Fracture stress triaxiality of Ti-6Al-4V for computational design of damage tolerant aeroengines

Fracture stress triaxiality affects the maximum deformation of materials, and reliable computational design of damage-tolerant aircraft depends on accurate predictions of this state variable. This numerical study analyses the effect of fracture stress triaxiality on the damage behavior of Ti-6Al-4V during aero-engine fan blade-out events using explicit dynamic finite element analysis. Experimental data used in previously reported model calibration are compared with analytical predictions of the Johnson-Cook damage model and with preliminary simulation results of stress-triaxiality at fracture in the shroud due to a fan blade-out. This analysis is necessary to ensure that the structural integrity assessment with the identified model is consistent with the stress-triaxiality range observed in the real case of damaged engine shroud. The main result emphasizes the importance of adequate experimental calibration for accurate modelling of structural assessment of aeroengines.