STUDY ON DYNAMIC FRACTURE AND MECHANICAL PROPERTIES OF A PBX SIMULANT BY USING DIC AND SHPB METHOD

摘要

The deformation and fracture of a PBX simulant were studied in this work. A pre-cracked semi-circular bending sample was loaded using a SHPB. The failure process of the sample was recorded in situ using a high speed camera. Based on the recorded images corresponding to the loading steps, the displacement and strain fields were determined using digital image correlation method. The crack opening displacement was determined. The correlation coefficient distribution was used to predict the initiation and propagation of the crack initiated from the tip of the pre-crack. In addition, the dynamic fracture toughness of the specimen was measured. The K_(IC) values were approximately 1.39 +- 0.02, 1.51 +- 0.01 and 1.87 +- 0.03 MPa(centre dot)m~(1/2) corresponding to strain rates about 382 +- 13, 455 +- 8 and 621 +- 23 s~(-1), respectively. The fracture toughness results show strong strain rate dependence.