Project Cases Detail
Analysis of steel-reinforced concrete exposed to Fire (MFPA Leipzig GmbH)
At MFPA Leipzig GmbH, Department "Numerical Simulations" a suitable material behaviour had to be introduced for steel-reinforced concrete in order to describe the highly nonlinear behaviour under mechanical and thermal loads due to fire.
The department "Numerical Simulations" at MFPA Leipzig GmbH implements and performs numerical analyses of the developement of fire (CFD) and thereout arising loads on buildings (FEM). Before introducing Code-Aster MFPA had to validate this code for this kind of analyses. The validation report shows that the results obtained with Code-Aster satisfy the standards of DIN EN 1991-1-2 (Eurocode). The validation process was accompagnied by Ingenieurbüro für Mechanik.
Temperature dependent elastoplastic material models have been introduced. For the concrete a Double Drucker Prager law is used. Different from the simple Drucker-Prager material law which has a cone shaped yield surface, the yield surface of the Double Drucker Prager is formed by the union of two intersecting cones. The second cone cuts the peak of the first one rendering it stump. In this manner plasticity appears at lower stress levels when a body mainly suffers traction (σ1 > 0, σ2 > 0, σ3 > 0). Under compression the onset of yield is identic with that of the simple Drucker Prager material. This very particular behaviour is suited for concrete since concrete is very fragile in traction but has very high strength in compression.
Tom Guder, responsible at MFPA GmbH for structural analysis: "Code-Aster offers all material models we need to simulate concrete structures which are exposed to fire. Often tasks can be automatized by scripting with python. In this manner we simulate a huge number of parameterized concrete structures in batch runs. Result tables, plots and diagrams are all generated by the batch script. Even the technical report is ready after running Latex over the result files being stored during the batch run."