| dc.description.abstract | In solid rocket motors, a strong bond at the propellant–liner interface ensures that the propellant functions as designed. If the interface degums, the propellant burn surface area will change and the performance of internal ballistics will be adversely affected. In this study, we considered two cases of motor failure to investigate methods for improving the bond strength between the propellant grain and the liner interface with the aim of achieving a tensile strength exceeding the 8 kg/cm2 requirement. We considered hydroxyl-terminated polybutadiene (HTPB) as the liner material. The HTPB-based material was conditioned and processed under the conditions of 5 to 20 torr pressure and 60°C to 70°C temperature. Further, we considered toluene diisocyanate (TDI) as the hardener and increased its contents in the liner by 0% (i.e. original content), 2%, 5%, 10%, 15% and 21.5% in order to obtain NCO/OH equivalence ratios of 1.035, 1.056, 1.087, 1.139, 1.190 and 1.258, respectively. Thereafter, bond strength tests and analyses were conducted. The tensile strength gradually increased with increasing TDI content in the liner. The bond strength was found to increase after improving the liner, performing HTPB heating and vacuum extraction pretreatments, and increasing the TDI content by 15%.
With the development of modern weapons, one of the development trends in solid propellants is to provide higher energy and burning rate. Adding a nano-metal catalyst to the propellant is an effective method for improving the burning rate and the energy of a solid propellant. A dust explosion is triggered by the rapid combustion of burnable particulate matter suspended in air. In the explosion tests, no apparent increase in pressure above that found in the blank tests was observed for Ag dust cloud with a concentration of 0.8 g/L. In addition, fine solid particles remaining after the tests showed no evidence of a combustion reaction at the end of the tests. In addition, the dust explosion behaviors of aluminum powder, RDX, and their mixtures were studied. In many manufacturing processes of propellants, high dust concentrations are unavoidable. To address the safety issues related to combustible dust, it is imperative to determine and mitigate the dust explosion risks. However, owing to the complexity of the explosion processes, dust explosion risks can be identified only by determining the explosion parameters, particularly the minimum explosible concentration of dust. It is important to analyze and identify the hazards related to manufacturing solid propellants and reduce the risk of accidents.
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