ABSTRACT
This paper presents a multi-physics analysis framework for estimating thermo-mechanical behavior of structures under fire conditions. The analysis framework consists of three parts. The first part is a fire-driven flow simulation in a rectangular parallelepiped domain which includes fire source and target structure. The fire simulation is conducted using Fire Dynamics Simulator (FDS). From FDS simulation, time history of temperature on the surface of structure is obtained. The second part is the data transfer by an interface model between FDS and thermo-mechanical analyses. By the interface model, the calculated surface temperature from FDS simulation is assigned to the finite element model of the structure for thermo-mechanical analysis. The third part is a nonlinear thermo-mechanical analysis for predicting the structural response under high temperatures. To validate simulation results, structural fire experiments were performed for a real-scale steel-concrete composite beam, whose design was based on the code for nuclear power plant structures of Korea. The calculated time history of displacement at the center of the beam as well as the temperature at sampling points showed good agreement with experimental results. The changes in stiffness, load-carrying capacity, and ductility of the composite beam at elevated temperatures are investigated through parametric studies.
