IDENTIFICATION OF EXPERIMENTAL FORM FUNCTION USING LUMPED PARAMETERS INTERIOR BALLISTICS MODELS

A method for identifying experimental form functions based on the results of interior ballistics modelling using lumped parameters models is presented. The function is defined as the relation between the ratio of the actual burning surface of a whole propellant charge, to the initial global surface of all propellant grains in the charge and the relative burnt mass of the charge. It is approximated by a function depending on several parameters. Values of the parameters are identified by fitting the results of the interior ballistics modelling to the measured maximum pressure value and the projectile muzzle velocity value. The identified experimental form functions are compared to the functions determined in closed vessel tests. The examples analyzed suggest that the use of the experimental form function enables us to take into account the process of ignition in lumped parameters models.