Fracture behavior of prestressed ductile target subjected to high velocity impact - Numerical study

Impact studies are performed to evaluate the ballistic performance of material subjected to a high strain rate. At high velocities, the projectile penetrates through the material which leads to a fracture of the target body. The fracture behavior depends upon the condition of the target body. It is anticipated that the fracture behavior should depend upon the prestress condition of the target. Considering the aforementioned concern, the thermo-elastic-plastic finite element model is formulated using MSC Marc Mentat to analyze the effect of the prestress condition of the target body on fracture behavior. A detailed comparison has been presented considering four different prestress states subjected to impact by a blunt-shaped projectile. The continuum damage mechanics using a stress triaxiality-based damage model is used to simulate damage evolution and fracture. It is found that the presence of prestress alters the overall fracture response of the structure subjected to high strain rate deformation. In the presence of tensile prestress, the material resists the accumulation of damage which is due to the lower values of stress triaxiality and equivalent plastic strain. It is also found that the presence of tensile prestress inside the target body increases the ballistic performance, whereas the presence of compressive prestress inside the target body degrades the performance.