Numerical prediction of steel fiber orientation and distribution Author: Oldřich Švec Supervisors: Henrik Stang John Forbes Olesen Lars Nyholm Thrane Three point bending test Source: internet 2 DTU Civil Engineering, Technical University of Denmark 1
What do we do? Part of a larger project Innovation consortium "Sustainable Concrete Structures using Steel Fiber Reinforced Concrete" (fund: Danish Strategic Research Council) Main task: to provide tools for better and wider usage of SFRC-SCC 3 DTU Civil Engineering, Technical University of Denmark How do we do it? We developed model capable of: Code, code, code, code Fluid Dynamics solver Non-Newtonian, Free Surface Boundary Conditions (walls, inlets, re-bars ) Solid particle model Fibers, Aggregates (spheres, ellipsoids ) Collisions and other interactions Parallelized (running on 25 cores and more) Further information in our journal paper: Free surface flow of a suspension of rigid particles in a non-newtonian fluid: A lattice Boltzmann approach Number of Files Lines Characters Eq. Pages 340 34 000 1 450 000 800 4 DTU Civil Engineering, Technical University of Denmark 2
slump spread: 600 650 mm yield stress: 45 Pa, plastic viscosity: 75 Pa s SLAB CASTING (DTI, DENMARK) 5 DTU Civil Engineering, Technical University of Denmark Computed Tomography 6 DTU Civil Engineering, Technical University of Denmark 3
Computed tomography results Bottom Third Top Third 7 DTU Civil Engineering, Technical University of Denmark Fiber orientation vs. fracture response Top Third 8 DTU Civil Engineering, Technical University of Denmark 4
Numerical Simulation 9 DTU Civil Engineering, Technical University of Denmark CT vs. Simulation Upper third of the slab 10 DTU Civil Engineering, Technical University of Denmark 5
Problem Simulation Lower third of the slab CT VS 11 DTU Civil Engineering, Technical University of Denmark Additional SLAB CASTING Collaboration between the SFRC-Consortium and the COIN project in Norway 12 DTU Civil Engineering, Technical University of Denmark 6
Mould surfaces 2 Slabs 2 Slabs Oiled laminated plywood Glued sand surface 13 DTU Civil Engineering, Technical University of Denmark Experiment vs. simulation 14 DTU Civil Engineering, Technical University of Denmark 7
F, kn F, kn Four point bending tests slippery surface Simulation 80 70 60 50 40 30 20 10 0 0,00 1,00 2,00 3,00 4,00 5,00 6,00 7,00 CMOD, mm 15 DTU Civil Engineering, Technical University of Denmark Four point bending tests rough surface Simulation 80 70 60 50 40 30 20 10 0 0,00 1,00 2,00 3,00 4,00 5,00 6,00 7,00 8,00 CMOD, mm 16 DTU Civil Engineering, Technical University of Denmark 8
Conclusions Fibers orient due to the flow of the SCC Dependent on formwork type Knowledge of the casting process is required (rheology, type of filling, surface of the formwork ) We are able to predict the final orientation and distribution of fibers Future work: Relation between Fiber orientation (i.e. fiber counts at the fracture plane ) Final mechanical properties of the elements 17 DTU Civil Engineering, Technical University of Denmark Thank you for your attention Journal papers Journal of Non-Newtonian Fluid Mechanics: Free surface flow of a suspension of rigid particles in a non-newtonian fluid: A lattice Boltzmann approach, 2012 Conference papers CMM 2011: Fully coupled Lattice Boltzmann simulation of fiber reinforced self compacting concrete flow ICCC 2011: Flow simulation of fiber reinforced self compacting concrete using Lattice Boltzmann method ICCC 2011: Modeling of flow of flow of particles in non-newtonian fluid using lattice Boltzmann method BEFIB 2012: Fibre reinforced self-compacting concrete flow simulations in comparison with L- Box experiments using Carbopol SSCS 2012: Application of the fluid dynamics model to the field of fibre reinforced selfcompacting concrete Other Nordic symposium 2011: Prediction of flow induced inhomogeneities in self compacting concrete 18 DTU Civil Engineering, Technical University of Denmark 9