Dynamic fracture and reaction coupling mechanism in plasticity-enhanced Al/Ni reactive materials under high overload

This study investigates the coupling mechanism between fracture damage evolution and impact energy release in reactive materials under high overload conditions. To this end, a plasticity-enhanced Al/Ni reactive material was developed via hot pressing. The mechanical response of the material at varying temperatures and strain rates was characterized using dynamic and static compression testing, enabling calibration of its Johnson-Cook (JC) constitutive parameters. Combining the chemical reaction kinetics, a user-defined material subroutine (UMAT) based on the JC model was developed to simulate the coupled fracture-reaction process of the Al/Ni material under high-impact loading, with experimental validation of the model predictions. Experimental results indicate that at a strain rate of 10 −3 s −1 , the fracture true strain of the material is 28% higher than that of conventional Al/Ni composites. The stress-strain curves obtained from split Hopkinson pressure bar (SHPB) tests exhibit an error margin within 10% when compared to numerical simulations. Under detonation loading, the fracture mode predicted by numerical simulation agrees well with experimental observations, with crack initiation occurring in the localized damage zone at the specimen mid-section in both cases. Furthermore, the simulated fragment size distribution and fracture surface morphology closely match those observed experimentally. Integrative analysis reveals the fracture-reaction coupling mechanism governing the dynamic failure of plasticity-enhanced Al/Ni composites under high-strain-rate impact loading. • Plasticity-enhanced Al/Ni reactive material has 28% higher limiting true strain than conventional Al/Ni materials. • A novel reactive material constitutive model was developed by coupling constitutive model with reaction kinetics. • Fracture-reaction coupling effect was systematically investigated via adjustable detonation numerical simulation.