Financing
The project is sponsored by the Danish Research Council for Technology and Production Science (FTP) and the partners.
Research Significance
The present project will transfer the highly developed scientific approach on computational modelling of mould filling of metals and plastics to civil engineering. Through the project generalized material models will be further developed to allow for modelling of the non-Newtonian flow, thixotropic behaviour and possible segregation of suspensions. Eventually, the approach will allow for development of more realistic service life models for concrete structures by introducing modelling of the initial state of the structure, including variations of material properties and hidden defects, and residual stresses and cracks associated with the hardening process. |
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Research plan
The research plan comprises the following activities
| Activity I: |
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Establishment of modelling strategy: Conventional flow modelling software such as Fidap, Flow 3D or MAGMASOFT® is anticipated used. |
| Activity II: |
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Establishment of
PhD-Byg: an analytical model for prediction of restricted flow and shear induced segregation in self compacting concrete. Segregation will be treated in a multi-scale approach leading to a micro mechanically based failure criterion, which will be applied in “hot spots” with critical shear rates and gradients. PhD-MEK: a modelling framework for a) homogeneous flow, including weak interfaces and form pressure (from structuration rate) b) heterogeneous flow comprising shear induced segregation and blocking. |
| Activity III: |
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Simulation of existing experimental data, where segregation was systematically measured after a well documented casting process. The activity will result in identification of needs for model revision and of benchmark cases. |
| Activity IV: |
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Model revision. Model experiments and materials tests are foreseen in this activity. |
| Activity V: |
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Simulation and experimental testing of selected benchmarking cases. To the extent possible, the project will make use of existing benchmark cases. The activity will result in a preliminary documentation of the applicability of the computation model and include a preliminary assessment of the influence of heterogeneous flow on the resulting mechanical and durability related properties and ultimately the structural behaviour. |
| Activity VI: |
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Knowledge consolidation and final dissemination. |
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Connection to Earlier and Ongoing Research
A basis for the present project is innovative results of a recent industrial PhD project at DTU Byg and DTI and recent work by Roussel and co-workers at LCPC in France. Also a recent model for thixotropy of fresh concrete by Roussel will form part of the basis for the work.
In metal casting processes, substantial achievements regarding both process understanding and optimization of industrial parts have been obtained at DTU MEK by the coupled numerical modelling of mould filling solidification, microstructure development and stress-strain phenomena. These complex analyses are today carried out on a regular basis by commercial software codes like MAGMASOFT, which is the world’s leading simulation system for such simulations [www.MAGMASOFT.com]. Recently, a yield stress fluid which can be used as model material, Carbopol Ultrez10, for testing segregation was identified