A Two‐Way Coupled Simulation Framework for the Prediction of Fire‐Induced Damage and Smoke Propagation in a Building

ABSTRACT The contribution is concerned with a fully coupled simulation methodology for fire‐induced damage in concrete structures. Fire events in buildings not only generate high temperatures and the spreading of smoke gases but also induce significant structural damages of the concrete structure. The damage alters the flow of hot gases and smoke, while evolving fire conditions influence the thermal and mechanical stresses in the structure due to the temperature‐dependent material behavior. To capture all these interacting processes, a two‐way coupled computational framework that combines fire dynamics with structural analysis, enabling realistic predictions of both material degradation and fire propagation, is developed. The dynamics of the fire, including combustion, heat transfer, and the complex turbulent fluid flow with smoke propagation, are simulated using the open‐source software Fire Dynamics Simulator ( FDS ). The structural degradation of concrete, including damage and thermo‐mechanical spalling, is modeled using a phase‐field approach implemented in a FEniCS ‐based solver. The two solvers are bi‐directionally coupled via the open‐source coupling framework preCICE , enabling the exchange of the wall temperature data from the fire solver to the structural solver and the damage information from the structural to the fluid solver. As damage evolves, the computational domain of the fluid flow simulation is dynamically updated to account for evolving damages in the concrete wall. The material degradation allows the leakage of smoke and hot gases into so far unaffected neighboring rooms, thereby influencing the progression of the fire. The applicability of the proposed two‐way coupled methodology implemented on a powerful HPC cluster is demonstrated through a representative real‐world example involving a building with two rooms and considering the fire‐induced thermal damage of a concrete wall and the resulting gas leakage.