Development of mortar simulator with shell-in-shell system - problem of internal ballistics

Abstract

The shell-in-shell system used in the mortar simulator raises a number of non-standard technical and computational problems starting from the requirement to distribute the propelling blast energy between the warhead and the ballistic barrel, finishing with the requirement that the length of warhead's flight path must be scaled to combat shell firing tables. The design problem of the simulator is split into two parts -- the problem of external ballistics where the initial velocities of the warhead must be determined, and the problem of internal ballistics -- where the design of the cartridge and the ballistic barrel must be performed. Initial velocities of the warhead determined in the problem of external ballistics form the set of initial data for the problem of internal ballistics of mortar simulator with shell-in-shell system. The ballistic barrel (reusable component of the mimicking shell) must be ejected from the mortar tube and its flight path must be only few meters. Moreover, the propelling charge can be located only in the warhead and the blast energy must be distributed between the warhead and the ballistic barrel. That turns the problem of internal ballistics into a complex nonlinear dynamical problem. Its solution involves building of the numerical model, optimisation of system parameters and experimental investigations. Presented mortar simulator proved its effectiveness in combat training exercises and is fully adopted in Lithuanian Army training facilities.