Experimental and computational investigation on dynamic fracture toughness (J) behavior of multi-pass SMA armor steel weldments

Dynamic fracture toughness (J1d) behavior of shield metal arc (SMA) welding of armor grade Armox 500 T steels prepared with low hydrogen ferritic steel (LHF) and austenitic stainless (ASS) steel consumables have been evaluated and compared. Three different techniques have been described and implemented to evaluate the dynamic fracture toughness (J1d) of investigated materials. Further, the results have been compared with Elastic plastic fracture mechanics (EPFM) approach. An investigation has also been performed regarding the influence of microstructures (for LHF and ASS weldments fusion zone) effect on dynamic fracture toughness (J1d) and fracture characteristic. Finally, a constrained optimization procedure of minimizing the mean absolute percent error (MAPE) has been used to determining the Johnson Cook (JC) hardening and Damage model for Armox 500 T to simulate the impact and damage behavior. Results revealed that, Dynamic fracture toughness (J1d) of weldment-2 (prepared by ASS consumables and consisted duplex microstructure) is 20% and 10% more than weldments-1 (prepared by LHF consumables and consisted acicular ferrite structure) and counterpart base metal (Armox 500 T). The MAPE and standard deviation between FEA and experimental results are less than 10% with a good value of regression coefficient (R) which shown the excellent prediction capability of developed model.