A Real-Time Hybrid Fire Simulation Method Based on Dynamic Relaxation and Partitioned Time Integration

Abstract

The use of simplified numerical substructures in hybrid fire simulation is clearly advantageous as long as the resulting simulation accuracy is sufficient. However, excluding geometrical and material nonlinearities from the numerical substructure might make a significant difference in internal force redistribution and reduce the simulation accuracy beyond acceptable levels. Also, materials at a high temperature very often exhibit time-dependent behavior, including strain-rate dependency, high-temperature creep, and stress relaxation, which prohibit the use of extended testing time scales. This standpoint motivated the development of the real-time hybrid fire simulation method presented in this paper. Dynamic relaxation is proposed to solve the static response of the hybrid numerical-experimental fire simulation. As an equivalent dynamic solution method, dynamic relaxation allows for coupling substructure equations of motion by using a partitioned time integration approach. Minimal data exchange between substructures and negligible computational overhead plus ease of reusability of verified finite-element software makes the proposed algorithm suitable for coordinating real-time hybrid fire simulations. The hybrid fire simulation of a virtual steel frame case study is reported as a validation example.