Shear Band Evolution in Polymer Bonded Explosives Subjected to Punch Loading

The shear band development and potential hot-spot initiation of polymer-bonded explosive were investigated under low-rate punch loading and combined punch and thermal loading. The digital image correlation method was used for deformation analysis. The obtained results showed that the initiation and development of shear bands at room temperature occur in three stages and demonstrated that the material suffers a prolonged shear stress concentration in a local area. Large shear was shown to lead to the formation of slip bands in the hard-phase area, indicating that this region has the highest potential to initiate hot-spots even under low-rate punching. For high temperatures, the initiation and development of shear bands occur in two stages, with the resulting flow field being close to Hill's solution except for a small area directly underneath the punch. Large plastic flow rate was shown to be another important feature besides shear banding.