Frame constraint effect on the window glass crack behavior exposed to a fire

•Constraint effect on glass crack is investigated using finite element method when subjected to fire.•The crack location and the growth are predicted using Coulomb–Mohr criterion and SIFs based mixed-mode criterion.•The four edges fully constrained glass sustained longest time to crack.

Thermal caused glass crack and fracture are very common in building fire, to disclose the constraint effect on the glass crack initiation and crack propagation, five constraint cases are investigated and compared mainly on the first crack initiation time, crack propagation path using a finite element program. The crack location and the growth are predicted using Coulomb–Mohr criterion and the SIFs based mixed-mode criterion, respectively. The thermal stresses distributions, crack initiation, and crack growth path are obtained and compared. It is found that the four edges fully constrained glass sustains the longest time to crack, and then is the half constrained one, the one edge constrained glass is easiest one to crack. The no constrained glass also shows a longer time to crack than the one edge constrained condition. For the one edge constrained conditions, it has the shorter endurance time, which is a dangerous glass install method used in the building windows.