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Internal ballistic equations of artillery shrapnel are established on the basis of theoretical analysis, and equivalent method used for dealing with semi-combustible cartridge case, calculation program selects the Matlab software. The simulation results are accord with the experimental data, it shows design of equations and calculation program is reasonable and credible. IntroductionsWith the requirements of development of artillery's technology, the emergence semi combustible cartridge case is a perfect combination of all advantages of combustible cartridge case and metal cartridge case. In this paper, we studied internal ballistic of lower chamber pressure artillery firing with semi-combustible cartridge case.According to the tactical technical requirements, in order to increase the damage effect of projectiles, launch projectiles need larger firing range and enough large falling angle when hit the ground target, so it must obtain different firing velocity. It is obviously that only one kind of charge cannot meet the requirements, and it must be spited into several small parts of propellant charge with different mass and shapes. But the propellant charge is incomplete combustion under low pressure when the charge is reduced to a certain amount, then the velocity distribution increased and the less quality of charge, the more obviously phenomenon. In order to address this issue the method of mixed charge is adopted that is combination of thin and thick powder charging gunpowder. In the small charging it mainly is thin charging gunpowder which can maintain constant pressure for complete combustion and fuse can remove insurance.

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Abstract. Deflection nose is a new concept of fast response control mode, partial nose of projectile can deflect certain angle relative to the axis of projectile body and pressure difference emerges in the windward and leeward side of warhead then generates aerodynamic control force, and this control way has high control efficiency and very good application prospect in the ammunition system. Nose deflection actuator based on smart material and structure makes projectile body morphing then obtains additional aerodynamic force and moment, changes the aerodynamic characteristics in the projectile flight process, produces the corresponding balance angle, sideslip angle then resulting in motor overload, adjusts flight moving posture and controls the ballistics, finally realizes shooting range changing and improves firing accuracy. In order to study characteristics of self-adaptive control projectile, numerical simulations were conducted by fluid dynamics software ANSYS FLUENT for fin stabilized rocket projectile. Computed aerodynamics on different nose delectation angle, different Mach number and different angle of attack, and compared the aerodynamic characteristics with the different nose deflection angles. Results show that the nose deflection control has bigger influence on the head of rocket projectile, and caused asymmetry of the flow field structure, make the warhead differential pressure in the windward and leeward surface increases, resulting in a larger lift. Finally, ballistics experiments were done for verification. Results can offer theoretical basis for self-adaptive rocket projectile design and optimization also provides new ideas and methods for field smart ammunition research.