The Impact of Various Heating Rates on Real-Time Degree of Hybrid Fire Simulation

Global fire performance of structures in fire is proven to be more advantageous in many cases of engineering practice than the prescriptive fire resistance based on isolated structural member testing. Hybrid fire simulation (HFS) is a novel well-suited method trending in recent years for analysis of global performance of structures in fire. In the principles of this method, the part of a structure which has unknown behavior or is uncertain to be numerically modeled (subjected to fire) would be physically tested, while the rest of the structure is numerically simulated. HFS method enables capturing the beneficial interaction mechanisms evolving between fire-exposed structural members and the adjacent cooler substructure. Due to the continuous temperature increase in a fire test and the existing thermal inertia as well as the rate- and temperature-dependent material behavior of structures exposed to fire, a real-time performance in hybrid fire simulation counts as a necessity. This challenge is more critical for hybrid fire simulations with higher applied heating rates relevant to structural fire engineering. Within scope of this paper, (a) a robust and rigorous approach for real-time HFS is presented; (b) a series of proof-of-concept studies of different hybrid fire simulations with various applied heating rates are carried out for a thermomechanical benchmark problem; (c) the important results of four representative hybrid fire simulations with relevant heating rates to structural fire engineering are discussed; (d) the importance of an appropriate calculation method for stiffness update of the fire-exposed structural member over HFS procedure is highlighted, and e) the precision and accuracy of the applied HFS approach with respect to interface error and real-time degree are evidenced.