فصلنامه مواد پر انرژی
سال هشتم شماره 4 (پیاپی 21، زمستان 1392)

In this research and according to level set method, 3D complex grains burn-back analysis is numerically simulated. The complicated grains that we have considered in this research, are included four types of difficulties that are insulated regions, different burning rates, non-uniform burning rates and oriented burning rates. To this end, the classical algorithm that is developed by authors, will be improved for simulation of above mentioned grains. In the first step, and for simulation of insulated grains, linear, quadratic, and combined insulators are considered. In the next step, the simulation of grains with different burning rates in desired directions, are added to the main program. Finally, by considering non uniform burning rate in axial and/or radial directions, improvement of the code is completed. Comparison of results in cylindrical grains according to present and analytical methods, indicate that the present algorithm is capable for simulation of complicated grains. Also, some complex grains that we can not simulate them analytically or based on the classical level set method, are considered and evaluated.

Dimethyl amino ethyl azide (DMAZ) is a good replacement for hydrazine derivatives in aerospace industries. DMAZ is in organic phase with a concentration of at least 95%. It is necessary to purify DMAZ to high concentrations. Several routs have been suggested for this purpose، in which distillation is a practical and applied method. Thermal sensitivity of DMAZ leads to conducting the process in sub-atmospheric pressures. The previous tests showed 4kPa is an optimum pressure for the process. In this paper equilibrium data for DMAZ and water at 4kPa were obtained. Results were compared with proper software to determine the best equation of state. Finally، excess molar Gibbs energy of solution was derived on the basis of equilibrium data.

An experimental study of the high velocity impact on 2/1 GLARE panels has been carried out. Four GLARE 3 panels with (Al/0/90/Al)، (Al/02/902/Al)، (Al/04/904/Al) and (Al/08/908/Al) configurations were fabricated. All panels had same aluminum thickness. Ballistic tests were conducted using flat ended steel projectiles. The failure modes and energy absorption mechanisms were characterized by observation the front and rear sides and also sectioning the panels. Some global and local failure modes due to high velocity impact were identified. The ballistic limit velocity and energy absorption capacity of each panel set was determined experimentally. Specific perforation energy was applied for comparison the ballistic efficiencies of each target. It was found that the (Al/02/902/Al) sequence has the superior specific perforation energy.