NONDETONATIVE EXPLOSIONS AND BURNING OF COMPOSITION-B EXPLOSIVE

This paper describes experiments towards establishing a predictive capability for nondetonative reactions in confined explosive systems. Composition-B was confined in steel tubes of various thicknesses and pressurized in separate experiments by self combustion and at various rates with a piston. Reactions were observed with high-speed film and embedded pressure gages. Many of the reactions possessed characteristic secondary ignitions away from the expected combustion surface or loading surface. These ignitions frequently start when the pressure is less than 1 kBar, and they play a major role in the reaction character. After secondary ignition, reaction violence was primarily driven by the strength of the confinement in a tradeoff between pressurization due to combustion and venting after confinement has failed. The former is directly determined by the burning rate of the Comp-B and the surface area available for burning. Strand burner, closed bomb, and vented chamber experiments were conducted to examine the burning behavior and regression rate. The process seems to be reproducible up to pressures of ~100 MPa. At greater pressures, the pressurization rates indicate that Comp-B may be rapidly deconsolidating. In the vented chamber, Comp-B samples were quenched at ~35 to 125 MPa. Scanning electron microscopy of the quenched surfaces showed pits consistent with a mechanism whereby RDX particles are dislodged from the surface during the burning process. These results, when examined with results from other studies, offer an opportunity for better understanding the explosion response for Comp-B and other melt cast explosives