Fire Simulation and Residual Strength Prediction Tool for Aluminum Ship Structures During and After Fire

A 3D non-linear and rate-dependent constitutive model will be developed and implemented within GEM"s Abaqus Fire Interface Simulator Toolkit (AFIST) to characterize the time-, stress-, and temperature-dependent material response of aluminum alloys. Both the material and geometric non-linearities will be characterized based on Abaqus"kinematic description, coupled with its user-defined subroutines. The large deformation model will be formulated based on the additive decomposition of the strain rate tensor in elastic, thermal, and viscoplastic parts. To capture the loading and unloading path in an aluminum ship structural component during a fire, a flow rule will be formulated based on a function of the equivalent stress and the deviatoric stress tensor of the temperature field and of a set of internal state variables. Both the steady state and creep test data at coupon level will be collected to quantify the model parameters and the validity of the developed non-linear rate-dependent constitutive model will be examined via its simulation of the transient state tests. A hybrid implicit and explicit integration scheme will be implemented in AFIST to further enhance the solution efficiency and numerical stability. GEM has secured model validation support from VT and application guidance from NGSB and NSWCCD.