A simulation study of fracture toughness for a solid rocket motor contains a cracked propellant grain: Consideration of gas impingement effect

Abstract

Abstract It is essential to understand the fracture characteristics of a cracked propellant grain in a solid rocket motor during the motor ignition. In this paper, a finite element model of a solid rocket motor is developed, including the gas impingement flow field and the structural field. A circumferential crack is prefabricated on a round-hole type propellant grain. The gas pressure inside the cracked grain is obtained as a function of time by calculating the flow field. Then applying this pressure to the structural field, and J-integral at the crack tip can be calculated. The J-integral can represent the fracture toughness of the propellant. The results show that the circumferential crack in the propellant grain opens up as the gas pressure gradually increases. The J-integral values at the crack tip show an oscillating trend and are not monotonically increasing. This paper predicts the moment of crack propagation in the rocket motor grain under gas impingement conditions by comparing the JIC of the propellant.