Experimental Study on Fragmentation Law of Propellant Bed Under the Mechanics Situation in the Chamber

A lot of propellant grains fragmented at the bottom of projectile by the intergranular compression stress is the main reason to cause bore burst. Therefore, the test device for dynamic compression fracture of propellant charge was established to simulate the compression and fractured of propellant bed at the bottom of projectile in the chamber. Based on the Theory of two-phase flow dynamics in interior ballistics, the simulation calculation showed that the intergranular compression stress from the bottom to 30 mm from the bottom of the projectile was greater than that in other places. The application of the dynamic compression fracture device of propellant charge is used to obtain the fragmentation degrees of the propellant beds with different diameters under the same dynamic load. The simulation beds with diameters of 76 and 105 mm showed similar fragmentation degrees of the propellant beds after compression. In addition, by adjusting the initial conditions of the test, the history of compression stress obtained by the test for dynamic compression fracture of propellant charge was closed to the compression stress curve obtained by the test for the mechanics situation of propellant charge in the chamber. The research results will provide a theoretical basis for the test for dynamic compression fracture of the launching charge, and the test method for the detection and evaluation of the launch safety of propellant charge.