Straße 6, Room 138
01069 Dresden
Germany