Experimental Determination of the Dynamic Initiation Fracture Toughness of Composite Modified Double base Propellant

This paper presents a detailed experimental procedure for determining the dynamic initiation fracture toughness of Composite Modified Double-Base (CMDB) propellant under dynamic loading. The Cracked Straight Through Flatten Brazilian Disc (CSTFBD) specimens were conducted using the split Hopkinson pressure bar(SHPB) system under high loading rates. Experimental setup, data acquisition and interpretation were described in details. The strain gauge was adopted to monitor the time-to-fracture accurately. We interpreted the detailed procedure of getting the time-to-fracture, as well as confirmed all the propellant specimens were in a state of dynamic force equilibrium. Experimental results show that the CMDB fracture initiation toughness depended on loading rate. The pattern of destroyed sample indicated the solid propellant material was evident brittle fracture under dynamic loads.