Shear Band Evolution in Polymer Bonded Explosives Subjected to Punch Loading

Abstract

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 hardphase 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.

A Modified Set of Constitutive Models for Polymer‐Bonded Explosives that Consider Heterogeneity of Initial Cracks and Failure of Damaged Granules

“…The results showed that a dead zone forms in the strain field immediately under the punch in agreement with the slip-line solution of the punch problem. Liu et al [22] investigated shear band development and potential hot-spot initiation in PBXs using a punch-loading experiment at different temperatures. At room temperature, initiation and development of shear bands occurred in three stages and the material suffered a prolonged concentration of shear stress in one area.…”

“…Liu et al . [22] investigated shear band development and potential hot‐spot initiation in PBXs using a punch‐loading experiment at different temperatures. At room temperature, initiation and development of shear bands occurred in three stages and the material suffered a prolonged concentration of shear stress in one area.…”

Simultaneous Determination of Multiple Mechanical Parameters for a DNAN/HMX Melt‐Cast Explosive by Brazilian Disc Test Combined with Digital Image Correlation Method

“…Thus far, the DIC method has been used to investigate various mechanical parameters (e.g., Young's modulus, Poisson's ratio, stress intensity factor, residual stress, and thermal expansion coefficient) of various materials (e.g., metal, composite, polymer, and biological materials) [7][8][9][10][11][12][13][14][15][16][17][18][19]. Moreover, the method is being continuously developed and enlarging its application area [20][21][22]. Recently, the method has been applied to analyze the viscoelastic Poisson's ratio of solid propellants [23,24].…”